Oma 1

1.
Transient response in the system is basically due to
a) Forces
b) Friction
c) Stored energy
d) Coupling
Ans: (c)
2. Effect of feedback on the plant is to

a) Control system transient response
b) Reduce the sensitivity to plant parameter variations
c) Both (a) and (b)
d) None of these
Ans: (c)
3. Transfer function of a system is defined as the ratio of output to input in

a) Z-transformer
b) Fourier transform
c) Laplace transform
d) All of these
Ans: (c)
4. In an open loop system

a) Output control the input signal
b) Output has no control over input signal
c) Some other variable control the input signal
d) Neither output nor any other variable has any effect on input
Ans: (d)
5. Transfer function of a system can used to study its

a) Steady state behavior
b) Transient behavior
c) Both (a) and (b)
d) None of these
Ans: (c)
6. Electrical resistance is analogous to

a) Intertia
b) Dampers
c) Spring
d) Fluid capacity
Ans: (b)
7. Automatic control system in which output is a variable is called

a) Closed loop system
b) Servomechanism
c) Automatic regulating system
d) Process control system
Ans: (d)
8. Output of the feedback control system should be a function of

a) Input
b) Reference and output
c) Feedback signal
d) None of these
Ans: (b)
9. Steady state error is always zero in response to the displacement input for
a) Type 0 system
b) Type 1 system
c) Type 2 system
d) Type (N > 1) system for N= 0, 1, 2….N
Ans: (d)
10. Relation between Fourier integral and Laplace transformer is through

a) Time domain
b) Frequency domain
c) Both (a) and (b)
d) None of these
Ans: (c)
11. At resonance peak, ratio of output to input is

a) Zero
b) Lowest
c) Highest
d) None of these
Ans: (c)
12. 0 type system has

a) Zero steady state error
b) Small steady state error
c) High gain constant
d) Higher error with high K
Ans: (b)
13. If gain of the system is zero, then the roots

a) Coincide with the poles
b) Move away from the zeros
c) Move away from the poles
d) None of these
Ans: (a)
14. Settling time is inversely proportional to product of the damping ratio and
a) Time constant
b) Maximum overshoot
c) Peak time
d) Undamped natural frequency of the roots
Ans: (b)
15. If gain of the critically damped system is increased, the system will behave as
a) Under damped
b) Over damped
c) Critically damped
d) Oscillatory
Ans: (a)
16. If gain of the system is increased, then

a) Roots move away from the zeros
b) Roots move towards the origin of the S-plot
c) Roots move away from the poles
d) None of these
Ans: (c)
17. A low value of friction coefficient

a) Minimize the velocity lag error
b) Maximize the velocity lag error
c) Minimize the time constant of the system
d) Maximize the time constant of the system
Ans: (a)
18. Physical meaning of zero initial condition is that the

a) System is at rest and stores no energy
b) System is at rest but stores energy
c) Reference input to working system is zero
d) System is working but stores no energy
Ans: (a)
19. If overshoot is excessive, then damping ratio is

a) Equal to 0.4
b) Less than 0.4
c) More than 0.4
d) Infinity
Ans: (b)
20. For a desirable transient response of a second order system damping ratio must be
between
a) 0.4 and 0.8
b) 0.8 and 1.0
c) 1.0 and 1.2
d) 1.2 and 1.4
Ans: (a)
21. For second order linear system, setting time is
a) 1/4 of the time constant

b) 1/2 of the time constant
c) 4 times the time constant
d) 2 times the time constant
Ans: (c)
22. System generally preferred is

a) Under damped
b) Critically damped
c) Over damped
d) Oscillatory
Ans: (a)
23. For unity damping factor, the system will be

a) Under damped
b) Critically damped
c) Over damped
d) Oscillatory
Ans: (b)
24. Second-derivative input signal adjust

a) Time constant of the system
b) Time constant and supress the oscillations
c) Damping of the system
d) Gail of the system
Ans: (b)
25. In the derivative error compensation

a) Damping decreases and setting time increases
b) Damping increases and settling time increases
c) Damping decreases and setting time decrease
d) Damping increases and setting time decreases
Ans: (d)
26. If for second order system damping factor is less than one, then system response will be
a) Under damped
b) Over damped
c) Critically damped
d) None of these
Ans: (a)
27. With feedback system sensitivity to parameter

a) Decreases
b) Increases
c) Becomes zero
d) Becomes infinite
Ans: (a)
28. In a closed loop system, source power is modulated with

a) Error signal
b) Reference signal
c) Actuating signal
d) Feed back signal
Ans: (a)
29. With feedback system, transient response

a) Decays constantly
b) Decays slowly
c) Decays quickly
d) Rises fast
Ans: (c)
30. Non-Linearity in the servo system due to saturation is caused by

a) Servo motor
b) Gear trains
c) Relays
d) None of these
Ans: (a)
31. In control system non-Linearity caused by gear trains is
a) Backlash
b) Dead space
c) Coulomb friction
d) saturation
Ans: (a)
32. Time sharing of an expansive control system can be achieved by using a/an
a) a.c. control system
b) analog control system
c) Sampled date control system
d) None of these
Ans: (c)
33. Differential is used in synchro differential unit for generators only

a) Indicating difference of rotation angle of two synchro generators only
b) Indicating sum of rotation angle of two synchro generators only
c) Both (a) and (b)
d) None of these
Ans: (a)
34. Microsyn is the name given to

a) Potentiometer
b) Magnetic amplifier
c) Resolver
d) Rotary differential transformer
Ans: (c)
35. Laplace transformer is not applicable to non-linear system because

a) Non-linear systems are time-varying
b) Time domain analysis is easier than frequency domain analysis
c) Initial conditions are not zero in non-linear systems
d) Superposition law is not applicable to non-linear system
Ans: (d)
36. Value of i(0+) for the system whose transfer function is given by the equation I(s) =
(2s+3)/((s+1)(s+3)) is
a) 0
b) 2
c) 1
d) 3
Ans: (b)
37. Liner differential transformer is an

a) Electromechanical device
b) Electrical device
c) Electromagnetic device
d) Electrostatic device
Ans: (a)
38. If transfer function of the system is 1/(TS+1), then steady state error to the unity step
input is
a) 1
b) T
c) Zero
d) Infinite
Ans: (c)
39. Which of the following is not a desirable feature of a modern control system?
a) No oscillation
b) Accuracy
c) Quick response
d) Correct power level
Ans: (a)
40. Power amplification in a magnetic amplifier can be increased

a) By negative feed back
b) By positive feed back
c) With higher inductance of a.c. coil
d) None of these
Ans: (d)
41. Device used for conversion of coordinates is
a) Syschros
b) Microsyn
c) Synchro resolver
d) Synchro transformer
Ans: (c)
42. Friction coefficient is usually kept low to

a) Minimize velocity-lag error
b) Maximize velocity-lag error
c) Minimize time constant
d) Maximize speed of response
Ans: (a)
43. Most common use of the synchros is as

a) Error detector
b) Transmission of angular
c) Transmission of arithmetic data
d) For synchronization
Ans: (d)
44. To decrease time of the servomechanism

a) Decreases inertia of the system
b) Increases inertia of the system
c) Increases damping of the system
d) Decreases torque of the servomotor
Ans: (a)
45. If steady state error for type 1 system for unit ramp input is kept constant, then constant
output is
a) Distance
b) Velocity
c) Acceleration
d) Power
Ans: (b)
46. Servomechanism is called a proportional error device when output of the system is
function of
a) Error
b) Error and its first derivative
c) First derivative of error
d) None of these
Ans: (a)
47. For type 2 system, position error arises at steady state when input is
a) Ramp
b) Step displacement
c) Constant acceleration
d) None of these
Ans: (c)
48. Which of the following motor is suitable for servomechanism?

a) A.c. series motor
b) 1 ɸ induction motor
c) 2 ɸ induction motor
d) 3 ɸ induction motor
Ans: (c)
49. To decrease the number of system

a) First integrator and then differentiator is inserted
b) First differentiator and then integrator is inserted
c) Only differentiator is inserted in the forward path
d) Only integrator is inserted in the forward path
Ans: (c)
50. Servomechanism with step-displacement input is

a) Type 0 system
b) Type 1 system
c) Type 2 system
d) Type 3 system
Ans: (b)
51. If feedback is introduced in the system the transient response
a) Does not very

b) Decays very fast
c) Decays slowly
d) Dies off
Ans: (b)
52. Main difference between servomotor and standard motor is that

a) Servomotor has low inertia and higher starting torque
b) Servomotor has inertia low starting torque
c) Servomotor has high inertia and high starting torque
d) None of these
Ans: (b)
53. The frequency range over which response of the system is within acceptable units is
called the system
a) Band width
b) Modulation frequency
c) Demodulation frequency
d) Carrier frequency
Ans: (a)
54. Self balancing instrument uses

a) D.C. servomotor
b) A.C. servomotor
c) Tachometer
d) Magnetic amplifier
Ans: (b)
55. Lead compensation in the system add

a) Zeros
b) Poles
c) Both (a) and (b)
d) None of these
Ans: (b)
56. In type 1 system steady state acceleration error is

a) 0
b) 1
c) Infinity
d) None of these
Ans: (c)
57. Lead lag compensation improve

a) Transient response of the system
b) Steady state response of the system
c) Both (a) and (b)
d) None of these
Ans: (c)
58. If poles of the system are lying on the imaginary axis in s-plane, then system will be
a) Stable
b) Marginally stable
c) Conditionally stable
d) Unstable
Ans: (b)
59. If open loop transfer function of a system is G(s) H(s) = K/(S(1+T1 S)(1+T2 S)) then
system will be
a) Unstable
b) Conditionally stable
c) Stable
d) Marginally stable
Ans: (c)
60. According to Hurwitz criterion the characteristic equation s2+ 8 s3+18 s2+16 s + 5 = 0 is
a) Unstable
d) Unstable
61. A system is called absolutely stable is any oscillations set up in the system are
a) Damped out
b) Self-sustaining and tend to last indefinitely
c) Negative peaked only
d) None of these
Ans: (a)
62. To increase damping of pair of complex roots compensator used is

a) Phase lag
b) Phase lead
c) Phase lag lead
d) One with 60° lead circuit
Ans: (b)
63. Best method to determine stability and transient response of the system is
a) Bode plot
b) Signal flow graph
c) Nyquist plot
d) Root locus
Ans: (c)
64. For type 3 system, lowest frequency asymptote will have the slop of
a) 15 db/octave
b) -16 db/octave
c) 17 db/octave
d) -18 db/octave
Ans: (d)
65. If poles of system are lying on the imaginary axis in s-plane, the system will be
a) Unstable
d) Unstable
Ans: (b)
66. If a pole is added to a system it causes

a) Lag compensation
b) Lead compensation
c) Lead-lag compensation
d) None of these
Ans: (b)
67. The number of pure integrations in the system transfer function determine
a) Degree of stability
b) Stability of the system
c) Transient performance of the system
d) Steady state performance
Ans: (d)
68. For steady state transient improvement, compensator used is

a) Lead compensator
b) Lag compensator
c) Lead lag compensator
d) None of these
Ans: (c)
69. Which system conveniently see the impact of poles and zeros on phase and gain margin?
a) Root locus
b) Nyquist plot
c) Routh-Hurwitz criterion
d) Bode plot
Ans: (d)
70. Which gives the information between number of poles and zero of the closed loop
transfer function?
a) Routh Hurwitz criterion
b) Bode diagram
c) Root locus method
d) Nyquist plot
Ans: (d)
71. Factor which cannot be can cancelled from numerator and denominator of G(s) E(s)
in
a) Bode plot
b) Nyquist plot
c) Higher frequencies
d) None of these
Ans: (c)
72. To study time delay of the system which of the following is used?
a) Nyquist plot
b) Bode plot
c) Routh Hurwitz method
d) Nicholas chart
Ans: (a)
73. Intersection of root locus branches with the imaginary axis can be determined by the use
of
a) Polar plot
b) Routh’s criterion
c) Nyquist criterion
d) None of these
Ans: (b)
74. Closed loop ples are

a) Zeros of 1+G(S). H(s)
b) Zeros of G(s) H(s)
c) Poles of G(s) H(s)
d) Poles of 1 + G(s) H(s)
Ans: (a)
75. If gain is zero, then

a) Roots move away from zeros
b) Roots coincide with poles
c) Roots move away from poles
d) None of these
Ans: (b)
76. Maximum over shoot is the function of

a) Damping ratio
b) Natural frequency of oscillation
c) Both (a) and (b)
d) Damped frequency of oscillation
Ans: (b)
77. If value of gain is increased, then roots of the system will move to
a) Origin
b) Lower frequencies
c) Higher frequencies
d) None of these
Ans: (c)
78. Feed back control system are basically

a) Low pass filter
b) High pass filter
c) Band pass filter
d) Band stop filter
Ans: (a)
79. In root if 𝓴 is greater than critical value, then increasing 𝓴 will

a) Increase value of the real part of closed loop
b) Decrease value of the real part of closed loop
c) Not change value of the real part of closed loop
d) None of these
Ans: (c)
80. A liner system obeys the principle of

a) Homogeneity
b) Reciprocity
c) Superposition and homogeneity
d) None of these
Ans: (c)
81. Plot of the constant gain loci of the system is

a) Asymptote
b) Circle with centre at the origin
c) Parabola
d) Ellipse
Ans: (b)
82. If poles are more than zeros in G(S) F(S), then number of root locus segment is equal to
a) Number of poles
b) Number of zeros
c) Sum of poles and zeros
d) Difference of poles and zeros
Ans: (a)
83. In root locus technique, angle between adjacent asymptote is

a) 180°/(m + n)
b) 360°/(m + n)
c) 360°/(m - n)
d) 180°/(m - n)
Ans: (c)
84. For G(S) F(S) = (k(S+z))/(S+p), (z < p) the plot is
a) One pole on the imaginary axis

b) One zero on the right-hand side of the plane
c) One pole and one zero on the left-hand side of plane
d) 2 poles and 2 zeros on the left-hand side of plane
Ans: (c)
85. Frequency response mean

a) Transient response of a system to a sinusoidal input
b) Steady state response of a system to a sinusoidal input
c) Oscillatory response of a system to a sinusoidal input
d) None of these
Ans: (b)
86. Number of root-locus segment which do not terminate on the zeros is equal to
a) Number of poles
b) Number of zeros
c) Sum of poles and zeros
d) Difference of poles and zeros
Ans: (d)
87. Bode plot approach is applied to

a) Minimum phase network
b) Non minimum phase network
c) Any network
d) None of these
Ans: (a)
88. In a root locus plot, the increase in 𝓴 will

a) Increase damping ratio
b) Decrease damping ratio
c) Not change damping ratio
d) None of these
Ans: (b)
89. The type of transfer function used in Bode plot is

a) G(s)
b) G(j)
c) G(jw)
d) G(js)
Ans: (a)
90. In a root locus plot, increase in 𝓴 will

a) Increase overshoot of the response
b) Decrease overshoot of the response
c) Not change overshoot of the response
d) None of these
Ans: (a)
91. Bode analysis method can be applied

a) If transfer function has no poles and zeros on R.H. of s-plane
b) If transfer function has no poles on R.H. of s-plane
c) If transfer function has no zero on R.H. of s-plane
d) To all transfer functions
Ans: (a)
92. In a root locus plot, increase in 𝓴 will

a) Result in decrease in the damped and undamped natural frequencies
b) Result in increase in the damped and undamped natural frequencies
c) Not change the damped and undamped natural frequencies
d) None of these
Ans: (b)
93. Cut off is the slope of log-magnitude curve

a) At the start of curve
b) At the end of curve
c) Near the cut off frequency
d) None of these
Ans: (c)
94. Gain margin expressed in decibels is

a) Positive if Kg greater than 1 and negative for Kg less than 1
b) Negative if Kg greater than 1 and negative for Kg less than 1
c) Always zero
d) Infinity for Kg equal to 1
Ans: (a)
95. Bandwidth gives an indication of

a) Characteristic equation of the system
b) Speed of response of a control system
c) Transfer function of the control system
d) Transients in the system
Ans: (b)
96. Nyquist stability criterion requires polar plot of

a) Characteristic equation
b) Closed loop transfer function
c) Open loop transfer function
d) None of these
Ans: (c)
97. Cut off frequency is the frequency at which magnitude of closed loop frequency
response is
a) 1 db below its zero frequency

b) 2 db below its zero frequency
c) 3 db below its zero frequency
d) 4 db below its zero frequency
Ans: (c)
98. In Nyquist criterion roots of the characteristic equation are given by

a) Zeros of open loop transfer function
b) Zeros of closed loop transfer function
c) Poles of closed loop transfer function
d) Poles of open loop transfer function
Ans: (c)
99. For all frequencies, a unit circle in the Nyquist plot transformer into
a) Db line of amplitude plot in Bode diagram
b) 1 db line of amplitude plot in Bode diagram
c) Either (a) and (b)
d) None of these
Ans: (c)
100. Transfer founction, when the bode diagram is plotted should be of the form
a) (1+T)
b) (1+S)
c) (Ts)
d) (1+Ts)
Ans: (d)
101. For relative stability of the system which of the following is sufficient?
a) Gain margin
b) Phase margin
c) Both (a) and (b)
d) None of these
Ans: (c)
102. Slope in Bode plot is expressed as

a) – 6 db/decade
b) – 6 db/octave
c) – 7 db/octave
d) – 8 db/octave
Ans: (b)
103. Polar plots for+ve and –ve frequencies
a) Are always symmetrical
b) Can never be symmetrical
c) May be symmetrical
d) None of these
Ans: (a)
104. Gain margin of a first or second order system is

a) Zero
b) 100
c) 1
d) Infinity
Ans: (d)
105. Frequency range over which response of the system is within acceptable limits is called
system
a) Modulation frequency
b) Demodulation frequency
c) Carrier frequency
d) Band width
Ans: (d)
106. By adding a pole at s = 0, Nyquist plot of the system will

a) Shift 90° clockwise
b) Shift 90° anticlockwise
c) Shift 180°
d) Not change at all
Ans: (a)
107. A complex-conjugate pair of poles near the jw axis will produce a

a) High oscillatory mode of transient response
b) Steady state mode of response
c) Sinusoidal mode of response
d) None of these
Ans: (a)
22. The string efficiency of the insulator can be increased by

a) Increasing the number of strings in the insulator
b) Increasing ratio, capacity to earth/capacity per insulator
c) Correct grading of the various capacitances
d) Reducing the number of strings
Ans: C
23. The dielectric strength of the air barometric pressure of 76 cm and 25°C is
a) 30 KV per meter
b) 21.1 KV r.m.s. per cm
c) 21.1 KV r.m.s. per cm
d) 21.1 KV per cm
Ans: B
24. In case of parallel wires the visual corona begins

a) At disruptive critical voltage
b) At visual critical voltage which is higher than disruptive critical voltage
c) At lower voltage than disruptive critical voltage
d) None of the above
Ans: B
25. corona helps in avoiding the effect of lightning or surges on the transmission line.
a) true
b) false
Ans: A
26. Corona will not involve energy loss when the transmission is d.c.
a) true
b) false
Ans: B
27. High tension cables can be used upto

a) 22 kV
b) 11 kV
c) 44 kV
d) 33 kV
Ans: D
28. Sheath is used in the cables to
a) Prevent the moisture from entering the cable
b) Provide the strength to the cable
c) Avoid the chances of the rust on the stands
d) Provide proper insulation
Ans: A
29. The extra high-tension cables are usually filled with thin oil under pressure of gas filled
because
a) The pressure of oil or gas will avoid the formation of the voids
b) The pressure will provide the strength to the cable
c) The pressure will enable the cable to withstand the high voltage
d) The gas and oil at high pressure will work as insulator
Ans: A
30. The voltage stress in maximum in the cable

a) At the surface of the sheath
b) At the surface of the conductor
c) At the surface of the insulator
d) At the surface of the armouring
Ans: B
31. The intersheaths in the cables are used

a) To provide the uniform stress distribution
b) To avoid the requirement of the good insulation
c) To minimize the stress
d) To avoid moisture
Ans: A
32. The graded cables used the dielectric of different
a) permittivities
b) permeabilities
c) (a) and (b) both
d) (a) or (b)
Ans: (a)
33. The charging current in the cables

a) Lags the voltage by 90°
b) Leads the voltage by 90°
c) Leads the voltage by 180°
d) Lags the voltage by 45°
Ans: (b)
34. The dielectric losses increase with the increase of temperature

a) true
b) false
Ans: (a)
35. If A, B, C and D are the constants of the medium transmission line, which of the
following relation is correct ?
a) AB – CD = - 1
b) AD + BD = 1
c) BC – AD = - 1
d) AC – BD = 1
Ans: (c)
36. What is the unit of constant D?

a) ohm
b) mho
c) henry
d) none of the above
Ans: (d)
37. While finding out the relation between VS and VR capacitance is neglected in
a) A short transmission line
b) A long transmission line
c) A medium transmission line
d) All the above cases
Ans: (a)
38. The capacitance in the medium transmission line is

a) Lumped
b) Distributed over the entire length of line
c) (a) or (b) depending on the transmission voltage
d) Variable non-linearity over line
Ans: (b)
39. The surge impedance of the underground cable is more than the surge impedance of the
overhead transmission line.
a) true
b) false
Ans: (b)
40. The surge impedance for an underground cable is

a) 60 to 100 ohms
b) 40 to 60 ohms
c) 40 to 600 ohms
d) 30 to 75 ohms
Ans: (b)
41. The surge impedance of the long transmission line is given by

a) Zc = √(L/C)
b) Zc =√(Z/Y)
c) Zc =√(Y/Z)
d) Zc =√(R/Y)
Ans: (b)
42. The surge impedance cannot be determined in the terms of A, B, C and D constants of the
line.
a) true
b) false
Ans: (b)
43. Ferranti effect states that under certain conditions the sending end voltage is
a) Less that receiving end voltage

b) Greater than receiving end voltage
c) Equal to receiving end voltage
d) Abnormally high
Ans: (a)
44. The surge impedance of a line having negligible resistance and no shunt leakage, is pure
resistance, i.e., Zc = √(L/C).
a) true
b) false
Ans: (a)
45. The use of the transformers does not affect the performance of the transmission line.
a) true
b) false
Ans: (b)
46. The entire line performance can be determined by

a) Sending end power circle diagram
b) Receiving end power circle diagram
c) Universal power circle diagram
d) (a) or (c)
Ans: (c)
47. Transducer type regulators are electromechanical voltage regulators.

a) true
b) false
Ans: (b)
48. If the shunt admittance of the transmission line is neglected, the maximum power will
occur when torque angle
a) 45°
b) – 90°
c) 90°
d) 180°
Ans: (c)
49. If the receiving end voltage is assumed same as the sending end voltage, and the
impedance of the line is the resistance of the line. What will be the maximum steady state
power transmitted over the line.
a) (VR2)/Z
b) (VS2)/Z
c) zero
d) very high
Ans: (c)
50. If the reactance of the line is varied and resistance is kept constant, the maximum steady
state power that could be transmitted over the line would be greater when
a) X = R/√3
b) X = 3R
c) X = √3R
d) X = R/3
Ans: (c)
51. The equal area criterion of stability is applicable to

a) Two machine system and infinite busbars
b) One machine system and infinite busbars
c) Multi-machine system only
Ans: (b)
52. if the torque angle δ increases infinitely, the system will show
a) stability
b) instability
c) steady state stability
Ans: (b)
53. If VS = VR = 33 kV for three phase transmission and reactance is 13 ohms per phase. What
will be the maximum power transmission per phase?
a) 29 MW
b) 28 MW
c) 30 MW
d) 60 MW
Ans: (b)
54. The switching operations will not affect the transient stability of the system.
a) true
b) false
Ans: (b)
55. The size of the feeder is determined primarily by
a) The current it is required to carry
b) The percentage variation of voltage in the feeder
c) The voltage across the feeder
d) The distance over which the transmission is made
Ans: (a)
56. If the voltage is increased n times, the current in the feeder is reduced to (for a given
power delivered )
a) 1/n times of the original
b) 1/n2 times of the original
c) 1/√n times of the original
d) √n times of the original
Ans: (a)
57. In the d.c. three wire transmission system the cross-section of the neutral is generally
a) 1/4 of the outer conductors
b) 1/2 of the outer conductors
c) 1/3 of the outer conductors
d) Equal to the outer conductors
Ans: (b)
58. The radial system of the distribution is better than the ring main system
a) true
b) false
Ans: (b)
59. The metal clad is related to

a) Amplidyne
b) Switchgear system
c) Synchros
d) Relays
Ans: (b)
60. As the transmission voltage increases the percentage resistance drop

a) Increases
b) Decreases
c) Will not change
d) Will increase in random manner
Ans: (b)
61. As the transmission voltage increases the volume of the conductor
a) Increases
b) Decreases
c) Will not change
d) Will increase proportionately
Ans: (b)
62. The power transmission capacity of the transmission line is

a) Proportional to the square of the operating voltage
b) Inversely proportional to the voltage
c) Proportional to the voltage
d) Inversely proportional to the square of the voltage
Ans: (a)
63. The overall capital cost of the transmission decreases the voltage of transmission
increases.
a) true
b) false
Ans: (a)
64. Which of the following power plant has the maximum efficiency?
a) Thermal power plant
b) Hydro-electric power plant
c) Atomic Reactor
d) MHD
Ans: (c)
65. The corona loss in the transmission line can be reduced by increasing spacing between the
conductors or the diameter of the conductors.
a) true
b) false
Ans: (a)
66. The bundle conductors are preferred for EHV transmission line because
a) It is easy to fabricate thin conductors and combine them to make a bundle
b) Overall inductance of the line is reduced and corona loss and radio influences are
minimum
c) Height of the tower is reduced and hence cheap transmission
d) Fabrication of the conductor is cheap
e) Of erection difficulties
Ans: (b)
67. EHV d.c. transmission over large distance is cheaper than EHV a.c. transmission
a) true
b) false
Ans: (a)
68. The percentage reactance is defined as

a) The percentage of the ratio of change in reactance in transient condition to the total
reactance of the machine
b) The percentage of the ratio of change in reactance in transient condition of the total
resistance of the machine
c) The percentage of the ratio of voltage drop due to reactance synchronous machine to
the rated voltage when full load rating current is flowing
d) Either (a) and (c)
Ans: (c)
69. If the secondary of the transformer having the reactance of 4% is short circuited with
normal voltage applied to the primary the symmetrical short circuit current will be
a) 4 times of the full load current
b) 25 times of the full load current
c) 2 times of the full load current
d) 8 times of the full load current
e) 40 times of the full load current
Ans: (b)
70. If the base kVA is 25,000 then a 5000 kVA alternator with 8% reactance will have
a) A 4% reactance
b) A 40% reactance
c) A 16% reactance
d) A 20% reactance
Ans: (b)
71. The percentage reactance can be converted into ohmic value which the following
formula
a) Xohms = (X(%) ×100 (kV)2)/kVA

b) Xohms = (X(%) ×1000 (kV)2)/kVA
c) Xohms = (X(%)×(KV)2)/(1000 kVA)
d) Xohms = (X(%)×10(kV)2)/kVA
Ans: (d)
72. When an alternator is short circuited on the three phases, it settles down to the steady
short circuit value and limited by
a) Sub-transient reactance
b) Transient reactance
c) Synchronous reactance
d) Either (a) or (c)
Ans: (c)
73. The short circuit current of an alternator when short circuited on three phases will be
a) Zero as time goes to infinity
b) Maximum when time goes to infinity
c) Infinity when time goes to infinity
d) Small as time goes to infinity but not zero
e) None of the above
Ans: (a)
74. The reactors used to limit the short circuit current in the alternators have very small
resistance in comparison to reactance
a) Because the high resistance will not help to limit the short circuit current
b) To avoid the energy waste
c) Because the high resistance will raise the temperature and insulation of reactor will be
spoiled
d) To improve power factor
Ans: (b)
75. ‘a’ is an operator used to symmetrical component analysis

a) Which rotates the vector, it operates upon, through an angle 90° in the clockwise
direction
b) Which rotates the vector, it operates upon, through an angle 120°, in the counter-
clockwise direction
c) Which rotates the vector, it operates upon, through an angle120°, in the clockwise
direction
d) Which rotates the vector, it operates upon, through an angle 240°, in the clockwise
direction
Ans: (b)
76. Which of the following statement is true?

a) a = 0.5 – j 0.866
b) a = 0.5 + j 0.866
c) a4 = - a
d) a2 = - (1 + a)
Ans: (d)
77. The arc voltage produced in the circuit breaker is always

a) In the phase with the are current
b) Lagging the arc current by 90°
c) Leading the arc current by 90°
d) Leading the are current by 180°
Ans: (a)
78. The fusing factor of the fuse always greater than one.
a) true
b) false
Ans: (a)
79. The material used for fuse must have

a) Low melting point and low specific resistance
b) Low melting point and high specific resistance
c) High melting point and low specific resistance
d) Low melting point with any specific resistance
Ans: (b)
80. The Buchholz relay is used to protect the

a) Alternators against all internal faults
b) Oil immersed transformers against all internal faults
c) Synchronous motors against all internal faults
d) Transmission lines against all short circuit faults
Ans: (b)
81. The torque produced in induction type relay (shaded pole structure) is
a) Proportional to square of current

b) Proportional to the current
c) Inversely proportional to the square of the current
d) Inversely proportional to the current
Ans: (c)
82. In an impedance relay the torque produced by the current element is balanced against the
torque of a voltage element
a) true
b) false
Ans: (a)
83. If the fault occurs near the impedance relay, the V/I ratio will be
a) Lower than that of if fault occurs away from the relay
b) Higher than that of if the fault occurs away from the relay
c) Constant for all distances
Ans: (a)
84. Admittance relay is

a) The directional relay
b) The none directional relay
c) The impedance relay
Ans: (a)
85. The impedance relay can be used for earth faults and phase faults too
a) true
b) false
Ans: (a)
86. A saturable reactor can be used to realize the relay action.

a) true
b) false
Ans: (a)
87. A 132 kV three phase, 50 Hz overhead line is 50 km long and has a capacitance to earth
for each line of 0.0157 microfarad/km. What will be the inductance of the arc suppression
coil suitable for the system.
a) 4 henrys
b) 4.3 henrys
c) 5 henrys
d) 2 henrys
Ans: (b)
88. The earthing transformer is used

a) To avoid the harmonics in the transformers
b) To provide artificial neutral earthing where the neutral points of the three phase
system are not accessible
c) To improve the current capacity of the neutral wire
Ans: (b)
89. The third harmonics current flows from the generator line terminals through the system
and returns by way of comparatively low zero-sequence reactance path to the neutral
terminals will give rise to
a) Overheating of generator only
b) Overheating of generator and neutral resistors of earthing transformer
c) Overheating of earthing transformer only
Ans: (b)
90. The save value current (r.m.s.) which a human body can tolerate for greater than 3
seconds
a) 15 mA
b) 25 mA
c) 5 mA
d) 9 mA
Ans: (d)
91. The effect of shock in the human body will depend on
a) Line voltage
b) Line current
c) Current flowing in the body
Ans: (c)
92. To protect the power transformer (Y-Y, with neutral earthed) against fault, the current
transformer will have
a) Delta-delta connection
b) Delta-star connection
c) Star-delta connection
d) Star-star connection
Ans: (a)
93. To protect the power transformer (Delta-delta) against fault current transformer will have
b) Delta-star connection
c) Star-delta connection
d) Star-star connection
Ans: (d)
94. Which of the following alloy is used for the core of the transformer?
a) Invar
b) Nichrome
c) Elinvar
d) Perminvar
Ans: (d)
95. The requirement of the insulation in the transformer or electrical machines design is
determined by
a) Current
b) Voltage
c) Rate of the change of the current
d) Rate of the change of voltage
e) Power
Ans: (b)
96. The class C insulation can withstand

a) 180° C
b) 150° C
c) 200° C
d) 105° C
Ans: (a)
97. If the star connected circuit is transformed into delta connected circuit, which of the
following statement is true?
a) Ra = R1R2+ R2R3+ R1R3 /R3
b) Ra = R3/R1+ R2
c) Ra = R3/R1 R2 + R2R3+ R1R3
d) Ra = R1 + R2 + R3 /R1 + R2
Ans: (a)
98. The location of the lightning arresters is

a) Near the transformer
b) Away from the transformer
c) Near the circuit breaker
d) Away from the circuit breaker
Ans: (a)
99. The steady-state stability of the power system can be increased by

a) Using machines of high impedance
b) Connecting lines in series
c) Connecting lines in parallel
d) Reducing the excitation of the machines
Ans: (c)
100. With the single frequency transients, the ratio of peak restriking voltage/time between
voltage zero and peak voltage is known as
a) Recovery voltage
b) Restriking voltage
c) Rate of rise restriking voltage
d) Active recovery voltage
Ans: (c)
101. Which of the following power system distribution gives the greater reliability?
a) Radial system of the distribution

b) Ring system of the distribution
c) D.C. three wire system of the distribution
d) A.C. three phase four wire system
Ans: (b)
102. The diversity factor is defined as the

a) (Average demand)/(Maximum demand)
b) (Sum of consumers maximum demand)/(Maximum load on the station)
c) (Maximum demand)/(Sum of consumers maximum demand)
d) (Average demand)/(Maximum load on the station)
Ans: (b)
103. In the transformers

a) High tension winding is used near the core
b) High tension winding is used away from the core
c) Low tension winding is used near the core
d) Low tension winding is used away from the core
Ans: (a)
104. For the system shown below the base, voltage is

a) 11 kV for whole system
b) 132 kV for the whole system
c) 11 kV for generator side and 132 kV for transmission side
d) Cannot be determined from the given data
Ans: (c)
105. The efficiency of the transformer line between
a) 70 to 80%
b) 80 to 90%
c) 90 to 98%
Ans: (c)
106. For the three phase transformer, which of the following statement is true?
a) True ratio = line voltage ratio
b) True ratio = phase voltage ratio
c) True ratio = √3 phase voltage ratio
d) True ratio = √3 lines voltage ratio
Ans: (a)
107. A distribution transformer usually is a

a) Star-delta transformer
b) Delta-star transformer
c) Star-star transformer
d) Delta-delta transformer
Ans: (b)
108. From a resistance test carried on transformer, it was found that the resistance of primary
and secondary windings are 8 ohms and 16 ohms respectively. The primary will be
a) H.V. side
b) L.V. side
c) Cannot be determined from the test
d) Either of two may be L.V. side
Ans: (b)
109. The effect of series capacity on a transmission line is to improve

a) The steady stability
b) The transient stability
c) (a) and (b) both
Ans: (a)
110. The power intended to be available even under emergency condition is called
a) Firm power
b) Hot reserve
c) Cold reserve
d) Spinning reserve
Ans: (c)
111. Which of the following generating station has the minimum running cost?
a) Hydro-electric station
b) Nuclear power station
c) Thermal power station
d) Diesel power plant
Ans: (a)
112. Which of the following motors is used for locomotive drive?

a) D.C. shunt motor
b) D.C. series motor
c) A.C. series motor
d) Synchronous motors
Ans: (b)
113. The rating of the circuit breaker used for a system whose has been increased from
10,000 to 20,000 kVA will
a) Increase
b) Decrease
c) Remain constant
d) Remain same but size of the circuit breaker increases
Ans: (a)
114. The inductive interference between power and communication line can be minimized by
a) Increasing the distance between the conductors
b) Transposition of the power line
c) Transposition of the communication line
d) (b) and (c) both
Ans: (d)
115. The two transmission lines of the surge impedance of 600 ohms each is linked by a
cable. What should be the surge impedance of the cable is there were no reflection at the
junction?
a) 300 ohms
b) 30 ohms
c) 600 ohms
d) 60 ohms
Ans: (c)
116. A delta and star capacitances configurations are shown. Find CY in term of CD, so that
the capacitances between any corresponding points in the star circuit
a) CY = 2CL
b) CY = 3CD
c) CY = CD
d) CY = CD/2
Ans: (b)
117. For 11 kV underground system, it is possible to work upon a length of

a) 800 miles
b) 100 miles
c) 400 miles
Ans: (b)
118. The magnetizing inrush current which energisation of a transformer will be

a) Larger than full load current
b) Less than full load current
c) Equal to full load current
d) Approximately equal to load current
Ans: (a)
119. Overfluxing protection is recommended for

a) Generator transformer of the power plant
b) Auto-transformer of the power plant
c) Station transformer of the power plant
d) Distribution transformer
Ans: (a)
120. Harmonic restraint in differential protection for transformer is provided to prevent the
mal-operation caused by
a) Magnetizing inrush current
b) Unmatched VTs
c) Unmatched CTs
d) Demagnetizing flux
Ans: (a
121. Which of the following statement is true if restricted earth fault protection is
provided to star winding of the generator transformer
a) One CT in each phase and fourth in the neutral are provided and their secondaries
are connected in parallel
b) One CT is provided in the neutral
c) Two CT are provided, one in R-phase and other in Y-phase with a CT in neutral
d) In fact CTs are not required at all the fault current is not very high
Ans: (a)
122. Series capacitors are used to

a) Improve line voltage
b) Compensate for line inductive reactance
c) Compensate for line capacitive reactance
Ans: (b)
123. Air blast circuit breakers for 400 kV power system are design to operate in
a) 5 sec
b) 0.5 sec
c) 0.1 sec
d) 50 millisecond
e) 100 micro-second
Ans: (d)
124. Carrier transfer-trip schemes do not operate faster than carrier blocking schemes
a) True
b) False
Ans: (b)
125. The auxiliary power supply system in any kind of power station is arranged such that the
power supplies are
a) Redundant only
b) Redundant and independent only
c) Reliable
d) Independent
Ans: (b)
126. High water level of a boiler drum can damage

a) Boiler tubes only
b) Turbine and steam line
c) Turbine only
Ans: (c)
127. Which of the following statement is true ?

a) The zero sequence reactance of a transformer is approximately equal to negative
sequence reactance.
b) The zero sequence reactance of transformer is approximately equal to positive
sequence reactance.
c) The zero sequence reactance depends on the connection and winding of the
transformer.
d) The zero sequence reactance is large than negative sequence reactance but less
than positive sequence reactance in the transformer.
Ans: (c)
128. The capacity voltage transformer is used

a) Upto 11 kV
b) Upto 33 kV
c) Above 220 kV
d) Above 132 kV
e) Above 110 kV
Ans: (d)
129. The MHO relay inherently a

a) Directional unit
b) None-directional unit
c) None of the above
Ans: (a)
130. The operation time of instantaneous relay is usually

a) Of an order of a few second
b) Without any time delay
c) One second
d) 0.01 second
Ans: (d)
131. For which of the following ratings of the transformer differential protection is
recommended
a) Above 50 kV
b) Equal to and above 5 MVA
c) Equal to and above 20 MVA
d) Either of the above cases
Ans: (b)
132. When the stator neutral of a generator is grounded through a resistor, the stator ground
fault is detected through
a) An under-voltage relay connected across the resistor
b) An over-voltage relay connected across the resistor
c) An over-current relay connected to the current CT
d) Any ground fault relay
Ans: (c)
133. The longitudinal differential relaying system responds in faults between turns of
winding of a transformer.
a) True
b) False
Ans: (a)
134. Over voltage protection is recommended for

a) Steam turbine generators
b) Hydro-electric generators
c) Gas turbine generators
d) All the above
Ans: (d)
135. Distance relays are generally

a) MHO relays
b) Reactance relays
c) Impedance relays
d) Split-phase relays
Ans: (a)
136. Which of the following relay is preferred for phase fault on short transmission line
a) Reactance relay
b) Impedance relay
c) MHO relay
d) Induction type relay
Ans: (a)
137. In case of multi-terminal line the first zero of the distance relay is set to reach 80 to
90%of the distance from the nearest terminal.
a) True
b) False
Ans: (a)
138. The knee-point in the magnetizing characteristics of a CT is a point where 10% increase
in the secondary voltage increases
a) The exciting current by 10%
b) The exciting current by 30%
c) The exciting current by 50%
d) The exciting current by 14.4%
e) The primary voltage by 10%
Ans: (c)
139. Fuses are used where relays and circuit breakers

a) Fail to interrupt heavy short circuit currents
b) Are not economically justified
c) Are not available
d) Require more care and maintenance
e) Take more time to clear the fault
Ans: (b)
140. The impedance relay does not have directional features.

a) True
b) False
Ans: (a)
141. The short circuit in any windings of the transformer is the result of
a) Impulse voltage
b) Insulation failure
c) Mechanical vibration
d) Magnetostriction force
e) Loose connection
Ans: (b)
142. Percentage differential protection in a transformer is recommended to prevent mal-

operation due to
a) External fault currents
b) Internal fault currents
c) Magnetizing currents
Ans: (c)
143. harmonic restraint in differential relay is provided so that the relay operates when
harmonic current in transformer
a) Does not exceed 15% of fundamental
b) Exceed 15% of fundamental
c) Exceed 14.4% of fundamental
d) Exceed 17.3% of fundamental
Ans: (b)
144. The inverse definite mean time relays are used for over-current and earth fault protection
of transformer against
a) External short circuits
b) Internal short circuits
c) Heavy overloads
d) All the above cases
Ans: (b)

a) Shunt reactors are used for power factors improvement
b) Shunt reactor are used to control the line voltage
c) Shunt reactors are used to reduce the line impedance
d) Shunt reactors are used to eliminate line to ground capacitance
Ans: (a)
146. When a stator neutral of a generator is earthed through a distribution transformer, the
stator earth fault is detected through
a) An over-voltage relay connected across the secondary of the transformer
b) An over-current relay connected across the secondary of the transformer
c) An under-voltage relay connected across the secondary of the transformer
Ans: (a)
147. Split-phase relaying responds to faults between turns of a transformer.

a) True
b) False
Ans: (a)
148. A single ground fault in the field circuit of a large generator causes damage to the rotor.
a) True
b) False
Ans: (b)
149. Which of the following relays are used for phase fault on long line?
a) Impedance relays
b) Reactance relays
c) MHO relays
Ans: (a)
150. For a detection of the occurrence of the severe synchronizing power surges
a) Impedance relays are best suited
b) MHO relays best suited
c) Reactance relays are best suited
d) Split-phase relays are best suited
Ans: (b
151. The protection from negative sequence currents is provided for
a) Transformers
b) Generators
c) Transmission line
d) Motors
Ans: (b)
152. phase comparison relays require voltage transformers.

a) True
b) False
Ans: (b)
153. If high pressure heaters of steam cycle in power plant have high water level, what
precaution shall be taken?
a) Trip the turbine
b) Trip the boiler
c) Trip the boiler feed pump
d) Bypass the heater from waterside and close extraction valve
Ans: (d)
154. Which of the following device shall be used to measure the stator winding temperature
of the generator
a) Thermometer
b) Resistance thermometer
c) Pyrometer
d) Thermocouple
Ans: (b)
155. How many relays will be used to detect inter-phases fault of a three line?
a) One
b) Two
c) Three
d) Six
Ans: (b)
156. What will be the value of current I shown in the following circuit?
a) Zero
b) 10 A
c) 100 A d) 1 A
Ans: (e)
157. If the transmission voltage is increased from 11 kV to 33 kV, then diameter of the
conductor will be
a) Increased
b) Decreased
c) Same as for 11 kV system
Ans: (b)
158. Which of the relation is correct if the transmission voltage of a power line is V and
regulation is R?
a) RV = K
b) R/V = K
c) R = KV2
d) R = KV3
e) R = K/V2
where K is constant.
Ans: (e)
159. The characteristic impedance of the power line is the same as surge impedance
a) True
b) False
Ans: (b)
160. The power line resistance are concerned to

a) Surge impedance
b) Characteristic impedance
c) (a) and (b) both
Ans: (a)
161. If the height of the transmission tower is decreased, the inductance of the line will
a) Increase
b) Decrease
c) Remain same
d) Increase exponentially
Ans: (c)
162. If the height of the transmission tower is decreased, the capacitance of the line will
a) Increase
b) Decrease
c) Remain same
d) Decrease exponentially
Ans: (a)
163. AC system has the following disadvantages over DC system

a) Skin effect exists
b) Line regulation is more
c) Charging current exists
Ans: ()
164. The power loss is important for the design of

a) Generator
b) Motor
c) Feeder
d) Transmission line
Ans: (d)
165. The voltage regulation is an important factor for the design of

a) Generator
b) Motor
c) Feeder
d) Transmission line
Ans: (c)
166. The booster transformer is used to increase the voltage at

a) Intermediate points
b) Receiving end of transmission line
c) Sending end of transmission line
d) Any point desired
Ans: (a)
167. Which of the statement is true?

a) The fault current in an impedance relay will be maximum when fault occurs near the
relay.
b) The fault current an impedance relay will be minimum when fault occurs near the
relay.
c) The fault current in an impedance relay will be maximum when fault occurs away from
the relay.
d) The fault current in an impedance relay will be maximum when fault occurs near the
transmitting end.
Ans: (a)
168. The lightning arrester acts as

a) Surge diverter
b) Surge coil
c) Surge absorber
d) Surge reflector
Ans: (a)
169. The air blast circuit-breakers are preferred for intermittent duty.
a) True
b) False
Ans: (b)
170. The under-voltage relay can be used for

a) Busbars
b) Motor
c) Transformers
d) Generator
e) All of them
Ans: (e)
171. The capital cost of the thermal power plant will depend on
a) The size of the plant

b) The fuel cost
c) (a) and (b) both
Ans: (a)
172. The fixed tariff consists of the interest on the capital cost, depreciation, insurance and
other taxes.
a) True
b) False
Ans: (a)
173. The running cost of the plant comprises cost of fuel, consumable materials and operation
and maintenance cost.
a) True
b) False
Ans: (a)
174. Which of the following plant has highest capital cost?

a) Diesel power plant
b) Thermal power plant
c) Hydro-power plant
d) Nuclear power plant
Ans: (d)
175. The running cost, among conventional power plant, is minimum for hydro-plant.
a) True
b) False
Ans: (a)
176. The hydro-power plant operates at higher load factor than thermal power plant.
a) True
b) False
Ans: (a)
177. Which of the following frequency range is suitable for A.C. network analyser?
a) 400 Hz to 500 Hz
b) 50 Hz to 100 Hz
c) 40 Hz to 50 Hz
d) dc to 50 Hz
Ans: (a)
178. The distance relay basically measures

a) current
b) voltage
c) impedance
d) either of the above
Ans: (c)
179. The relay with inverse time characteristic will operate within
a) 2 secs
b) 5 to 10 secs
c) 5 to 20 secs
d) 20 to 30 secs
Ans: (b)
180. The disruptive critical voltage will

a) Increase if the moisture content in the air increases
b) Decreases if the moisture content in the air decreases
c) Decrease if the moisture content in the air increases
d) Decrease if the moisture content in the air increases
Ans: (c)
181. corona loss in the power lines is more in winter season than the summer season.
a) True
b) False
Ans: (a)
182. The single phasing relays are used for the protection of
a) Single phase motor only
b) Two-phase motors only
c) Two single phase motor running in parallel
d) Three phase motors
Ans: (d)
183. Two protection zone in the electrical transmission system is decided

a) Location of PT
b) Location of CT
c) Relay’s size
d) Relay’s sensitivity
Ans: (b)
184. Which of the following device will receive Voltage Surge first traveling on the
transmission line
a) Step-down transformer
b) Relays
c) Switchgear
d) Lightning arresters
Ans: (d)
185. The fault impedance of the line is

a) Less than the impedance of healthy line
b) More than the impedance of healthy line
c) Equal to the impedance of the healthy line
Ans: (a)
186. Which of the following parameter can be neglected for a short line?
a) Resistance
b) Inductance
c) Reactance
d) Capacitance
Ans: (d)
187. The stability of a salient pole alternators is better than the stability of a non- salient pole
alternators.
a) True
b) False
Ans: (a)
188. Series reactors should have

a) High resistance
b) Low resistance
c) High impedance
d) Low impedance
Ans: (b)
189. Which of the following frequency variation for power frequency is as per IS?
a) 2.5%
b) 5%
c) ±5%
d) ±2.5%
Ans: (c)
190. Which of the following device will be preferred to control the power system voltage?
a) Transformers
b) Shunt capacitors
c) Series capacitors
d) Electronic amplifiers
e) Synchronous conductors
Ans: (e)
191. The back-up protection is provided with time delay during which main protection to
the power system must operate when fault occurs. If main protection fails to operate, the
back-up protection will operate.
a) True
b) False
Ans: (a)
192. What kind of insulator will be used if the direction of the transmission line is changed?
a) Suspension type of insulators
b) Pin type of insulators
c) Rubber insulators
d) Strain type insulators
Ans: (d)
193. Which of the insulator disc will be exposed to maximum electrical stress?
a) One which is near to the conductor
b) One which is away from the conductor
c) One which is at the bottom of string
d) One which is in the center of string
Ans: (a)
194. If ACSR conductor has specification as 48/7, which of the following explanation is
correct for the conductor?
a) The conductor has 48 strands of steel and 7 strands of aluminum.
b) The conductor has 7 strands of steel and 48 strands of aluminum.
c) The conductor has 48 strands.
d) The conductor has 55 strands.
Ans: (b)
195. The skin effect in the conductor increases the effective value of resistance of the
conductor.
a) True
b) False
Ans: (a)
196. The inductance in the transmission line is caused by the

a) Current flowing in the conductor
b) Current flowing in the other conductor
c) Voltage difference among the conductors
Ans: (b)
197. Which of the parameters can be neglected which calculation the transmission line faults?
a) Reactance
b) Resistance
c) Capacitance
d) Inductance
Ans: (c)
198. Which of the following systems are more prone to faults?

a) Motors
b) Generators
c) Underground cables
d) Overhead lines
e) Transformers
f) Reactors
Ans: (d)
199. The power loss due to corona effect depends on

a) The surface condition of the conductor
b) The material density of the conductor
c) (a) and (b)
Ans: (c)
200. The dielectric losses of an electrical system are 50 Watts. What will be the dielectric
losses if the voltage of the system is doubled?
a) 50 watts
b) 100 watts
c) 300 watts
d) 200 watts
Ans: (d)
201. The capacitance of the transmission line will be affected if the distance between
conductors and earth is varied.
a) True
b) False
Ans: (a)
202. The inductance of the transmission line will be affected if the distance between
conductors and earth is varied.
a) True
b) false
Ans: (b)
203. The sending end voltage of the transmission line controls the
a) active power
b) reactive power
c) (a) and (b) both
Ans: (b)
204. The frequency of the power system control the

a) Active power
b) Reactive power
c) (a) and (b) both
d) None of them
Ans: (a)
205. Which of the following equipment one will choose to study the stability of A.C. power
system?
a) Energy meter
b) Network analyser
c) Network synthesizer
d) (b) or (c)
Ans: (b)
206. The breaking torque which plugging the machine at zero speed will be
a) Zero
b) High
c) Small
Ans: (b)
207. The dynamic breaking of the machine offers the highest breaking torque in comparison
to other breaking methods.
a) True
b) False
Ans: (b)
208. The drop in the terminal voltage of the shunt generator on load may be attributed to
a) Increase in armature resistance
b) Drop in field current due to armature reaction
c) Drop in field current due to drop in armature resistance
d) (b) and (c) both
Ans: (d)
209. If the load is not connected to the d.c. series motor then
a) It will not build up the voltage
b) It will build up very high voltage
c) It will have very low speed (d) none of the above
Ans: (a)
211. The power factor of an alternator depends on load.
a) True
b) False
Ans: (a)
212. Which of the following transmission line has refection coefficient as one?
a) Open circuit transmission line
b) Short circuit transmission line
c) Either (a) or (b)
d) Long transmission line
Ans: (a)
213. Which of the following transmission line has the reflection coefficient of minus one?
a) Open circuit transmission line
b) Short circuit transmission line
c) Long transmission line
d) Short transmission line
Ans: (b)
214. Which of the following circuit breaker has high reliability and minimum maintenance?
a) Oil circuit breaker
b) Air blast circuit breakers
c) Vacuum circuit breakers
d) Circuit breaker with SF6 gas
Ans: (d)
215. The insulation resistance of HV circuit breakers should be of the order of

a) 50 ohms to 100 ohms
b) 100 K ohms to 1000 K ohms
c) 10 Mega ohms
d) 50 Mega ohms to 100 Mega ohms
e) 100 Mega ohms and above.
Ans: (e)
216. If the capacitance of the transmission line is increased, the transmitted power will
a) Remain same
b) Increase
c) Decrease
d) Tend to zero at receiving end
Ans: (b)
217. If the inductance of transmission line is decreased, the power transmitted will
a) Increase
b) Decrease
c) Will not change
d) Tend to be very high at receiving end
Ans: (a)
218. The installation of a synchronous motor at receiving end of the transmission line will
a) Only improve the p.f. of the line under large loads
b) Keep same voltage at sending and receiving ends
c) Help in transmitting larger power
d) Decrease the inductance of the line
e) (a), (b) and (c) only
Ans: (e)
219. The difference between sending end voltage and receiving end voltage of transmission
line controls
a) Active power
b) Reactive power
c) Frequency
d) None of these
Ans: (b)
220. What will be the reflection coefficient of the wave of load connected to transmission line
if surge impedance of the line is equal to load?
a) Unity
b) Infinity
c) Zero
d) 10
Ans: (c)
221. What will be the reflection coefficient in above question of surge impedance is half
of the load?
a) 2/3
b) 1/3
c) 3
d) 1/6
Ans: (b)
222. Which of the following statements is correct?

a) Arc in a circuit breaker is interrupted at maximum current
b) Arc in a circuit breaker is interrupted at zero current
c) Arc in a circuit breaker is interrupted at maximum voltage
d) Arc in a circuit breaker is interrupted at minimum voltage
Ans: (b)
223. The sag of a transmission line with 50 M span is 1 M. What will be the sag if the height
of the transmission line is increased by 20%?
a) 1.2 M
b) 2 M
c) 1.25 M
d) 1 M
Ans: (d)
224. For which of the following increased value of horizontal tension three will be increase of
20% in tension of the line for certain span?
a) 50%
b) 10%
c) 5%
d) 20%
Ans: (d)
225. The method of image cannot be used to find out the

a) Line capacitance
b) Line inductance
c) Line resistance
d) (b) and (c)
Ans: (d)
226. Which of the following insulator will be selected for high voltage application?
a) Strain type
b) Disc type
c) Suspension type
d) Pin type
Ans: (c)
227. The strain type is insulators used when

a) The transmission line is dead ended
b) The direction of transmission line changes
c) The transmission line short
d) (a) and (b)
Ans: (d)
228. The voltage regulation is the main criterion for designing the
a) Transmission line
b) Feeder
c) Motor
d) Generator
Ans: (d)
229. The power loss is very important factor for designing the
a) Feeder
b) Transmission line
c) Motor
d) Generator
Ans: (b)
230. Which of the following method may be used to inject reactive power in the transmission
line?
a) Series capacitor
b) Series capacitors
c) Synchronous capacitors
d) All above
Ans: (d)
101. The efficiency of the transformer is independent of power factor.
a) true
b) false
Ans: (b)
102. The condition for the maximum efficiency of the transformer is that
a) Copper losses are half of the iron losses
b) Copper losses are equal to iron losses
c) Copper losses are negligible in comparison to iron losses
d) Iron losses are zero
Ans: (b)
103. If the iron loss and full load copper losses are given then the load at which two losses
would be equal ( i.e. corresponding to maximum efficiency ) is given by
a) full load × (iron loss)/(f.l.cu-loss)
b) full load × ((iron loss)2)/(f.l.cu-loss)
c)full load × √((iron loss)/(f.l.cu-loss))
d) full load × √((f.l.cu-loss)/(iron loss))
Ans: (c)
104. The distribution transformers are designed to keep core losses minimum and copper
losses are relatively less important because
a) The primary of such transformers is energized for all twenty-four hours and core
losses occur throughout the day whereas copper losses will occur only when secondary
is supplying load
b) Core losses are always more than copper losses
c) Core losses may destroy the insulation
d) Core losses will heat up the oil of the transformer rapidly
Ans: (a)
105. The tapping in the transformer are always provided in the low voltage side
a) true
b)false
Ans: (b)
106.Enumerate the conditions for successful parallel operation of the single phase
transformers
a) The percentage impedance should be equal
b) The transformers should be properly connected with regard in polarity
c) The primary winding of the transformers should be suitable for the supply system
voltage and frequency
d) The voltage ratings of transformers of primary and secondary winding should be
identical
Ans: ()
107. What will happen if the transformers working in parallel are not connected with regard
to polarity?
a) Incorrect polarity will result in dead short-circuit
b) The transformers will not share load in proportion to their KVA rating
c) The power factors of two transformers will be different from the power factor of
common load
Ans: (a)
108. What will happen if the percentage impedances of the two transformers working in
parallel are different?
a) Parallel operation will not be possible
b) Parallel operation will still be possible, but the power factors at which the two
transformers operate will be different from the power factor of the common load
c) Transformers will be over heated
d) Power factors of both of the transformers will be same
Ans: (b)
109. Which of the following connections is most suitable and economical for small, high-
voltage transformers?
b) Star-star connection
c)Star-delta connection
d)Delta-star connection
Ans: (b)
110. Delta-delta connection is economical for large, low-voltage transformers in which

insulation problems is not urgent.
a) true
b) false
Ans: (a)
111. The average power factor at which open-delta bank of single phase transformers
operates is less than that of load.
a) true
b) false
Ans: (a)
112. Scott connection is used
a) To accomplish three phase to three phase transformation only
b) To accomplish three phase to two phase transformation only
c) To accomplish three phase to three phase and three phase to two phase
transformation
Ans: (c)
113. Under balanced load conditions, main transformer rating in the Scott connection is
a) 10% greater than teaser transformer
b) 15% greater than teaser transformer
c) 57.7% greater than teaser transformer
d) 66.6% greater than teaser transformer
Ans: (b)
114. If the load is balanced on one side of the transformer in the Scott connection, the load is
balanced on the other side as well.
a) true
b) false
Ans: (a)
115. If K is the transformation ratio of main transformer in the Scott connection then the
transformation ratio of the teaser will be
a) K/√3
b) √(3/2K)
c) 2K/√3
d) √(K/2)
Ans: (c)
116. The rotor slots are usually given slight skew in the squirrel case indication motor
a) To increase the tensile strength of the rotor bars and hence strength
b) To reduce the magnetic hum and locking tendency of the rotor
c) To see the copper used
d) Because of easy in fabrication
Ans: (b)
117. The starting torque of the slip ring induction motor can be increased by
a) Adding external resistance to the rotor
b) Adding the external inductance to the rotor
c) Adding both resistance and inductance to the rotor
d) Adding external capacitance to the rotor
Ans: (a)
118. What will happen if the relation speed between the rotating flux of stator and rotor of the
induction motor is zero?
a) The rotor will not run
b) The rotor will run at very high speed
c) The slip of the motor will be zero
d) The torque produced will be very large
Ans: (a)
119. When the rotor starts rotation the frequency of the rotor of induction motor will depend
on relative speed of the stator and the rotor.
a) true
b) false
Ans: (a)
120. A 400 KW, 3 phase, 440 volts, 50 Hz AC induction motor has a speed of 950 rpm on
full load. The machine has 6 poles. The slip of machine will be
a) 0.06
b)0.10
c) 0.04
d) 0.05
Ans: (d)
121. If the rotor of the induction motor is assumed non-inductive, the torque acting on each
conductor will be positive or unidirectional.
a) true
b) false
Ans: (a)
122. Which of the following statement is most appropriate if T is the starting torque
developed in the rotor and V is the supply voltage to the stator.
a) T is proportional to V2
b) T is proportional to V
c) T is proportional to √V
d) T is proportional to V1/4
Ans: (a)
123. A change of 5% in supply voltage to an induction motor will produce a change of

approximately
a) 5% in the rotor torque
b) 7% in the rotor torque
c) 25% in the rotor
d) 10% in the rotor torque
Ans: (c)
124. The torque of a rotor in an induction motor under running condition is maximum
a) At the value of the slip which makes rotor reactance per phase equal to the resistance
per phase
b) At the value of the slip which makes the rotor reactance half of the rotor resistance
c) At the unit value of the slip
d) At the zero value of the slip
Ans: (a)
125. By varying the rotor resistance in the slip ring induction motor the maximum torque can
be achieved at any desired slip or speed of.
a) true
b) false
Ans: (a)
126. The maximum torque of an induction motor varies directly as applied voltage.
a) true
b) false
Ans: (a)
127. The shape of the torque/slip curve of induction motor is

a) hyperbola
b)parabola
c) straight line
d) rectangular parabola
Ans: (d)
128. Which of the following statement is correct when referred to induction motor?
a) The maximum torque will depend on rotor resistance
b) Although the maximum torque does not depend on rotor resistance yet the exact
location of maximum torque is depend on it
c) The maximum torque will depend on standstill reactance of rotor
d) The slip of the induction motor decreases as the torque increases
Ans: (b)
129. If an induction motor has a slip of 2% at normal voltage, what will be the approximate
slip when developing the same torque at 10% above normal voltage?
a) 1.6%
b) 2%
c) 1.65%
d) 1.1%
Ans: (c)
130. The slip of the induction motor can be measured by comparing the rotor and stator
supply frequencies.
a) true
b) false
Ans: (a)
131. When the frequency of the rotor of induction motor is small, it can be measured by
a) Galvanometer
b) D.c. moving coil millivoltmeter
c) D.c. moving coil ammeter
d) A.c. voltmeter
Ans: (b)
132. The rotor efficiency of induction motor is called

a) I.H.P.
b) F.H.P.
c) B.H.P.
Ans: (c)
133. The rotor efficiency of induction motor is defined as the ratio of actual speed of rotor to
synchronous speed of rotor.
a) true
c) false
Ans: (a)
134. The synchronous watt can be defined as follows :

a) This is the unit of rating of synchronous machine
b) This is the unit of torque defined at radius unit
c) This is the torque, which at the synchronous speed of the machine under
consideration, would develop a power of 1 watt
d) This is the unit of the power when the power factor in the power equation omitted
Ans: (c)
135. The synchronous wattage of an induction motor equals the power transferred across the
air gap to the rotor in the induction motor.
a) true
c) false
Ans: (a)
136. When it is said that an induction motor is developing a torque of 900 synchronous watts,
it means that the rotor input is 900 watts and that torque is such that the power developed
would be 900 watts provided the rotor was running synchronously and developing the same
torque.
a) true
c) false
Ans: (a)
137. The power output of induction motor will be maximum when

a) The equivalent load resistance is equal to the standstill reactance of the motor
b) The equivalent load resistance is equal to the resistance of the rotor
c) The equivalent resistance is equal to the standstill leakage impedance of the motor
d) The slip is zero
Ans: (c)
138. The complete circle diagram of induction motor can be drawn with the help of data
found from
a) no load test
b) blocked rotor test
c) (a) and (b) both
d) (a), (b) and stator resistance test
Ans: (d)
139. The transformation ratio of the induction motor cannot be defined in terms of stator and
rotor currents.
a) true
b) false
Ans: (b)
140. The maximum torque of induction motor varies directly as standstill reactance of rotor.
a) true
b) false
Ans: (b)
141. The value of transformation ratio of an induction motor can be found by

a) Short circuit test only
b) Open circuit test only
c) Slip test
d) Stator resistance test
Ans: (a)
142. The power scale of circle diagram of an induction motor can be found from
a) No load test only
b) Short circuit test only
c) Stator resistance test
Ans: (b)
143. The starting torque of induction motor cannot be determined from circle diagram
a) true
b) false
Ans: (a)
144. It is advisable to avoid line-starting of induction motor and use starter because
a) Starting torque is very high
b) Motor takes five to seven times its full load current
c) It will pick-up very high speed and may go out of step
d) It will run in reverse direction
Ans: (b)
145. The induced e.m.f. in the rotor of an induction motor is proportional to

a) Supply voltage only
b) Relative velocity between flux and rotor conductors
c) (a) and (b) both
d) Slip
Ans: (c)
146. The relation between maximum torque and full load torque (T max, Tf respectively)
when referred to induction motor is given by
a) Tf/Tmax =2a/(a2 + s2)
b) Tf/Tmax =2/(a2 + s2)
c) Tf/Tmax =2as/(a2 + s2)
d) Tf/Tmax =a/(a2 + s2)
Ans: (c)
Where s is the slip and a = R2/X2 = (Resistance of the rotor)/(Resistance of the rotor)
147.In the above question the relation between standstill torque (Ts) and maximum torque
(Tmax) is given by
a) Ts/Tmax = 2a/(1 + a2 )
b) Ts/Tmax = 2a/(S2 + a2 )
c) Ts/Tmax = 2/(1 + s2 )
d) Ts/Tmax = 2a/(S2 + 1)
Ans: (a)
148. The slip of the induction motor can be calculated if the rotor copper losses and rotor
input are known.
a) True
b) False
Ans: (a)
149. The auto-starters (using three auto-transformers) can be used to start cage induction
motor of the following type :
a) Star connected only
b) Delta connected only
c) (a) and (b) both
Ans: (c)
150 The torque developed in the cage induction motor with auto-starter is
a) K × torque with direct switching
b) K/ torque with direct switching
c) K2 × torque with direct switching
d) K2/torque with direct switching
Ans: (c)
Where tapping of transformation ratio K is used in case of auto-transformer.
151. Percentage tapping required of an auto-transformer for a cage motor to start the motor
against 1/4 of full load will be
a) 70%
b) 71%
c) 71.5%
d) 72.2%
Ans: (d)
When the short circuit current on normal voltage is 4 times the full load and full load slip
is 30%.
152. The start-delta switch is equivalent to auto-transformer of ratio (when applied to delta
connected cage induction motor)
a) 57%
b) 56.5%
c) 86.6%
d) 58% approximately
Ans: (d)
153. The rotor current can be reduced by introducing star connected resistance starter in the
rotor circuit of the cage motor and slip ring motor as well.
a) True
b) False
Ans: (b)
154. The slip ring motor can be started under load conditions.
a) True
b) False
Ans: (a)
155. The crawling in the induction motor is caused by

a) Improper design of the machine
b) Low voltage supply
c) High Loads
d) Harmonics developed in the motor
Ans: (d)
156. Cogging in the induction motor usually occurs at high voltage.

a) True
b) False
Ans: (b)
157. The outer cage in the double squirrel cage motor has low resistance copper bars.
a) True
b) False
Ans: (b)
158. The torque/speed characteristics of double squirrel cage induction motor may be taken to
be sum of two motors, one having a high resistance rotor and other a low resistance one.
a) True
b) False
Ans: (a)
159. When the equivalent circuit diagram of double squirrel cage induction motor is
constructed the two rotor cages can be considered
a) In parallel
b) In series parallel
c) In series
d) In parallel with stator
Ans: (a)
160. The speed of the cage induction motor cannot be controlled from the rotor side.
a) True
b) False
Ans: (b)
161. Which of the following methods is easily applicable to control the speed of the
squirrel cage induction motor?
a) Rotor rheostat control

b) By operating two motors in cascade
c) By injecting an e.m.f. in the rotor circuit
d) By changing the number of stator poles
Ans: (d)
162. Rotor rheostat control to control the speed of the induction motor is only applicable to
slip-ring induction motors.
a) True
b) False
Ans: (a)
163. The injected e.m.f. in the rotor of induction motor must have
a) The same frequency as the slip frequency
b) The same phase as the rotor e.m.f.
c) High value for the satisfactory speed control
d) Zero frequency
Ans: (a)
164. The additional stator winding is used in the compensated repulsion motor
a) To improve power factor and provide better speed regulation
b) To eliminate armature reaction
c) To prevent hunting in the motor
d) To provide mechanical balance
Ans: (a)
165. Repulsion start induction-run motor can be applicable to commercial refrigerators.

a) True
b) False
Ans: (a)
166. The rotation of the repulsion induction motor can be reversed by the usual brush shifting
arrangement.
a) True
b) False
Ans: (a)
167. The power factor improvement of a.c. series motor is only possible by
a) Increasing the magnitude of inductances of field and armature winding
b) Decreasing the magnitude of reactances and armature winding
c) Equalizing the armature resistance to armature reactance
Ans: (b)
168. If the number of the turns on the field winding in a.c. series motor is decreased, the
speed of motor increases but torque decreases.The same torque can be achieved by
a) Increasing the number of turns on armature winding proportionately
b) Decreasing the number of turns on armature winding
c) Increasing armature resistance
d) Equalizing the armature resistance to the armature reactance
Ans: (a)
169. In conductively-compensated a.c. series motors, the compensating winding is

a) Connected in parallel with the armature
b) Short-circuited and has no interconnection with the motor circuit
c) Connected in series with the armature
Ans: (c)
170. The current in inductively compensated winding of the a.c. series motor is proportional
to the armature current and 180 degree out of phase.
a) True
b) False
Ans: (a)
171. The huge voltage, induced in the short-circuited coil (by transformer action) of a.c.
series motor when commutation takes place is neutralized by
a) Increasing inductance of the compensating winding
b) Increasing resistance of the compensating winding
c) Decreasing the number of turns in the compensating winding
d) Shunting the winding of each commutating pole with non-inductive resistance
Ans: (d)
172. A universal motor is defined as a motor which may be operated either on d.c. or single
phase a.c. supply at
a) Same output but different speeds
b) Same speed and different output
c) Approximately same output and same speed
d) Synchronous speed
Ans: (c)
173. It is preferred to use single turn coil in the armature of the single phase a.c. series motors
a) To facilitate commutation and avoid sparking at the brushes
b) To reduce the resistance of the armature
c) To reduce the resistance of the armature
d) To reduce the weight of the armature
Ans: (a)
174. Which of the following motor is unexcited single phase synchronous motors?
a) A.C. series motor
b) Universal motor
c) Repulsion motor
d) Reluctance motor
Ans: (d)
175. Which of the following motors is most suitable for signalling devices and many kinds of
timers?
a) D.C. series motor
b) A.C. series motor
c) Induction motor
d) Reluctance motor
Ans: (d)
176. The wide-open type slots in the design of stator of alternator will present the
following disadvantage?
a) The size of the machine will increase

b) The size of the stator will increase
c) Air gap flux is distributed in the tufts and produce ripples in the wave of generated
e.m.f.
Ans: (c)
177. What kind of rotor is most suitable for turbo-alternators which are designed to run at
high speed?
a) Salient pole type
b) None-salient pole type
c) (a) or (b)
Ans: (b)
178. The power developed in the alternator having salient type rotor is less than of having
non-salient pole.
a) True
b) False
Ans: (b)
179. The damping winding in the synchronous motors is often used

a) To prevent hunting only
b) To prevent hunting and provide the starting torque
c) To maintain proper synchronism
d) To provide the starting torque only
Ans: (b)
180. The turbo-alternators are seldom characterized by small diameters and very long axial or
rotor length.
a) True
b) False
Ans: (b)
181. The maximum speed of an alternator at power frequency of 50 Hz will be

a) 3600 rpm
b) 3300 rpm
c) 3000 rpm
d) 1500 rpm
Ans: (c)
182. Which of following statement is correct?

a) Short pitched coils in the alternators are used to reduce the size of the machines.
b) Short pitched coils are used to reduce the harmonics or to eliminate the harmonics
from the generated e.m.f.
c) Short pitched coils are used to provide accurate phase difference of 120 degree to
one phase to other.
d) Short pitched coils are used to reduce copper losses.
Ans: (b)
183. The disadvantage of using short pitched coils in the alternator is that
a) Total induced e.m.f. is increased
b) Total induced voltage is reduced
c) Total induced voltage is distorted
d) Total induced voltage is more and hence more insulation is required
Ans: (b)
184. The coil span factor is defined as

a) (vector sum of induced e.m.fs. per coil)/(terminal voltage of the generator)
b) (arithmetic sum of induced e.m.fs. per coil)/(vector sum of induced e.m.fs. per coil)
c) (vector sum of induced e.m.fs. per coil)/(arithmetic sum of induced e.m.fs. per coil)
d) (arithmetic sum of induced e.m.fs. per coil)/(terminal voltage of the generator)
Ans: (c)
185. The induced e.m.f. in an alternator with distributed winding is always more than of with
concentrating winding.
a) True
b) False
Ans: (b)
186. A three phase, 4 pole, 24- slots alternator has its armature coil short pitched by one slot.
The distribution factor of alternator will be
a) 0.96
b) 0.9
c) 0.933
d) 0.966
Ans: (d)
187. In case of an alternator, the power factor of the load has a considerable effect on the
armature reaction unlike d.c. generators.
a) True
b) False
Ans: (a)
188. When the power factor of load is unity, the armature flux of an alternator will be
a) Demagnetizing
b) Cross-magnetizing
c) Square waveform
d) N phase with current
Ans: (b)
189. When the load has power factor zero lagging, the main flux of the alternator will
decrease.
a) True
b) False
Ans: (a)
190. The armature reaction of an alternator will be completely magnetizing when

a) Load power factor is unity
b) Load power factor is zero lagging
c) Load power factor is zero leading
d) Load power factor is 7.0 lagging
Ans: (c)
191. The synchronous reactance is defined as the
a) Reactance due to armature reaction of the machine

b) Reactance of synchronous machine
c) Reactance due to leakage flux
d) Combined reactance due to leakage of flux and armature reaction
Ans: (d)
192. In case of leading load power factor, the terminal voltage of alternator as the fall on
removing the full load.
a) True
b) False
Ans: (a)
193. The rise of the voltage of alternator when the load is thrown off is same as the fall in the
voltage when full load is applied.
a) True
b) False
Ans: (b)
194. Give the three methods of determining the voltage regulation of the alternator.
i) Synchronous Impedance Method
ii) M.M.F. Method
iii) Potier Triangle Method
Ans: ()
195. The synchronous impedance method will not give accurate voltage regulation because
a) The value of synchronous impedance found is always less than actual value
b) The value of synchronous impedance found is always less than the actual value
c) The value of the synchronous impedance is independent of saturation
d) The reactance due to armature reaction is considered separately
Ans: (b)
196. The value of the voltage regulation found by the M.M.F. method is always less than the
actual value.
a) True
b) False
Ans: (a)
197. Which of the following methods is better to find the voltage regulation?
a) M.M.F. Method
b) Potier Triangle Method
c) Synchronous Impedance Method
Ans: (b)
198. The operation of connecting an alternator in parallel with another alternator or with
common bus bar is known as
a) Proper machine
b) Mechanizing
c) Synchronizing
d) Asynchronizing
Ans: (c)
199. Give the three conditions for the proper synchronization of alternator
i) The terminal voltage for the incoming alternator must be same as bus bar voltage.
ii) The speed of the incoming machine must be such that its frequency (=pn/120) equals
bus bar frequency.
iii) The phase of the alternator voltage must be identical with the phase of the bus bar
voltage. It means that switch must be closed at (or very near) the instant of the two
voltage have correct relationship.
Ans: ()
200. In three phase alternators, it is necessary to synchronize one phase only, the other phases
will be synchronized automatically.
a) True
b) False
Ans: (a)
201. When the alternators are running in proper synchronism the synchronizing power will be
zero
a) True
b) False
Ans: (a)
202. If the two alternators are running in proper synchronism and the voltage of one machine
is suddenly increased
a) The machine will burn
b) Both of the machines will stop
c) The synchronization torque will be produced to restore further synchronism
d) Synchronization cannot be attained automatically
Ans: (c)
203. If the input prime-move of an alternator is kept constant but the excitation is changed
then
a) The reactive component of the output is changed
b) The active component of the output is changed
c) The power factor of the load remains constant
d) (a) and (b) takes place simultaneously
Ans: (a)
204. The load taken up by the alternator directly depends upon the driving torque or in other
words upon the angular advance of its rotor.
a) True
b) False
Ans: (a)
205. A synchronous motor is inherently self-starting motor.

a) True
b) False
Ans: (b)
206. The working of synchronous motor is, in many ways, similar to

a) The power transformer
b) The hydraulic motor
c) The gear train arrangement
d) The transmission of mechanical power by a shaft
Ans: (d)
207. The coupling angle or load angle of synchronous motor is defined as

a) The angle between the rotor and the stator poles of same polarity
b) The angle between the rotor and the stator poles of opposite polarity
c) The angle between the rotor and the stator teeth
Ans: (b)
208. The coupling angle of synchronous motor is independent of load.

a) True
b) False
Ans: (b)
209. The torque developed by the synchronous motor is independent of coupling angle.
a) True
b) False
Ans: (b)
210. The back e.m.f. set up in the stator of synchronous motor will depend on
a) The rotor excitation only
b) The rotor excitation and speed both
c) The rotor speed only
d) The coupling angle only
Ans: (a)
211. If the synchronous motor (properly synchronized to the supply) is running on no load
and is having negligible loss then.
a) The stator current will be very high
b) The stator current will be zero
c) The stator current will be very small
d) The back e.m.f. will be more than the supply voltage
Ans: (b)
212. The maximum power developed in the synchronous motor will depend on
a) The supply voltage only
b) The rotor excitation only
c)The rotor excitation and supply voltage both
d) The rotor excitation, supply voltage and maximum value of coupling angle (90 degree)
Ans: (d)
213. The armature current of the synchronous motor

a) Has large values for low excitation only
b) Has large values for high excitation only
c) Has large values for low and high excitation
d) Has large current for low lagging excitation
Ans: (c)
214. The minimum armature current of the synchronous-motor

a) Corresponds to 0.8 power factor
b) Corresponds to zero power factor
c) Corresponds to 0.866 power factor
d) Corresponds to unity power factor
Ans: (d)
215. The synchronous motor can be used as phase advancer.

a) True
b) False
Ans: (a)
216. A synchronous capacitor is nothing but a synchronous motor running on no load with
over excitation.
a) True
b) False
Ans: (a)
217. If the field of the synchronous motor is left short circuited and connected to supply
through auto-transformer
a) The motor will run at its normal speed
b) The motor will just crawl
c) The motor will run as induction motor
d) The armature will burn because there is no back e.m.f. in the armature
Ans: (c)
218. The synchronous motor can be operated at desired power factor by varying the
excitation to the motor.
a) True
b) False
Ans: (a)
219. The rotary convertor can be used to

a) Convert a.c. to d.c.
b) Convert d.c. to a.c.
c) Convert liner motion to rotary motion
d) (a) and (b) both
Ans: (d)
220. A rotary convertor is used to convert a.c. to d.c. but cannot be used to convert d.c. to a.c.
a) True
b) false
Ans: (a)
221. A 2 kW single phase rotary convertor operates at full load from 230 voltage a.c.
source. Assuming unity power factor and 100% efficiency the d.c. current will be
a) 6 A
b) 6.15 A
c) 8.7 A
d) 5 A
Ans: (b)
222. A rotary convertor can be run as a

a) Induction motor
b) Synchronous motor
c) D.c. series motor
d) D.c. compound motor
Ans: (a)
223. In the operation of the poly-phase rotary convertors, which of the following should be
introduced between the a.c. sources and slip rings?
a) Amplifier
b) Rectifier
c) Transformer
d) Diode
Ans: (a)
224. Which of the following statements is true?

a) A rotary convertor can be called a Synchronous invertor.
b) A rotary convertor can be called a Synchronous convertor.
c) A rotary convertor can be called a Synchronous divertor.
d) A rotary convertor can be called a Synchronous capacitor.
Ans: (b)
225. Which of the following rotary convertors is used in the standard practice?
a) Single phase rotary convertor.
b) Three phase rotary convertor.
c) Six phase rotary convertor.
d) Twelve phase rotary convertor.
Ans: (c)
226. For a given temperature rise and hence output, a six-phase convertor is smaller than
three or two phase convertor.
a) True
b) False
Ans: (a)
227. Given the four methods to control d.c. voltage of rotary convertor :
a) By using tap changing transformer.
b) Series reactance control method.
c) Induction regular.
d) Synchronous booster control method.
Ans: ()
228. The mercury arc rectifier is used as

a) Convertor only
b) Inventor only
c) (a) and (b) both
d) Transducer
Ans: (c)
229. The arc between the anode and cathode of mercury arc rectifier will persist
a) When anode is as positive potential with respect to cathode
b) When anode is at negative potential with respect to cathode
c) When anode will repel the electrons
d) When anode is at very low temperature
Ans: (a)
230. The purpose of introducing reactor in the ignition circuit of mercury arc rectifier is
a) To limit the rate of change of flux in the circuit
b) To limit the voltage of the circuit
c) To limit the rate of change of the current in the circuit
d) To limit the current in the circuit
Ans: (d)
231. The advantage of using larger phase mercury arc rectifier is that
a) They are easily available
b) They work noiselessly
c) They are very cheap
d) Their output is much smoother
Ans: (d)
232. The utility factor of mercury-arc rectifier is defined as

a) (actual power)/(full load rating)
b) (wattless power component)/(full load rating)
c) (actual power)/(half load rating)
d) (total a.c. input)/(total d.c. output)
e) (total d.c output)/(total d.c. input)
Ans: (a)
233. Angle of overlap is related to

a) Diode rectifier
b) Silicon controlled rectifier
c) Mercury-arc rectifier
d) Metal rectifier
Ans: (c)
234. Give the three types of voltage drop when mercury-arc rectifier is on load :
a) Reactance drop
b) Mean resistance drop
c) Arc voltage drop
Ans: ()
235. The utilization factor of the six-phase mercury arc rectifier is more than that of three-
phase mercury-arc rectifier.
a) True
b) False
Ans: (b)
236. The utilization factor is maximum for
a) Three-phase mercury arc rectifier

b) Six-phase mercury arc rectifier
c) twelve-phase mercury arc rectifier
d) Single phase mercury arc rectifier
Ans: (a)
237. If the air gap of the induction motor is increased

a) The power factor will increase
b) The power factor will decrease
c) The magnetizing current of the rotor will increase
d) The magnetizing current of the rotor will decrease
e) The speed of the motor will decrease
Ans: (d)
238. The squirrel cage induction motor has
a) One slip rings
b) two slip rings
c) three slip rings
d) zero slip rings
Ans: (d)
239. What will happen if the supply terminals of d.c. shunt motor are interchanged
a) motor will stop
b) motor will run at its normal speed in the same direction as it was running
c) the direction of rotation will reverse
d) motor speed will increase
Ans: (c)
240. An amplidyne can be used as

a) a d.c. series motor
b) a d.c. shunt motor
c) a d.c. compound motor
d) magnetic amplifier
Ans: (c)
241. The torque/slip characteristic of induction motor is shown, which is the unstable region?
a) A
b) B
c) C
d) D
Ans: (b)
242. Find the odd man out

a) Tachometer
b) Voltmeter
c) Ammeter
d) Galvanometer
Ans: (a)
243. The mechanical load across the induction motor is equivalent to electrical load of
a) R2 (1/s – 1)
b) R2 (1/s – 1)
c) R2 (s – 1)
d) 1/R2 (s – 1)
Ans: (b)
Where R2 is the resistance of the rotor in terms of secondary and s is the slip of motor.
244. If the supply frequency to the transformer is increased the iron loss
a) Will decrease
b) Will increase
c) Will not change
d) Will reach nearly zero
Ans: (b)
245. In the d.c. motors iron losses occur in

a) The yoke
b) The pole shoe
c) The armature
d) The field
Ans: (b)
246. With the use high flux density in the transformer

a) The size of core will decrease
b) Less copper will be used
c) Core losses will decrease
d) Voltage output will decrease
Ans: (a)
247. The induced e.m.f. in the armature of d.c. machine rotating in the stationary field will be
a) Sinusoidal voltage
b) Direct voltage
c) Sinusoidal with even harmonics
d) Sinusoidal with oil harmonics
Ans: (a)
248. The air gap between poles has

a) No magnetic field
b) No magnetic unless the poles are far apart
c) A strong magnetic field
d) A magnetic field if the poles tough
Ans: (c)
249. Magnetic induction results in

a) Induced poles opposite from the original poles
b) Induced poles the same as the original field
c) Two north poles
d) An induced magnetic field but no induced pole
Ans: (a)

a) Iron, steel, and nickel are magnetic materials.
b) Copper, iron, steel, and air are magnetic materials.
c) Paper, wood, and steel are magnetic materials.
d) Iron is magnetic materials but steel is non-magnetic.
Ans: (a)
251. In an electromagnet
a) Current must flow through the coil to produce magnetic field

b) The magnetic field has the same strength with or without current
c) Current must flow but no voltage need be applied across the coil
d) The coil must have high resistance for minimum coil current
Ans: (a)
252. The motor action in a wire conducting current can be produced

a) Without any additional magnetic field
b) By moving the conductor from a weaker field towards stronger field
c) By moving the conductor from stronger field towards weaker field
d) By producing the motion by not rotation
Ans: (c)
253. The requirement for producing induced voltage is

a) Magnetic flux moving across a conductor
b) Magnetic flux moving across a dielectric
c) An insulated wire free from any external magnetic field
d) A bare wire moving parallel to an external magnetic field
Ans: (a)
254. A 5:1 voltage step up transformer has 120 volts across the primary and 600 ohms
resistance across the secondary. Assuming 100% efficiency the primary current equals
a) 1/5 amp
b) 500 ma
c) 10 amps
d) 20 amps
e) 5 amps
Ans: (e)
255. In a transformer, the voltage induced in the secondary winding must always be 90
degree out of phase with the
a) Primary voltage
b) Primary current
c) Secondary voltage
d) Secondary current
Ans: (b)
256. A ferrite core has less eddy-current loss than an iron a core because
a) Ferrites have low resistance
b) Ferrites have high resistance
c) Ferrites have low permeability
d) Ferrites have high hysteresis
Ans: (b)
257. Which of the following motors is usually used in household refrigerators?

a) D.c. shunt motor
b) Reluctance motor
c) Single phase induction motor (split phase start or induction run motor)
d) Synchronous motor
Ans: (c)
258. If the refrigerator unit runs continuously maintaining cabinet coil, the failure of unit is
attributed to
a) Extreme hot weather conditions
b) Poor door seal at gasket
c) Defective motor
d) Defective thermostat
Ans: (d)
259. The maximum temperature permitted for Class A insulation is

a) 180° C
b) 105° C
c) 120° C
d) 155° C
Ans: (b)
260. The cotton, silk paper, and wood are

a) Class A insulation
b) Class Y insulation
c) Class H insulation
d) Class B insulation
Ans: (b)
261. Rheostatic breaking gives greater braking torque than plugging.

a) True
b) False
Ans: (b)
262. Which of the following rules states that the direction of an induced current is always
such that the magnetic field which it produces reacts in opposition to the change of flux.
a) Thumb rule
b) Lenz’s law
c) Kirchhoff’s law
d) Faraday’s law
Ans: (b)
263. What conditions are necessary for an induced voltage to be created by means of rotation.
a) A magnetic field
b) Movably placed loops conductors (turns)
c) Lump conductors
d) (a) and (b) both
Ans: (d)
264. In the following diagram of a line conductor, in which direction do the magnetic lines of
force run if the observer is looking in the direction of current?
a) Counter-clockwise around the conductor
b) Clockwise around the conductor
c) Around the conductor
d) Outside the conductor
Ans: (b)
265. Which of the following rule is applied to above question to field direction of magnetic
lines?
a) Left-hand rule
b) Right-hand rule
c) Corkscrew rule
d) Lenz’s law
Ans: (c)
266. In the adjacent figure, what kind of voltage is generated by linear movement of a
horizontally or vertically loop in or counter to the direction of magnetic field?
a) A D.C. voltage
b) An A.C. voltage
c) No voltage
d) Pulse voltage
Ans: (c)
267. What kind of voltage is induced in a loop conductor rotating in an homogeneous

magnetic field?
a) A.C.
b) D.C.
c) No voltage
d) Pulse voltage
Ans: (b)
268. If a loop conductor is rotated in the magnetic field, a voltage is induced in it. This
voltage increases only with the
a) Density of the magnetic lines of force
b) Active length of conductor in exciting field
c) Velocity of the loop
d) Length of conductor, velocity and flux density
Ans: (d)
269. A loop conductor is rotated in a homogeneous magnetic field the magnetic flux
a) Changes its intensity constantly
b) Changes its direction with constant density
c) Changes in intensity with its direction periodically
d) Changes its intensity with its direction randomly
Ans: (c)
270. The operation of the electric generator and motor is based on the interaction between
a) Magnetic field and electric field
b) Magnetic field and electric current
c) Electric field and law of induction
d) Law of induction and dynamo-electric principle
Ans: (b)
271. What type of current is normally used to excite the synchronous and DC generators?
a) DC
b) AC single phase
c) AC three phase
d) AC two phase
Ans: (a)
272. Under what conditions will an Electromotive force be exerted on an electric conductor
in a magnetic field?
a) The conductor must have diameter
b) The conductor must have current passing through it
c) Magnetic field must be intensified
d) The conductor must be in coil from
Ans: (b)
273. Which of the following statement is correct?

a) A magnetic field exerts a force on-line conductor
b) The cause of force effect lines in the fact that original magnetic field and that of line
conductor affected each other
c) The repulsion takes place in the direction of mutually reducing field forces
d) All the above statements are correct
Ans: (d)
274. Which of the following transformer will have smallest size with same electrical
specifications?
a) Oil Natural Air Natural (ONAN) cooled transformer
b) Dry type transformer
c) Oil Natural Air Force (ONAF) cooled transformer
d) Oil Forced Water Force (OFWF) cooled transformer
Ans: (b)
275. Which of the following Indian Standards deal with Induction motors?
a) IS: 2026
b) IS: 325
c) IS: 2208
d) IS: 3427
Ans: (b)
276. 1 H.P. is equivalent to

a) 0.746 W
b) 0.746 kW
c) 7.46 W
d) 7.46 kW
Ans: (b)
277. What kind of bushings will be used in the transformers above 33kV rating?
a) Porcelain type
b) Condenser type
c) Oil-filled type
d) (b) or (c)
Ans: (d)
278. If the percentage reactance of a power is 5.0, what will be the per unit reactance?
a) 0.05
b) 0.4
c) 1.0
d) 0.5
Ans: (a)
279. The eddy current loss in the transformer occurs in the

a) Primary winding
b) Secondary winding
c) Laminations
Ans: (c)
280. A transformer with output of 250 kV at 3300 volts, has 1000 turns on its primary
winding and 100 turns on secondary winding. What will be the transformation ratio the
transformer?
a) 10
b) 4
c) 5
d) 3
Ans: (a)
281. In the Q. 280, what will be the primary rated voltage of the transformer?
a) 33,000 V
b) 1650 V
c) 16,500 V
d) 1500 V
Ans: (c)
282. The speed-torque characteristics for single-phase induction motor shown below are for
a) Shaded pole motor
b) Split phase motor
c) Capacitor-start motor
d) Repulsion-start run motor
Ans: (c)
283. The induced e.m.f. in one phase of the rotor winding is 120 V when the rotor is blocked
and, the resistance and reactance per phase of stator winding are 0.2 Ω and 0.3 Ω
respectively. What will be the rotor current?
a) 330 A
b) 332 A
c) 250 A
d) 200 A
Ans: (b)
284. A circuit for the auto transformer is shown below. The point b is located half way
between terminals a and c. The resistance of entire winding is 0.1 ohm, and the resistance of
the position bc is 0.40 ohm. What will be the copper loss at an output of 10 A when the
exciting current is neglected?
a) Watts
b) 2.5 Watts
c) 10 Watts
d) 4 Watts
Ans: (b)
285. In the figure of Q. 284, if the reactance of part ab is 0.2 ohm and that of common part is
0.1 ohm, what will be the input current if primary voltage is 20 V?
a) 60 A
b) 33.3 A
c) 63.3 A
d) 30 A
Ans: (c)
286. What will wattmeter indicate is connected across supply line in the figure of Q. 284,
provided V1 = 20 V and reactance of ab is 0.2 ohm, reactance of common part is 0.1 ohm and
the core loss is neglected
a) 200 Watts
b) 100 Watts
c) 500 Watts
d) 400 Watts
Ans: (d)
287. A series motor has 2 poles and 95 turns per pole. The resistance of 2 field coils
connected in series is 3.02 ohms. The voltage drop across the field is 62 V and current is 3.55
A at 60 Hz. What will be the field reactance?
a) 27 ohms
b) 60 ohms
c) 17.2 ohms
d) 68 ohms
Ans: (c)
288. The armature winding of repulsion motor is excited

a) Conductively
b) Inductively
c) Resistively
Ans: (b)
289. The armature winding of series motor is excited

a) Conductively
b) Inductively
c) Resistively
Ans: (a)
290. Which of the following parameters contributes to the friction loss in the alternators?
a) Temperature
b) Lubrication of bearings
c) Load variation
d) Velocity of the shaft
e) All above parameters
Ans: (e)
291. The difference between input and I2Rloss will give the
a) Friction loss
b) Windage loss
c) Core loss
d) Sum of (a), (b) and (c)
Ans: (d)
292. The friction, winding and core losses of alternator can easily be determined by
a) Running the alternator at synchronous speed
b) Running the alternator as a synchronous motor at rated speed at full load
c) Running the alternator as a synchronous motor at rated speed at no load
Ans: (c)
293. The eddy-current loss in the alternator will be minimum if the air gap
a) Between poles and the slots of the armature is large compared to width of the slot
b) Between poles and the slots of the armature is minimum compared to width of the slot
c) Does not exist
Ans: (a)
294. Eddy current losses in the alternator are

a) Dependent on the load
b) Independent of the load
c) Dependent on the excitation
d) (b) and (c) both
Ans: (d)
295. The skewing of the rotor bars of the induction motor

a) Will reduce the induced voltage in each bar to a value less than if the base were
unskewed
b) Will increase the induced voltage in each bar to a value more than if the bars were
unskewed
c) Increases the cogging
d) Increases the motor noise
Ans: (a)
296. Which of the following motors have almost constant speed over their full load
range?
a) DC series motors
b) AC series motors
c) DC shunt motors
d) Low resistance squirrel cage motors
e) (c) and (d) both
Ans: (e)
297. If two wound-rotor induction motors are arranged so that the stator of one is connected
to an external source and its rotor output is connected to the other, what will be the input
conditions for the other induction motor?
a) The second motor will run at its own slip but at voltage of first motor
b) The second motor will run at slip frequency and voltage of first motor
c) The second motor will run
d) The second motor will act as frequency converter
Ans: (b)
298. In the Q. 297, the first motor acts as

a) Voltage converter
b) Frequency converter
c) Current converter
d) Power converter
Ans: (b)
299. In the Q. 297, the slip frequency of the second motor

a) Is the difference between its applied frequency and its frequency of rotation
b) Is the difference between of slip-frequency first motor and its frequency of rotation
c) (a) or (b)
Ans: (c)
300. Four speed-torque curves are shown below, which of the curve is drawn for repulsion
start induction run
a) A
b) B
c) C
d) D
Ans: (a)
301. The torque developed in D.C motor depends on

a) Armature Current
b) Magnetic field
c) Magnetic field and Magnetic Current
d) Speed
Ans: (c)
302. The speed regulation of D.C. motor can be ideally achieved with
a) Variable excitation to the field of the motor
b) Constant excitation to the field of the motor
c) A.C. excitation to the field of the motor
d) No excitation to the field of the motor
Ans: (b)
303. If the excitation to the field of the D.C. motor is constant then the torque developed in
the motor is proportional to
a) Armature current
b) Field current
c) Speed
d) Magnetic flux
Ans: (a)
304. For which of the following machine residual magnetism is a requirement to build up
voltage output?
a) Separately excited generator
b) Self-excited generator
c) All A.C. generators
d) None of them
Ans: (b)
305. What will happen to the d.c. generator if the field winding attains the critical resistance?
a) It will generate maximum voltage
b) It will generate maximum power
c) It will not develop voltage at all
d) None of them
Ans: (c)
306. Which of the following conditions hold true for paralleling two d.c. generators ?
a) Their polarities must match
b) Their phase sequence must match
c) Their polarities and voltages must match
d) (b) and (c) both
Ans: (c)
307. The armature voltage control is suitable if the d.c. machine is driven at
a) Constant current
b) Constant torque
c) Constant speed
d) Constant magnetic field
Ans: (b)
308. Which of the following parameter to achieve the variable speed of d.c. drive ?
a) Magnetic field
b) Armature resistance
c) Voltage
Ans: (c)
309. The Ward Leonard method of speed control of d.c. machin controls the speed below or
above normal speed in clockwise and anti-clockwise directive.
a) True
b) False
Ans: (a)
310. Which of the following motor one will choose to drive the rotory compressor?
a) Universal motor
b) Synchronous Motor
c) D.C. series motor
d) D.C. shunt motor
Ans: (b)
311. The electric current in the motor generator
a) Heat only
b) Magnetic field only
c) (a) and (b)
d) Power only
Ans: (c)
312. Which of the following machine will be preferred to charge the batteries?
a) Series generator
b) Series motor
c) Shunt generator
d) Compound generator
e) Shunt motor
f) None of the above
Ans: (c)
313. If the speed of a d.c. shunt motor is increased, the back emf of the motor will
a) Decrease
b) Increase
c) Remain same
d) Increase then decrease
Ans: (b)
314. The large number of slots in induction motor

a) Provides better overload capacity
b) Reduces overload capacity
c) Provides bigger size of motor
d) Reduces the size of motor
Ans: (a)
315. The good power factor of an induction motor can be achieved if the average flux density
in air gap is
a) Large
b) Small
c) Infinity
d) Absent
Ans: (b)
316. Why the d.c. motors are preferred for traction applications?
a) The torque is proportional to armature current.
b) The torque is proportional to square root of armature current.
c) The speed is inversely proportional to the torque and the torque is proportional to
square of armature current.
d) Torque and speed are inversely proportional to armature current.
Ans: (c)
317. Which of the following generating machine will offer constant voltage on all loads?
a) Separately excited generator
b) Self-excited generator
c) Level compound generator
d) All the above machines
Ans: (c)
318. The d.c. generator will be preferred if it has

a) 100% regulation
b) Small
c) 10% regulation
d) Infinity
Ans: (b)
319. The number of bushings in a transformer can be reduced if

a) The tapping are provided at the phase ends
b) The tapping are provided at the high voltage side
c) The tapping are provided in middle of the transformer
d) The tapping are provided on the low voltage side
Ans: (a)
320.Which of the following transformers will use oil natural cooling with tubes?
a) 100 kVA
b) 800 kVA
c) All the above transformers
Ans: (c)
321. An induction motor with 1000 rpm speed will have

a) 2 poles
b) 6 poles
c) 4 poles
d) 8 poles
Ans: (b)
322. Which of the following equipment will draw the reactive power?
a) Electrical iron
b) Tubelight
c) Three phase motor
d) rectifier
Ans: (c)
323. The large number of narrow slots in stator of an a.c. motor is preferred because
a) It is easier to make narrow slots than wide open slots
b) Large number of narrow slots reduces motor noise
c) Large number of narrow slots reduces noise and tooth pulsation losses
d) It helps in uniform distribution of flux
Ans: (c)
324. The number of parallel paths in wave winding of machine is

a) 4
b) 6
c) 2
d) 8
Ans: (c)
325. The alternators are normally designed for the torque angle of the order of
a) 3° to 5°
b) 2 rad to 3 rad
c) 15° to 30°
d) 1° to 3°
Ans: (d)
326. Which of the material is used to insulate the segments of commutator?
a) Fibre glass
b) Plastic
c) Mica
d) PVC
Ans: (c)
327. The brushes of electrical machines are made of

a) Carbon
b) Copper
c) Cast iron
d) Steel
Ans: (a)
328. If the resistance of the field winding of d.c. generator is increased, then the output
voltage
a) Increases
b) Decreases
c) Remains constant
d) Decreases proportional the resistance of field winding
Ans: (a)
329. Which of the following generation will be preferred if they are required to be run in
parallel ?
a) Series generators
b) Shunt generators
c) Shunt and series generators
d) Compound generators
Ans: (b)
330. To separately excited motors have

a) Excitation which is independent of load current
b) The advantage over self excited motor that it can be utilised for zero volt to its
maximum rated capacity
c) A and b both
Ans: (c)
331. The armature voltage control of dc motor will provides

a) Constant current drive
b) Constant voltage drive
c) Constant torque drive
d) Constant torque drive
Ans: (d)
332. The field current control of d.c. shunt motor will provide
a) Constant current drive
b) Constant voltage drive
c) Constant HP drive
d) Constant torque drive
Ans: (a)
333. Which of the following method of speed control of d.c. machine will offer minimum
efficiency?
a) Armature control method
b) Field control method
c) Voltage control method
d) All above methods
Ans: (a)
334. In which of the following methods of speed control computation is unsatisfactory?

a) Field control method
b) Armature current control method
c) Voltage control method
d) All above method
Ans: (a)
335. The dynamic braking can be used for

a) Series motors
b) Shunt motors
c) Compound motors
d) All above motors
Ans: (d)
336. The plugging gives the

a) Smallest torque breaker
b) Highest torque breaker
c) Zero torque breaker
d) None of them
Ans: (b)
337. Which of the method of breaking will be selected if the highest braking torque is
required?
a) Plugging
b) Dynamic braking
c) Counter breaking
d) Regenerative braking
e) (a) or (c)
Ans: (e)
338. If the terminals of armature of d.c. machine are interchanged, this action will offer
following kind of braking.
a) Plugging
b) Regenerative
c) Dynamic braking
d) Any of the above
Ans: (a)
339. If a d.c. motor for 45°C ambient temperature is to be used for 55°C ambient
temperature, then the motor
a) Is to be derated by a factor recommended by manufacturer and select next higher HP
motor
b) Can be used for 55°C ambient also
c) Of lower HP should be selected
d) Of high speed should be selected
Ans: (a)
340. If we have to control the speed of 150 HP d.c. motor from zero to 1000 rpm having rated
speed of 1500 rpm. Then it will be preferred to
a) Select a motor of 150 HP, 1500 r.p.m.
b) Select a motor of 1.5 × 150 HP, 1500 r.p.m.
c) Select a motor of 150 HP, 750 r.p.m.
d) Select a motor of 75 HP, 1500 r.p.m.
Ans: (b)
341. For which of the following alternators, the distribution factor will be 0.96?
a) Three phase alternator, 4 pole wound on 72 slots core

b) Three phase alternator, 8 pole wound on 80 slots core
c) Three phase alternator, 8 pole wound on 72 slots core
d) Three phase alternator, 6 pole wound on 72 slots core
Ans: (c)
342. Which of the synchronous alternators will complete 1080 electrical degrees in one
revolution?
a) 8 pole synchronous alternator
b) 6 pole synchronous alternator
c) 4 pole synchronous alternator
d) 10 pole synchronous alternator
Ans: (b)
343. How many cycles of alternating current will be generated in one revolution of 8 pole
synchronous alternator?
a) 10 cycles
b) 4 cycles
c) 8 cycles
d) 16 cycles
Ans: (b)
344. How many poles will be required if an alternator runs at 1500 rpm and given frequency
of 50 Hz?
a) 8 pole
b) 6 pole
c) 4 pole
d) 2 pole
Ans: (c)
345. Two generators are running in parallel. One of the generator may run as motor for
following reasons?
a) The speed of that generator is increased
b) The direction that generator is reversed
c) The generator takes large share of loads
d) The field of that generator is weakened
Ans: (c)

a) A single phase induction motor has very high starting torque.
b) A single phase induction motor has zero starting torque.
c) A single phase starting torque is as good as that of 3 phase induction motor.
d) A single phase motor has very small torque but greater than zero.
Ans: (b)
347. The primary applied voltage in an ideal transformer on no load is balanced by

a) Primary induced emf
b) Secondary induced emf
c) Secondary voltage
d) Core and copper losses
Ans: (b)
348. The air cores in transformers are preferred for

a) Low frequency transformers
b) High frequency transformers
c) 5 kVA, 50 Hz transformers
d) None of these
Ans: (b)
349. The synchronous motor can be made self starting by providing.

a) Damper winding on rotor poles
b) Damper winding on stator
c) (a) or (b)
Ans: (a)
350. The amplidyne is

a) Fully compensated cross field machine
b) Half compensated cross field machine
c) Over-compensated cross field machine
d) Under-compensated cross field machine
Ans: (a)
1.The torque produced in a wattmeter is proportional to
a) The average value of current in the two coils

b) The r.m.s. value of currents in the two coils
c) The average value of the supply voltage
Ans: (b)
2.The Dielectric heating is used for heating the

a) Wood
b) Steel billets
c) Zinc cells
d) Furnace
Ans: (a)
3. To measure the e.m.f. of a Weston standard cell one would use

a) A moving coil voltmeter
b) A hot wire voltmeter
c) An electrostatic voltmeter
d) Galvanometer
e) Potentiometer
Ans: (e)
4. Which would be large as regards the space occupied?

a) 1 ohm. 54 watt resistor
b) 500 ohms, 5 watt resistor
Ans: (a)
5. Which of the following is the best conduct?

a) Copper
b) Aluminium
c) Silver
d) Iron
Ans: (c)
6. The resonant frequency of R-L-C circuit can be changed

a) By changing inductance only
b) By changing inductance or capacitance
c) By changing resistance only
d) By changing capacitance only
Ans: (b)
7. The Dielectric loss can be measured by

a) Energymeter
b) Wheatstone bridge
c) Electrostatic wattmeter
Ans: (c)
8. The design of Inductance coil is desirable for

a) Low time constant
b) High time constant
c) Zero time constant
d) R-C time constant
Ans: (b)
9. Three-phase four-wire energymeter is used to measure

a) Three-phase balanced energy
b) Three-phase unbalanced energy
c) Single-phase energy
d) Two-phase energy
Ans: (b)
10. The potentiometer can be used to measure the current.

a) True
b) False
Ans: (a)
11. The ampere-hour efficiency of a cell does not take into account the varying voltage
of charge and discharge.
a) True
b) False
Ans: (a)
12. Watt-hour efficiency of a cell is always less than ampere-hour efficiency because
a) It takes into account the varying voltage of charge and discharge
b) Charge volts are constant
c) Discharge volts are constant
d) Polarization is neglected
Ans: (a)
13. The capacity of a cell is measured in

a) Ampere
b) Volts
c) Ampere-hours
d) Watts
Ans: (c)
14. The capacity of a cell increase as the temperature increases.

a) True
b) False
Ans: (a)
15. The gassing is the phenomenon which occurs in

a) Oil transformers
b) Cells
c) Mercury are rectifier
d) Oil cylinders
Ans: (b)
16. The ampere-hour efficiency of a lead acid cell is

a) 80%
b) 90 to 95%
c) 72 to 80 %
d) 85%
Ans: (b)
17. The gravity controlled instruments have scales which are not uniform but crowded
because
a) Balance weight is more than control weight
b) Current is proportional to deflection angle
c) Current is proportional to sin⁡ θ, where θ is deflection angle
d) Balance weight itself is not uniform
Ans: (c)
18. Which of the following instrument will be used to measure alternating current?
a) Moving iron voltmeter
b) Permanent Magnet type ammeter
c) Induction type ammeter
d) Moving iron (attraction type) ammeter
Ans: (d)
19. Eddy current damping cannot be used for moving iron instrument because
a) The size of the instrument will increase
b) Eddy currents will pass through the iron and thereby causing loss
c) The presence of a permanent magnet required for such purpose would affect the
defection and hence the reading of the instruments
d) Weight of instrument will increase
Ans: (c)
20. The deflection of a hot wire instrument depends on

a) Instantaneous value of alternating on
b) Average value of current
c) R.m.s. value of alternating current
d) voltage
Ans: (c)
21. Which of the following instruments will be used measure 500 kV a.c. voltage ?
a) Moving coil voltmeter

b) Electrostatic voltmeter
c) Moving iron voltmeter
d) Hot wire instrument
Ans: (b)
22. The steady speed of the disc in the energymeter is achieved when
a) Operating torque is to braking torque
b) Operating torque is half of the braking torque
c) Breaking torque is zero
d) Braking torque is more than operating torque
Ans: (a)
23. Creeping is the phenomenon which occurs in

a) Voltmeter
b) Wattmeter
c) Energymeter
d) Ammeter
Ans: (c)
24. The induction type signal phase energymeter is

a) An ampere-hour meter
b) True watt-hour meter
c) Wattmeter
d) VAR meter
Ans: (b)
25.Two holes are drilled in the disc of energymeter on the opposite side of the spindle
a) To reduce the weight of the disc for easy rotation
b) To eliminate creeping on no load
c) For proper ventilation
d) To increase the deflection torque
Ans: (b)
26. Given three methods of localizing the short circuit fault fault in the cables
a) Murray loop test
b) Varley loop test
c) Fisher loop test
Ans: ()
27. This induction method of testing which is used for localization of ground faults in cables
can be applied successfully when the cables has metallic sheath.
a) True
b) False
Ans: (a)
28. Which of the following instruments will be used to measure the temperature above 1400
degree centigrade?
a) A simple thermometer pyrometer
b) Electrical resistance pyrometer
c) Thermo-electric pyrometer
Ans: (c)
29. The temperature coefficient of carbon is negative.

a) True
b) False
Ans: (a)
30. Given the name of three-thermo junctions

a) Copper-constantan
b) Silver-constantan
c) Iron-constantan
Ans: ()
31.The thermo-electric e.m.f. of platinum with platinum-rhodium (alloy) at 500 degree

centigrade is
a) 7.4 millivolts
b) 4.4 millivolts
c) 5 millivolts
d) 1 millivolts
Ans: (b)

a) Alternating current and voltage waveforms do not in general, contain even harmonics
b) Alternating current and voltage waveforms in general do not contain odd harmonics
c) Alternating current and voltage waveforms in general contain even harmonics
d) Alternating current and voltage waveforms contain even and odd harmonics in
general
Ans: (a)
33. The shape of the waveform when, an e.m.f. whose wave contains harmonics is applied to
a circuit, is not, in general, the same as that of impressed e.m.f. wave but depends upon the
resistance, capacitance and inductance.
a) True
b) False
Ans: (a)
34. The inductance in the circuit

a) Reduces the amplitude of harmonics in current wave
b) Enlarges the amplitude of harmonics in current wave
c) Does not effect the wave shape at all
d) Reduces the amplitude of the harmonics in the current wave and causes the latter to
approach more nearly to the sinusoidal wave shape than e.m.f. wave
Ans: (a)
35. The e.m.f. whose wave contains harmonics is applied to resistive circuit, the current
waveform is of the same form as that of the impressed e.m.f.
a) True
b) False
Ans: (b)
36. The resonance effect can be used to ascertain whether any particular harmonics exists in
an e.m.f. waveform or not.
a) True
b) False
Ans: (a)
37. The power factor of a circuit in which voltage and current waves are non-sinusoidal
requires the following definition
a) It is the cosine of the angle of phase difference between the voltage and current
waves
b) It is the cosine of the angle of phase difference between the two complex wave
c) It is the cosine of the angle of phase difference between two “equivalent sine waves”
having respectively r.m.s. values equal to those of the voltage and current in the circuit
d) It is the sine of the angle of phase difference between the two complex waves
Ans: (c)
38. The electron beam in the cathode ray oscilloscope may be deflected by
a) Electrostatic field only
b) Electromagnetic field only
c) (a) or (d)
Ans: (c)
39. The temperature at which the readings of Fahrenheit and Centigrade thermometer are the
same is
a) Zero
b) 25° C
c) -40° C
d) 32° C
Ans: (c)
40. The alloying element which really makes the steel corrosion resistant is
a) Chromium
b) Magnesium
c) Nickel
d) Molybdenum
Ans: (c)
41. The resistance of the coil of 1000 watt, 250 V electric lamp is
a) 2.5 ohms
b) 6.25 ohms
c) 62.5 ohms
d) 625 ohms
Ans: (c)
42. The rating of the batteries is given by

a) KW
b) Ampere-house
c) KVA
d) VARH
Ans: (b)
43. A moving coil instrument can be used to measure

a) Low frequency alternating current
b) High frequency alternating current
c) Direct current
d) Direct current and alternating current both
Ans: (c)
44. The cost of a capacitor increase as

a) The size of a capacitor increase
b) Voltage rating of the capacitor increases
c) Microfarad rating of the capacitor increases
Ans: (b)
45. A 100 microfarad, 200 V capacitor will have larger size than the 10 microfarad, 200 V
capacitor.
a) True
b) False
Ans: (b)
46. The thermal time constant is the time

a) To reach the final steady temperature if the initial rate of increase of temperature were
maintained constant
b) To reach 63% of fined steady temperature
c) To reach 86.6% of final steady temperature
d) To reach 37% of final steady temperature
Ans: (a)
47. The current transformer can also be used to measured high d.c. current.
a) True
b) False
Ans: (b)
48. Two voltmeters are connected in series. The atomic weight of Ag and Cu are 108 and 64
respectively. If 0.5 gm of copper is deposited in one voltmeter than mass of silver deposited
in the second will be
a) 0.5 × 108/64 gm
b) 0.5 × 64/108 gm
c) 0.5 × 108/32 gm
d) 0.5 × 32/108 gm
Ans: (c)
49. The secondary of the current transformer is always short circuited through low resistance
ammeter or low resistance
a) To get accurate measurement
b) To avoid excessive current in the primary
c) To avoid the risk of high voltage because the unopposed primary m.m.f. will set up an
abnormally high flux in the core which produces excessive core less with high heating
and a high voltage across the secondary of the transformer
d) Because the current in the primary is not determined by load in primary
Ans: (b)
50. The current in the primary of the potential transformer is determined by the load in
primary.
a) True
b) False
Ans: (b)
51. A 100: 5 transformer is used in conjunction with a 5 amp ammeter. If latter reads 2.5
amps the line current will be
a) 2.5 × 100/5 amps

b) 2.5 × 5/100 amps
c) 2.5 × (5/100)2
d) 2.5 × (100/5)2
Ans: (a)
52. Which of the following circuit has no transients?

a) Pure resistive circuit
b) L-C circuit
c) R-L-C circuit
d) R-L circuit
Ans: (a)

a) A galvanometer with low resistance in series is an ammeter
b) A galvanometer with high resistance in series is an ammeter
c) A galvanometer with high resistance in parallel is a voltmeter
d) A galvanometer with low resistance in parallel is a voltmeter
Ans: (a)
54. A voltage source can be converted into constant current source by adding
a) Low resistance in parallel with the voltage source
b) High resistance in parallel with the voltage source
c) Low resistance in series with the voltage source
d) High resistance in series with the voltage source
Ans: (d)
55. permeability in the magnetic circuit is analogous to

a) Resistance in electrical circuit
b) Resistivity in electrical circuit
c) Conductivity in electrical circuit
d) Current density
Ans: (c)

a) 1 volt = 1 wb
b) 1 volt = 1 wb/second
c) Volt has no relation with Weber
d) 1 volt = 1 wb-second
Ans: (b)
57. A conductor of length 100 cm moves right angle to a magnetic field of flux density of 2
wb/m2 with the velocity of 25 m/second. The induced e.m.f. in the conductor will be
a) 25 volts
b) 50 volts
c) 75 volts
d) 100 volts
Ans: (b)
58. The ratio error in the current transformer is attributed

a) Wattles component of the current in the primary
b) Exciting current
c) Power factor of the primary
d) Leakage flux
Ans: (b)
59. The phase angle error of current transformer is of no importance if it is feeding an

ammeter.
a) True
b) False
Ans: (a)
60. Wheatstone bridge is analogous to

a) Cantilever
b) Simple level system
c) Gear train
d) Mechanical clutch
Ans: (b)
61. The bring by which inductance is measured in terms of capacitance and resistance is
called
a) Maxwell-Wein bridge
b) Wein bridge
c) Anderson bridge
d) Schering bridge
Ans: (c)
62. The dielectric loss of capacitance can be measured by

a) Owen bridge
b) Schering bridge
c) Wein bridge
d) Maxwell bridge
Ans: (b)
63. A television receiver used 240 watts from 60 volts power source
a) 2 ma
b) 2 amps
c) 240 amps
d) 60 amps
e) 4 amps
Ans: (e)
64. The difference between power and energy is that

a) Power is the time rate doing work while the energy does not involve time
b) Energy is the time rate of doing work while the power does not involve time
c) Energy is V × I without taking time into account
d) Power can be measured in watt-hours where energy cannot
Ans: (a)
65. If one ampere current is allowed to accumulate charge for 5seconds, the resultant change
equals
a) 2 coulombs
b) 10 coulombs
c) 5 amps
d) 10 amps
e) 5 coulombs
Ans: (e)
66. A 50 micro-ampere meter movement has 500 ohms resistance, what shunt resistance is
required to extend the range to 250 micro-ampere?
a) 111.1 ohms
b) 125 ohms
c) 250 ohms
d) 50 ohms
Ans: (b)
67. To connect ammeter in series

a) Open the circuit at one point and use the meter to the circuit
b) Open the circuit at the positive and the negative terminals of the voltage source
c) Short the resistance to be checked and connect the meter across it
d) Open the circuit at one end connect the meter to one end
Ans: (a)
68. A voltmeter using 50 micro-ampere meter movement has a sensitivity of

a) 500 ohms per volt
b) 5000 ohms per volt
c) 2000 ohms per volt
d) 20,000 ohms per volt
Ans: (d)
69. To connect the voltmeter in parallel to read IR drop

a) Open the circuit at one and use the meter to complete the circuit
b) Open the circuit at two points and connect the meter across both points
c) Let remain the circuit as it is and connect the mater across the resistance
d) Allow the circuit to remain closed but disconnect the voltage source
Ans: (c)
70. The shunt used in the milliameter

a) Will extend the range and reduces the meter resistance
b) Will extend the range and increases the resistance
c) Will decrease the range and meter resistance
d) Will decrease the range but increases the inter resistance
Ans: (a)
71. To check the continuity of the circuit by multimeter, the best of the following ranges
to use is R ×
a) 1,000
b) 10,000
c) 100,000
d) 1
Ans: (d)
72. The applied voltage is to the circuit being checked is disconnected when an ohmmeter is
used because
a) The voltage source will increase the resistance
b) The current will decrease the resistance
c) The ohmmeter has its own battery
d) No current is needed for matter movement
Ans: (c)
73.When the voltage is measured by a multimeter, the multiplier for voltage is

a) A high resistance in series with the meter movement
b) A high resistance in parallel with the meter movement
c) Less than one ohm in series with the meter movement
d) Less than one ohm in parallel with the meter movement
Ans: (b)
74. A VTVM has negligible loading effect on the circuit being cheeked because it has
a) A high resistance range of R × 1 M Ω
b) High input resistance of 11 MΩ or more
c) Low current ranges of 59 micro-ampere or less
d) Low input resistance equal to the lowest value on the R × 1 range
Ans: (b)
75. The Wheatstone bridge is used to measure

a) Low value of current
b) High value of current
c) High value of voltage
d) Low value of voltage
e) Resistance value
Ans: (e)
76. The insulating materials are used to

a) Conduct very large current
b) Present an open circuit between the voltage source and the load
c) Prevent short circuit between conducting wires
d) Store very high currents
Ans: (c)
77. The internal resistance of the milliammeter must be very low for
a) High sensitivity
b) High accuracy
c) Maximum voltage drop across the meter
d) Minimum effect on the current in the circuit
Ans: (d)
78. The internal resistance of the voltmeter must be very high in order to have
a) High voltage range
b) Minimum current through the meter
c) Maximum loading effect
d) More current supplied by the voltage source
Ans: (d)
79.The total flux of 5000 lines equal

a) 1,26 gilberts
b) 5,000 gauss
c) 5,000 maxwells
d) 16,000 kilolines
Ans: (c)
80. The flux of 4,000 lines through 4 cm2 equals a flux density of

a) 1,000 gauss
b) 2,000 gauss
c) 4,000 gauss
d) 16,000gauss
Ans: (a)
81. The flux density of 2000 gauss equals
a) 2,000 lines per cm2

b) 2,000 lines per cm2
c) 2,000 kilolines per cm 2
d) 400,000 lines per cm2
Ans: (b)
82. In ohm’s law for magnetic circuit

a) M.m.f. corresponds to current
b) Gilbert corresponds to volt
c) Reluctance corresponds to ampere
d) Gauss corresponds to ohm
Ans: (b)
83. In the given circuit how much the voltmeter will read ?
a) 0 volt
b) 10 volts
c) 4 volts
d) 5 volts
e) 3.33 volts
Ans: (e)
84. A voltage source and a voltmeter have

a) Zero and ideally infinity zero input impedance respectively
b) Ideally infinite and zero input impedances respectively
c) High and low input impedances respectively
Ans: (a)
85. The r.m.s. value of the following half wave with its maximum, Imax is
a) Imax/2
b) Imax/√2
c) Imax
d) Imax/√3
Ans: (a)
86. Which of the following instrument will be used to measure a very high frequency but
small current ?
a) Electrodynamic ammeter
b) Moving coil galvanometer
c) Thermocouple type instrument
d) Induction type instrument
Ans: (c)
87. If n identical cell of e.m.f. E and internal resistance r are connected in series, they produce
a current though an external resistance R equal to
a) nE/R + r
b) nE/R
c) nE/r + n.r
d) E/R + r
Ans: (c)
88. The hysteresis and eddy current are used for

a) Dielectric heating
b) Induction heating
c) Wood heating
Ans: (b)
89.A dielectric between the plates of a capacitor

a) Decreases the capacitance
b) Increases the capacitance
c) Provides the strength to the capacitor plates
Ans: (b)
90. A rectifier type a.c. voltmeter

a) Generally uses the iron-vane type of a.c. movement
b) Has a linear scale because it uses a.d.c. meter movement
c) Has a none-linear scale crowded at the left because it uses the dynamometer type of
meter movement
d) Needs a thermocouple for low frequencies
Ans: (b)
91. The wattmeter
a) Has voltage and current coils to measure the real power

b) Has three connections two of which are used at a time
c) Measures apparent power because the current is same in the voltage and current
coils
d) Can measure d.c. power but not 60 cps a.c. power
Ans: (a)
92. Which of the following statement is true ?

a) The hysteresis loss can be determined from the area of B-H curve
b) Eddy current loss is determined from the area of B-H curve
c) Hysteresis and eddy current losses can be determined from the area of the B-H loop
d) None of the above losses is determined from the B-M loop
Ans: (a)
93. The damping of the ballistic galvanometer is kept very small

a) To make the system oscillating
b) In order to get first deflection large
c) In order to get first deflection small
d) To make the system critically damped
Ans: (b)
94. The grosset fluxmeter is special type of ballistic galvanometer in which

a) Controlling torque is small and damping is heavy
b) Controlling torque and damping are large
c) Controlling torque is large but damping is small
d) Controlling torque and damping are small
Ans: (a)
95. Ballistic galvanometer can be used to measure the current and flux both.
a) True
b) False
Ans: (a)
96. Which of the following frequency meter is suitable to measure radio frequency ?
a) Electrical resonance frequency meter
b) Weston frequency meter
c) Heterodyne frequency meter
d) Either (b) or (c)
Ans: (c)
97. Enumerate the advantages of moving iron power factor meter over the dynamometer type
power factor meter
a) Large working forces
b) A scale which extends to 360°
c) The absence of ligaments to lead in current to moving coils, all coils in the moving iron
types being fixed
Ans: ()
98. Enumerate the sources of errors in the moving coil instruments

a) Weakening of permanent magnets due to ageing and temperature effect
b) Weakening of spring due to ageing and temperature effect
c) Change of resistance of moving coil with temperature
Ans: ()
99. Enumerate the errors in moving iron instruments with both A.C. and D.C.
a) Hysteresis error
b) Stray magnetic fields
c) Temperature error
Ans: ()
100. Enumerate the errors in moving iron ammeter with a.c. only
a) Frequency errors
b) Reactance of instrument coil
c) Eddy currents
Ans: ()
101. For a good 0.5 micro-farad paper capacitor, the ohm-meter reading should
a) Go quickly to 100 ohms and remain there

b) Show low resistance momentarily and back off to a very high resistance
c) Not move at all
d) Show very high resistance first and then low
Ans: (b)
102. Which of the following error may arise in wattmeter if it is not compensated for the
errors?
a) Voltage coil inductance
b) Voltage coil capacitance
c) Eddy currents
d) (a), (b) and (c)
Ans: (d)
103. Which of the following is methods is the commonest method of measuring three
balanced or unbalanced power?
a) One wattmeter method
b) Two wattmeter method
c) Three wattmeter method
d) Ammeter method
Ans: (b)
104. One-Wattmeter method is used to measure

a) The power when load is balance in three phase circuit
b) The power when load is unbalanced in three phase circuit
c) (a) or (b)
d) Single phase power with balanced load
Ans: (a)
105. The reactive power can be measured with wattmeter when voltage across voltage coil is
adjusted to be out of phase with the current by
a) 90°
b) 180°
c) 45°
d) 0°
e) 120°
Ans: (a)
106.The change of frequency affects the circuit parameters of wattmeter connected to

measure power of three-phase AC system
a) True
b) False
Ans: (b)
107. Which of the following devices are required to measure three phase balance power?
a) One wattmeter
b) One wattmeter and one voltage transformer of 1:1 ratio
c) One wattmeter and two current transformers of 1:1 ratio
d) Either (b) or (c)
Ans: (d)
108. The total power P measured in Y star three-phase circuit is given by

a) P = 3VI cos ⁡ϕ
b) P = √I cos ⁡ϕ
c) P = √3VI cos ⁡ϕ
d) P = √2VI cos⁡ ϕ
Ans: (c)
Where V and I are the line voltage and line current respectively.
109.In the above question, the power in delta three-phase circuit is given by
a) P = 3 VI cos ⁡ϕ
b) P = √3 VI cos ⁡ϕ
c) P = √2 VI cos ⁡ϕ
d) P = √3 VI sin ⁡ϕ
Ans: (b)
110. The dynamometer wattmeter can be used to measure

a) AC power only
b) DC power only
c) AC or DC power
d) AC power of single-phase circuits
Ans: (c)
111.The pointer deflection of wattmeter is proportional to
a) Torque produced in the wattmeter b) Voltage

c) Current
d) Power
e) (a) or (b)
Ans: (e)
112. Induction wattmeters can be used to measure

a) AC power
b) DC power
c) AC or DC power
d) AC power of single phase only
Ans: (a)
113. Motor meters can be used to measure AC or DC

a) Watt-hours
b) Ampere-hours c) Current
d) Voltage
e) (a) or (b)
Ans: (c)
114. Motor meter can be used to measure

a) AC energy
b) DC energy
c) AC or DC energy
Ans: (d)
115. The one “unit” of energy measured in AC circuit is equivalent to

a) One watt-hour
b) One kilowatt-hour
c) One watt
d) One kilowatt
e) One joule
Ans: (b)
116. Which of the following energy meter is universally accepted to measure AC encrgy?
a) Motor meter
b) Induction type meter
c) Mercury motor meter
d) Reason Electrostatic meter
Ans: (b)
117. Which of the following loads are dangerous for thermal heating of wattmeter even if
meter reading is low?
a) Loads with high value of power factor
b) Loads with low value of power factor
c) Chokes
d) (b) and (c)
Ans: (d)
118. The eddy current torque on a metallic disc rotating between poles of permanent magnet
in energy meter is directly proportional to the angular velocity of the disc.
a) True
b) False
Ans: (a)
119. If the reading of two wattmeters in two-wattmeter method of power measurement are 4
kW and 3 kW respectively and the latter reading being obtained after reversing connection of
the current coil of wattmeter, what will be the power?
a) 6 kW
b) 1 kW
c) 4 kW
d) 5 kW
e) 7 kW
Ans: (b)
120.An AC potentiometer can be used to measure the loss in an iron ring made up of thin
stampings.
a) True
b) False
Ans: (a)
21. Which of the thermocouple one will choose to measure the temperature of 500°C?
a) Chromal Alumal (Cr Al)

b) Iron Constantan (Fe K)
c) Platicum-Platinum Rhydium (Pt Pt Rh)
Ans: (b)
122. Cr Al thermocouple can be used to measure the temperature upto

a) 500° C
b) 800° C
c) 1200° C
d) 1800° C
Ans: (c)
123. The output of thermocouple is in the range of

a) Volts
b) Millivolts
c) Amperes
d) Milliamperes
Ans: (b)
124.A resistance temperature detector (RTD) is used to sense the temperature. Which of the
following converter will be used to receive a milliampere signal from RTD ?
a) MU/MA Converter
b) A/MA Converter
c) R/MA Converter
Ans: (c)
125. A moving iron instrument will not given erroneous reading upto frequency upto
a) 1000 Hz
b) 1500 Hz
c) 2000 Hz
d) 5 kHz
Ans: (d)
126. Which of the following device is used to measure the leakage resistance of a capacitor ?
a) Schering bridge method
b) Megger
c) Potentiometric bridge
d) Loss of charge method
Ans: (d)
127. Eddy current error does not exist in

a) DC moving iron instruments
b) AC moving iron instruments
c) (a) and (b) both
Ans: (c)
128. Capacitance cannot be measured with ballistic galvanometer.

a) True
b) False
Ans: (b)
129. The movement of the moving element of an electrical indicator is dependent of

a) Restoring torque
b) Number of turns of the coil
c) Resistance of the indicator circuit
d) (a) and (c) only
e) (a), (b) and (c)
Ans: (e)
130. The ballistic galvanometer with high oscillation period and high critical resistance will
be most suitable for the measurement of
a) Inductance
b) Voltage
c) Capacitance
d) Current
Ans: (c)
31. The internal resistance of an ammeter will be
a) Infinity
b) Zero
c) Very small
d) Large
Ans: (c)
132. The internal resistance of the voltameter is

a) Zero
b) Very high
c) Infinity
d) Very small
Ans: (b)
133. Which of the following instruments will have poorest overloading capacity?
a) Moving coil instruments
b) Induction type instruments
c) Permanent magnet instruments
d) Hotwire instruments
Ans: (d)
134. The impulse ratio of any insulator is

a) Zero
b) Unity
c) Less than unity
d) More than unity
Ans: (d)
135.The impulse ratio depends on the

a) Polarity of the impulse voltage
b) Steepness of the impulse wave-front
c) Time of decay of the impulse voltage
d) All the above
Ans: (d)
136. “The magnetic strength is inversely proportional to the distance from the conductor in
which the current flows.” The above law is known as
a) Lenz’s Law
b) Biot Law
c) Biot and Savart’s Law
d) Ampere’s Theorem
Ans: (c)
137. The value of magnetizing force H = NI/L is true for a solenoid only when
a) Radius of the solenoid is more than length
b) Radius of the solenoid is much less than its length
c) Radius of the solenoid is equal to length of the solenoid
d) Number of turns are unlimited
Ans: (b)
138.The magnetization curve is shown below. The ratio of ∆B to ∆H is known as :

a) Permeability
b) Incremental permeability
c) Flux density
d) Incremental magnetization force
Ans: (b)
139. Which of the following dimensions are for electrical charge?

a) LT-2
b) MLT-2
c) ε1/2 L3/2 M1/2 T-1
d) LT-1
Ans: (c)
140. Dimension of the current are

a) LT-2
b) MLT-2
c) ε1/2 L3/2 M1/2 T-2
d) ε1/2 L2 M-1/2 T2
Ans: (c)
141. The dimension of voltage are
a) ML2 T-2
b) ML2 T-2 Q-1
c) εLT-1
d) M1/2 L1/2 μ-1/2
Ans: (b)
142. If the dimension of work done and time are given, will it be possible to find the
dimensions of power?
a) Yes
b) No
Ans: (a)
143. The dimensions of electric energy are given by

a) L2 MT-2
b) L2 MT-3
c) LT-3 μ
d) Lμ
Ans: (a)
144. Which of the following quantity quantity has same dimension in electromagnetic and
electrostatic system?
a) Electric power
b) Electric energy
c) Current
d) (a) and (b) both
Ans: (d)
145.Which of the following outputs of the current transformers are commonly specified?
a) 1 A, 10 A
b) 2 A, 20 A
c) 1 A, 5 A
d) 0.1 A, 1 A
Ans: (c)
146. The power of 6 phase circuit can be measured with minimum

a) One wattmeter
b) Three wattmeters
c) Five wattmeters
d) Six wattmeters
Ans: (c)
147. The hot-wire instruments have more power consumption in comparison with other
electrical instruments for similar instruments.
a) True
b) False
Ans: (a)
148. Which of the following quantity is equivalent to one farad?

a) 10-9 e.m.u.
b) 10-9 e.m.u
c) 10/9 e.m.u.
d) 9/10 e.m.u.
Ans: (b)
149. The most of the voltmeters for general use are designed for the power loss of
a) 1 Watt
b) 5 Watts
c) 0.2 to 0.5 Watts
d) 10 Watts
Ans: (c)
150. Which of the following quantity is equivalent to one henry?

a) 109 e.m.u.
b) 10-9 e.m.u
c) 10/9 e.m.u
d) 9/10 e.m.u.
Ans: (a)
151. In the moving iron instruments, the torque is proportional to
a) Inductance of instruments
b) First derivative of inductance with respect to time
c) First derivative of inductance of instruments with respect to deflection angle
d) Current
Ans: (c)
152. Which of the instrument are free from hysteresis and eddy current losses?
a) Moving iron instruments
b) Electrodynameter type instruments
c) Electrostatic instruments
Ans: (c)
153. The electrostatic instruments rely for their operation upon the
a) Current
b) Voltage
c) Fact that a force exists between the two plates having opposite charges
d) Power
Ans: (c)
154. Which of the following instruments can be used to measure only A.C. currents?
a) Moving iron instruments
b) Electrodynamic instruments
c) Induction type instruments
d) Hotwire instruments
Ans: (c)
155. The permeability of magnetic circuits is analogous to

a) Current of electrical circuits
b) Voltage of electrical circuits
c) Current density of electrical circuits
d) Resistance of electrical circuits
e) Conductivity of electrical circuits
Ans: (e)
156. The current ratio of current transformers is constant under all load conditions.
a) True
b) False
Ans: (b)
157. The ratio error in the current transformers is largely dependent upon
a) Iron loss component of magnetizing current
b) Magnetizing component of the magnetizing current
c) (a) and (b) both
d) (a) or (b)
Ans: (a)
158. The material used for the core of current transformer should have
a) Low reluctance and low iron loss
b) High reluctance and high iron loss
c) Low reluctance and high iron loss
d) High reluctance and low iron loss
Ans: (a)
159. What will happen if the secondary winding of the current transformer is opened when
current is flowing in the primary current?
a) There will be high current in the secondary winding
b) There will be very high induced voltage in the secondary winding
c) There will be very weak flux density in the core
d) The transformer will burn immediately
Ans: (b)
160. Which of the secondary winding of current transformer is opened, the ampere-turns of
primary winding will
a) Increase
b) Decrease
c) Remain same
d) Be very small
Ans: (c)
161. Which of the following transformers have secondary current of same order as
magnetizing current?
a) Current transformer
b) Voltage transformer
c) Power transformer
d) Distribution transformer
Ans: (b)
162. Turns compensation in the current transformers is used to

a) Eliminate phase angle error
b) Eliminate ratio error
c) Obtain a transformation ratio more nearly equal to nominal ratio of the transformer
Ans: (c)
163. If the burden of the current transformer is 15 VA, and secondary current is 5 A. what
will be the impedance of connected load?
a) 6 ohms
b) 0.6 ohms
c) 60 ohms
d) 5 ohms
Ans: (b)
164. What will be secondary terminal voltage of the current transformer in the above Q. 163?
a) 4 V
b) 6 V
c) 3 V
d) 12 V
e) 1 V
f) 5 V
Ans: (c)
165. The inaccuracy in balancing the bridge circuit is attributed to

a) Temperature
b) Thermal e.m.f.
c) Battery of circuit
d) Resistance of the bridge
Ans: (b)
166. Which of the bridge will be used to measure the inductance in terms of the resistance
and capacitance?
a) Wein bridge
b) Schering bridge
c) Anderson bridge
d) Maxwell bridge
Ans: (c)
167. The high quality factor Q of the inductance can be measured by

a) Hay bridge
b) Anderson bridge
c) Wein bridge
d) Schering bridge
Ans: (a)
168. An additional ratio arm in the bridge circuit is used to counterbalance the
a) Leads resistance
b) Thermal e.m.f.
c) Observation errors
d) Temperature
Ans: (b)
169. The higher limit of the resistance measured by bridge method is determined by contact
resistance and resistance of connecting wires.
a) True
b) False
Ans: (b)
170. The lower limit of the resistance measured by the bridge methods is determined by the
sensitivity of the detector.
a) True
b) False
Ans: (b)
171. Which of the following is used to measure the low impedance components?
a) Series connection Q-meter
b) Parallel connection Q-meter
c) (a) or (b)
Ans: (a)
172. Which of the following is used to measure the high impedance components?
a) Parallel connection Q-meter
b) Series connection Q-meter
c) (a) or (b)
d) (a) and (b) simultaneously
Ans: (a)
173. Ballastic galvanometer can be used to measure the mutual inductance.

a) True
b) False
Ans: (a)
174. Which of the following bridge is called Wein-bridge?

a) A
b) B
c) C
d) D
Ans: (c)
175. Which of the following bridge will be used to measure the low values of resistance?
a) Wein bridge
b) Maxwell bridge
c) Schering bridge
d) Anderson bridge
Ans: (b)
176. What will happen when quartz (SiO2) crystal is compressed?

a) The size of the crystal will be reduced
b) There will be a great amount of heat because of molecules movement
c) The electrical changes will be set up across the crystal ends
d) The crystal will melt
Ans: (c)
177. The quartz (SiO2) crystal is compressed to develop the voltage across the ends, this
phenomenon is known as :
a) Voltaic effect
b) Piezo-electrical effect
c) Hall effect
d) Photo-voltaic effect
Ans: (b)
178. A switchgear control consists of

a) A main switch to isolate the apparatus from the supply
b) Fuses
c) Circuit breaker and fuses
d) Overvoltage relay
e) Interlocks and earth connections
f) (a), (c), (d) and (e)
Ans: (f)
179. The peak factor of the sinusoidal wave is defined as :

a) (r.m.s. Voltage)/(peak Voltage)
b) (Peak Voltage)/(r.m.s. Voltage)
c) (Peak Voltage)/(Average Voltage)
d) (Peak Voltage)/(d.c. Voltage)
Ans: (b)
180. In the peak voltage is to be measured by “Rectified Capacitor Charging Current

Method”, the peak voltage is given by :
a) Iaverage/(4 cf)
b) Irms/(4 cf)
c) Idc/(4 cf)
d) Iaverage/cf
Ans: (a)
181. Which of the following voltmeters can indicate peak, r.m.s. alternating and d.c. high
voltage?
a) Electrostatic voltmeter
b) Galvanometric voltmeter
c) Ionic wind voltmeter
d) Vacuum tube voltmeter
Ans: (c)
182. Following are the curves for different thermocouple. Which of the curve is drawn for
platinum-platinum Rhodium thermocouple?
a) A
b) B
c) C
d) D
Ans: (a)
183. Alundum is the name given to

a) Fused alumina
b) Fused fireclay
c) Fused alumina and fireclay
d) Fused platinum
Ans: (c)
184. The alternating current and voltage wave from do not, in general, contain even
harmonics.
a) True
b) False
Ans: (a)
185. If the voltage wave form having all odd harmonics is applied to the resistive circuit, then
the current wave form will
a) Be similar to voltage wave form
b) Be different from voltage wave from
c) Have even harmonics
d) Be sinusoidal
Ans: (c)
186. The primary winding of Ct has

a) Thicker wire than secondary winding
b) Thinner wire than secondary winding
c) Same thickness as secondary winding
d) More turns than secondary
Ans: (a)
187. The self-balancing potentiometer is used

a) For experimental purpose in the laboratory
b) For vibration measurements
c) For industrial measurements
d) In recorders
Ans: (c)
188. Which of the following bridge can be used to measure high frequency oscillations?
a) Schering bridge
b) Anderson bridge
c) Wein bridge
d) Maxwell bridge
Ans: (c)
189.Which of the method one will choose for the low resistance measurement?
a) Schering bridge method
b) Maxwell bridge method
c) Kelvin’s double bridge method
d) Potentiometric method
Ans: (c)
190. Two voltmeters each with the range of 0-100 V and resistances 40,000 Ω and 10,000 Ω
respectively are connected in series across the power supply source of 50 V. The voltmeters
will indicate
a) 40 V, 10 V respectively
b) 30 V, 20 V respectively
c) 50 V, 0 V respectively
d) 20 V, 30 V respectively
Ans: (a)
191. A rectifier type instrument is used to measure d.c. voltage of 220V. What will the
instrument indicate?
a) 220 V
b) 110 V
c) 178 V
d) 0 V
Ans: (d)
192. If a circuit has inductance of 20 H and 10 Ω resistance, after how many seconds the
current will attain 63% of the steady state value which is 24 A?
a) 20 seconds
b) 2 seconds
c) 1 second
d) 0.02 second
Ans: (b)
193. Which of the methods can be used to measure the unbalance load of three-phase system?
a) One wattmeter method
b) Two wattmeter method
c) Three voltmeter method
d) Three ammeter method
Ans: (b)
194. The one wattmeter method can only be used to measure balance load of the three phase
electric system.
a) True
b) False
Ans: (a)
195. The wattmeter is connected in the three phase balanced circuit as shown. The wattmeter
will indicate
a) Active power
b) Wattles power
c) Reactive power
d) (b) or (c)
Ans: (d)
196. The induction testing method is used to find which of the following fault in the cables?
a) Short circuit fault
b) Earth fault
c) Open circuit fault
d) (b) or (c)
Ans: (b)
197. The breakdown of the insulation of the cable will be termed as

a) Earth fault
b) Short circuit fault
c) Open circuit fault
d) (a) or (c)
Ans: (a)
198. loop tests are applied to find the

a) Ground fault of the cable
b) Open circuit fault of the cable
c) Short circuit fault of the cable
d) (a) or (c)
Ans: (d)
199. The stroboscopic method can be used to measure the rotational speed of the electrical
drives.
a) True
b) False
Ans: (a)
200.The power factor meter have

a) Only current coil
b) Only voltage coil
c) Current and voltage coils both
d) Only inductive voltage circuit
e) Only inductive current circuit
Ans: (c)
201. Which of the following instruments have poor overload capacity?

a) All electronics instruments
b) Galvanometric instruments
c) Wattmeters
d) Hot wire instruments
Ans: (d)
202. A Voltmeter should have

a) Infinite resistance
b) Very high resistance
c) Low resistance
d) Zero resistance
Ans: (b)
203. The internal resistance of an ammeter should be

a) Infinite resistance
b) Very small resistance
c) Zero resistance
d) High resistance
Ans: (b)
204. Find the odd man out.

a) Copper Constantan
b) Iron Constantan
c) Platinum-Platinum Rhodium
d) Lead Carbon
e) Nickel Chromium
Ans: (b)
205. The Quality factor meter operates on the principal of series resistance
a) True
b) False
Ans: (a)
206. Which of the following instruments have self balancing property?

a) Galvanometric type
b) Potentiometric type
c) Digital type
d) Ammeters
Ans: (b)
207. Which of the following instruments are most susceptible to vibrations?

a) Galvanometric type
b) Potentionmetric type
c) Digital type
d) Voltmeters
Ans: (a)
208. The source of reference voltage for A.C. potentiometers is a standard cell
a) True
b) False
Ans: (b)
209. Which of the following transducers offer the best accuracy?

a) Strain guage type
b) Diaphragm type
c) Capacitance type
d) Capsule type
Ans: (c)
210. The flow can be measured directly by

a) Pressure transducer
b) Differential Pressure Transducer
c) Differential Pressure transducer and Square Root Extractor
d) Pressure Switch
Ans: (c)
211. The resolution of a digital ammeter with 3 digit display is
a) 1/10000
b) 1/1000
c) 1/4
d) 1/3
Ans: (b)
212. The accuracy of measuring instruments at high frequency
a) Decrease
b) Becomes zero
c) Increases
d) Does not change
Ans: (a)
213. How many coils are required in the megger?

a) One
b) four
c) Two
d) Five
Ans: (c)
214. What will be the reading of megger if the measuring terminals are open circuited?
a) Infinity
b) 500 ohms
c) Zero
d) 10,000 ohms
Ans: (a)
215. Which of the following instrument will have same calibration on A.C. and D.C.?
b) Moving iron instruments
c) Induction type instruments
d) Electrodynamometer instruments
Ans: (d)
216. The measurement of reproducibility of an instrument given an indication of

a) Resolution
b) Damping
c) Efficiency
d) Accuracy
e) Precision
Ans: (e)
217. The internal resistance of an instrument is normally based on criterian that

a) It draws large power
b) The instrument can be connected in any circuit
c) It does not change the parameters of the circuit to which this is connected
d) It draws minimum power for its operation
Ans: (c)
218. The dynamic error of an instrument is defined as

a) The difference is full scale reading and actual readings
b) The difference in actual and indicated values
c) The difference in two consecutive readings of the scale
d) None of them
Ans: (b)
219. The multimeter normally employs

a) The so many potentiometers inside it
b) The only one coil with variable number of turns arrangement
c) The multiple series or shunt resistance inside it
d) The completely electronic circuit
Ans: (c)
220. The standard resistors are generally fabricated out of

a) Platinum
b) Copper
c) Meganin
d) Chromium
Ans: (c)
221. The air fraction damping is used for the instruments which have
a) Very high magnetic field

b) Very low magnetic field
c) Zero magnetic field
d) (a) or (b)
Ans: (b)
222. If the instrument scale is cramped for large values, then the scale is calibrated as per
a) Square scale law
b) Uniform scale law
c) Logarithmic scale law
d) None of them
Ans: (c)
223. Generally how many turns in the primary of CT are used?

a) 2
b) 1 to 5
c) 5 to 10
d) 10 to 40
Ans: (b)
224. Which of the method will be used for precision measurement of resistance
a) Voltmeter method
b) Potentiometer method
c) Multimeter method
d) Megger test
e) Bridge method
f) CRO method
Ans: (e)
225. The major application of self-balancing potentiometer is found in

a) Calibration instruments
b) Power systems
c) Electronics
d) Control systems
Ans: (d)
226. The radio frequency can be measured with

a) Resonance frequency meter
b) Weston frequency meter
c) Heterodyne frequency meter
d) Either of the above
Ans: (c)
227. The rectifier instruments do not have the following errors

a) Temperature errors
b) Wave shape errors
c) Frequency error
d) (a), (b) and (c)
Ans: (d)
228. The sensitivity factor of strain gauges is normally of the order of

a) 1 to 1.5
b) 1.5 to 2
c) 0.5 to 1
d) 5 to 10
Ans: (b)
229. CT is used to
a) Step down the current
b) Step up the current
c) Step up the current but step down the voltage
d) Measure very high currents
Ans: (a)
230. Which of the following instrument has poor overload capacity?

a) Moving iron instrument
b) Induction type instruments
c) Electronic instruments
d) Hot wire instruments
Ans: (d)
231. The pulse transformer employs
a) Air core
b) Iron core
c) Ferrite core
Ans: (c)
232. The resolution of potentiometer shall be

a) Zero
b) very small
c) Very large
d) Proportional to its reference voltage
Ans: (c)
233. Which of the following potentiometer is supposed to have infinite resolution?

a) Resistance potentiometer
b) Deposited film potentiometer
c) Kelvins potentiometer
d) None of these
Ans: (b)
234. The LVDT can be used to measure

a) Level
b) Acceleration
c) Speed
d) All of these
Ans: (d)
235. Which of the following recorders are known as null recorders?

a) Strip chart recorders
b) Galvanometric recorders
c) Potentiometric recorders
d) Any of the above
Ans: (c)
236. The Null balance potentiometers are

a) High frequency device
b) Low frequency device
c) Low frequency device with frequency limit of 10 Hz
d) Independent of frequency
Ans: (c)
237. The potentiometric recorders have

a) High sensitivity
b) High sensitivity and independence of lead length
c) Low sensitivity
d) None of these
Ans: (b)
238. The inductance of the current coil of wattmeter is kept

a) As high as possible
b) As low as possible
c) 10 H
d) 1 to 10 H
Ans: (b)
239. The potential coil of wattmeter is designed for

a) Very high inductance
b) Minimum inductance
c) Very low inductance
d) 1 to 10 H
Ans: (b)
240. The potential coil of wattmeter is designed for minimum inductance to

a) Achieve high phase difference between current and voltage
b) Keep current and voltage in same phase
c) Minimize the reactance of the coil
d) Increase the reactance of the coil
Ans: (b)
1. A 2 ohms resistor having 1 ampere current will dissipate the power of
a) 2 Watts
b) 2 Joules
c) 1 Watt
d) 1 Joule
Ans: (a)
2. When 2 volts e.m.f. is applied across a 1 farad capacitor, it will store the energy of
a) 2 Joules
b) 2 Watts
c) 4 Joules
d) 1 Watt
Ans: (a)
3. Thevenin’s equivalent circuit can be used to calculate the power loss in the original circuit.
a) True
b) False
Ans: (a)
4. A 1 H inductance carrying the current of amperes will store the energy of

a) 2 Watts
b) 2 Joules
c) 4 Watts
d) 4 Joules
Ans: (b)
5. An electrical circuit with 10 branches and 7 junctions will have

a) 10 loop equations
b) 4 loop equations
c) 3 loop equations
d) 7 loop equations
Ans: (b)
6. An electrical circuit with 8 independent nodes will have

a) 10 node equations
b) 4 node equations
c) 3 node equations
d) 7 node equations
Ans: (d)
7. If two winding having self-inductances L1 and L2, and a mutual inductance m are
connected in series will opposite, then the total inductance of series combination will be
a) L1 + L2 - 2M
b) L1 + L2 + 2M
c) L1 - L2 + 2M
d) L1 + L2 – M
Ans: (a)
8. The parallel circuit resonance magnifies
a) Current
b) Voltage
c) Power
Ans: (b)
9. The power factor at resonance in R-L-C parallel circuit is

a) 0.5 lagging
b) 0.5 leading
c) Unity
d) Zero
Ans: (c)
10.An inductive circuit resistance 2 ohms and inductance 0.5 H is connected to a 250 volts,
50 Hz supply. What capacitance will be placed in parallel to produce resonance?
a) 700 micro-farad
b) 750 micro-farad
c) 701 micro-farad
d) 714 micro-farad
e) 711 micro-farad
Ans: (d)
11. The current in resonance in parallel L-C circuit will be

a) Very small
b) Very high
c) Zero
d) Infinity
Ans: (a)

a) A galvanometer with low resistance in series is an ammeter
b) A galvanometer with high resistance in series is an ammeter
c) A galvanometer with high resistance in parallel is a voltmeter
d) A galvanometer with low resistance in parallel is a voltmeter
Ans: (a)
13. The time constant of the capacitance circuit defined as the time during which voltage
a) Rises to 63.2% of its final steady value
b) Rises to 38.6% of its final steady value
c) Falls to 36.8% of its final steady value
Ans: (a)
14. Which of the following equation is Poisson’s equation?

a) d2V/dx2 + d2V/dy2 + d2V/dz2 = 0
b) d2V/dx2 = - p/ε0
c) d2V/dx2 + d2V/dy2 = 0
d) d2V/dx2 + d2V/dy2 = p/ε0
Ans: (b)
15. The circuit whose properties are same in either direction is known as
a) Reversible circuit
b) Irreversible circuit
c) Unilateral
d) Bilateral circuit
Ans: (d)
16. A passive network
a) Has no current source

b) Has no e.m.f. source
c) Has neither of the above
d) Has either of the above
Ans: (b)
17.If an electrical network having one or more than one voltage sources is transformed into
equivalent electrical network with a single voltage source (which is open circuit voltage of
previous circuit) with series internal resistance of the network with all voltage sources
replaced by their internal resistances.
The above illustration is called
a) Reciprocity theorem
b) Thevenin’s theorem
c) Superposition theorem
d) Duality
Ans: (b)
18. In the circuit given below, the ammeter reads 0.1 ampere and voltmeter 10 volts. The
internal resistance of the ammeter is 1 ohm and that of voltmeter is 500 ohms. What is the
value of R?
a) 110 ohms
b) 120 ohms
c) 115 ohms
d) 112.5 ohms
e) 125 ohms
Ans: (e)
19.In the circuit given below the power factor will be

a) Lagging
b) Leading
c) Zero
d) Unity,
Ans: (b)
20. If a = 4 < 20° and b = 2 < 10° then the value of a/b, will be :
a) 2 < 10°
b) 2 < 30°
c) 2 < -10°
d) 2 < 20°
Ans: (a)
21. The conjugate of the complex quantity (a + jb) will be

a) – a – jb
b) – a + jb
c) A - jb
d) Ja – b
Ans: (c)
22. Mass in the MKS unit system is analogous to

a) Resistance
b) Voltage
c) Inductance
d) Capacitance
Ans: (d)
23.A damped oscillation has the equation I = 50 e-10tsin 628 t. What will be the frequency of a
oscillation?
a) 50 Hz
b) 75 Hz
c) 100 Hz
d) 60 Hz
Ans: (c)
24. In a loss-free R-L-C circuit the transient current is

a) Sinusoidal
b) Oscillating
c) None-oscillating
d) Square wave
Ans: (a)
25. A 0.5 meter long conductor carrying a current of 2 amperes is placed in a magnetic field
having the flux density of 0.05 wb/m2. What will be the amount of force experienced by the
conductor?
a) 1 New
b) 2 New
c) 0.05 New
d) 0.5 New
Ans: (c)
26. Two parallel conductors carry the same current in the same direction. What kind of
mutual force they will experience?
a) Repulsion
b) Attraction
c) Zero
d) Either (a) or (b)
Ans: (b)

a) The flow of current in the electric circuit involves discontinuous expenditure of energy.
b) The flow of current in the electric circuit requires energy for creating the current but
not to maintain it.
c) In the magnetic circuit energy is needed continuously to maintain the flux.
d) In the magnetic circuit energy is needed for creating the flux initially but not to
maintain it.
Ans: (c)
28. If a coil has a resistance of 10 ohms and an inductance of 1 H, what will be the value of
current 0.1 second after switching on a 500 V d.c. supply?
a) 6.32 A
b) 3.16 A
c) 3.7 A
d) 4.0 A
Ans: (b)
29. The r.m.s. value of an alternating current is given by steady (d.c) current which when
flowing through a given circuit for given time produces
a) The same heat as produced by a.c. when flowing through the same circuit
b) The less heat than produced by a.c. when flowing through the same circuit
c) The more heat than produced by a.c. when flowing through the same circuit
d) 14.4 calories
Ans: (a)
30.In case of an unsymmetrical alternating current the average value must always be taken
over
a) The half cycle
b) The whole cycle
c) Unsymmetrical part of the waveform
d) The quarter cycle
Ans: (b)
31. The average value of the alternating current is more than the r.m.s. value
a) True
b) False
Ans: (b)
32. The amplitude factor of sinusoidal voltage is
a) 1.11
b) 1.57
c) 1.414
d) 0.637
e) 0.707
Ans: (c)
33. An electrical circuit is shown below, what will be the power dissipation in the circuit
assuming P as power across R2 ?
a) 3/4 P
b) 2/3 P
c) 4/3 P
d) 3/2 P
Ans: (c)
34. The resistance of a few meters of wire conductor in closed electrical circuit is
a) Very high
b) Practically zero
c) A few thousand ohm
d) Close to 10,000 ohms
Ans: (b)
35. If two resistances connected in parallel and each dissipates 10 watts the total power
supplied by the voltage source equals
a) 5 watts
b) 10 watts
c) 20 watts
d) 100 watts
Ans: (c)
36. If a parallel circuit is open in the main line, the current

a) Increases in each branch
b) Is zero in all branches
c) Is zero in the highest resistive branch
d) Increases in the branch of the lowest resistance
Ans: (b)
37. In a series parallel circuit, any two resistances in the same current path must be in
a) Parallel with each other
b) Parallel with the voltage source
c) Series with the voltage source
d) Series with each other
Ans: (d)
38. In a series parallel circuit with 6 resistances if there are three in one parallel bank, these
three resistances must have
a) The same current as in the voltage source
b) The same current
c) The same IR drop
d) An IR drop equal to the applied voltage
Ans: (c)
39. In which of the following circuits most current will be produced by the voltage source?
a) 5 volts across a 5 ohm resistance
b) 5 volts across two 5 ohm resistance in series
c) 5 volts across two 5 ohm resistance in parallel
d) 500 volts across a 1 M Ω resistance
Ans: (c)
40. There 60 watt bulbs are in parallel across the 60 volt power line. If one bulbs burns open
a) Rest of the two bulbs will not light
b) All three bulbs will light
c) The other two bulbs will light
d) There will be heavy current in the main line
Ans: (c)
41. If a wire conductor of 0.1 ohm resistance is doubled in length, its resistance becomes
a) 0.1 ohm
b) 0.02 ohm
c) 0.2 ohm
d) 0.05 ohm
Ans: (c)
42. The hot resistance of the bulbs’s filament is higher than its cold resistance because the
temperature coefficient of the filament is
a) Negative
b) Zero
c) Positive
d) About 5 ohms per degree
Ans: (c)
43. The square waveform of current has following relation between r.m.s. value and average
value
a) R.M.S. value of current is greater than the average value
b) R.M.S. value of current is less than the average value
c) R.M.S. value of the current is to average value
d) There is no meaning of r.m.s value and average value for square wave
Ans: (c)
44. There are not transient in resistive circuits.

a) True
b) False
Ans: (a)
45. Transient currents are not driven by any part of the applied voltage to circuit.
a) True
b) False
Ans: (a)
6. The transient currents are associated with the
a) Applied voltage to the circuit

b) Changes in the stored energy in the inductors and capacitors
c) Resistance of the circuit
d) Impedance of the circuit
Ans: (b)
47. The double energy transients occur in the

a) R-L circuit
b) R-C circuit
c) Pure inductive circuit
d) R-L-C circuit
Ans: (d)
48. A closed switch has a resistance of

a) Infinity
b) Zero
c) About 500 ohms
d) About 50 ohms at room temperature
Ans: (b)
49. The ionization current in the liquids and gases results from
a) Protons
b) Electrons
c) Neutrons
d) Positive or negative or negative ions
Ans: (d)
50. Two 500 ohms, 1 watt resistors are connected in parallel. Their combined resistance and
wattage rating will be
a) 5000 ohms, 1 watt
b) 250 ohms, 2 watts
c) 1000 ohms, 2 watts
d) 500 ohms, 2 watts
Ans: (b)
51. A resistor is connected across a 45 volt battery to provides 13 mA of current. The

required resistance with suitable wattage rating will be
a) 4.5 ohms, 1 watt
b) 45 ohms, 10 watts
c) 1000 ohms, 2 watts
d) 45,000 ohms, 1/3 watt
Ans: (d)
52. A 2.2 lead acid cell

a) Is a primary cell
b) Is a secondary cell
c) Has unlimited shelf life
d) Has a maximum current rating of about 150 mA
Ans: (b)
53. The formation of the hydrogen bubbles around the carbon electrode in a dry cell is
a) Local action caused by chemical impurities
b) Polarization caused by electrolysis
c) Depolarization caused by manganese dioxide
d) An advantage because it increases the voltage output
Ans: (b)
54. When a lead acid battery is charged

a) The battery voltage must be more than charging voltage
b) Connect the positive battery terminal to the negative on the charging current
c) The charging current must flow in same direction as the discharging current
d) Connect negative to negative and positive to positive
Ans: (d)
55. The Edison cell

a) Is a primary cell
b) Uses sulphuric acid electrolyte
c) Has 2.5 volts output
d) Has nickel and iron electrolyte
Ans: (d)
56. The cells are connected in series to

a) Increase the current output
b) Increase the voltage output
c) Decrease the internal resistance
d) Decrease the amount of charging voltage required
Ans: (b)
57. A 45-volt source with an internal resistance of 2 ohms is connected across a wire-wound
resistor. The maximum power will be dissipated in the resistor when its resistance equals
a) Zero
b) Ohms
c) 45 ohms
d) Infinity
Ans: (b)
58. A magnet can pick up nail because of

a) Excess charge on the nail
b) Magnetic induction
c) Declination of magnetic field
d) Molecular magnets in the air around the nail
Ans: (b)
59. A magnetic compass point to the

a) Geographical poles
b) True north pole
c) Magnetic north pole
d) Agonic line of the earth filed
Ans: (c)
60. If the wire which is vertical to this page has electron flow downward the conductor will
have
a) No magnetic field
b) A counter-clockwise field in the plane of the power
c) A clockwise field in the plane of the paper
d) A counter-clockwise field in the plane perpendicular to the paper
Ans: (b)
61. Which lines of forces produced by two magnetic fields, the field
a) Is stronger where the lines of force are in the same direction

b) Is stronger where the lines are in opposite direction
c) Has the same strength as for one magnet
d) Is weakest where the lines are in the same direction
Ans: (a)
62. A solenoid is a coil which

a) Acts as bar magnet only when there is no current in the conductor
b) Acts as bar magnet only when the current flows in the coil
c) Is similar to ring magnet because there is no air gap
d) Acts as bar magnet only when it has iron core
Ans: (b)
63. The force tending to make a loop of wire rotate is called

a) Energy
b) Power
c) Voltage
d) Torque
Ans: (d)
64. Motor action in a wire conducting current can be produced

a) Without any additional magnetic field
b) Move the conductor from weaker field toward stronger field
c) Move the conductor from stronger field toward a weaker field
d) Produce the motion of the conductor but not rotation
Ans: (c)
65. The r.m.s. value of an a.c. signal is 10 volts. The peak to peak value will be
a) 6.37 volts
b) 10 volts
c) 14 volts
d) 28 volts
Ans: (c)
66. When two waves are 90° out of phase

a) Each has its peak value at the same time
b) Each has its minimum value at the same time
c) One has its peak value when the other has zero value
d) One has its positive peak when the other has its negative peak
Ans: (c)
67. Which of the following can produce maximum induced voltage?

a) 1-amp. D.c. current
b) 50-amp. D.c. current
c) 1-amp. 60 cycles a.c. current
d) 1-amp. 490 cycles a.c. current
Ans: (d)
68. When the alternating voltage reverses in polarity, the current its produces
a) Reverses its direction
b) Has the same direction
c) Has phase angle of 180 degree
d) Alternates at 1.4 time the frequency of the applied voltage
Ans: (a)
69. An alternating current can induce voltage because it has

a) High r.m.s. value
b) Varying magnetic field
c) Stronger field than direct current
d) Constant magnetic field
Ans: (b)
70. If the length, number of turns, and area of a coil are doubled, the inductance of the coil is
a) The same
b) Double
c) Quadrupled
d) One-quarter
Ans: (c)
71. The d.c. resistance of a coil made with 100ft of gauge No. 30 copper wire is
approximately
a) Less than one ohm
b) 10.5 ohms
c) 104 ohms
d) More than 1 M Ω
Ans: (b)
72. An open coil has

a) Zero resistance and high inductance
b) Infinite resistance and zero inductance
c) Infinity resistance and normal inductance
d) Zero resistance and inductance
Ans: (b)
73. Inductive resistance is measured in ohms because it

a) Reduces the amplitude of alternating current
b) Increases the amplitude of alternating current
c) Increases the amplitude of direct current
d) Has a back e.m.f. opposing the voltage output of a battery
Ans: (a)
74.Inductive reactance applied to sine wave only because it

a) Increases with lower frequency
b) Increases with lower inductance
c) Depends on the factor 2π
d) Decreases with the higher frequencies
Ans: (c)
75. In a sine wave a.c. circuit with 90 ohms R in series with 90 ohms XL, phase angle θ
equals
a) 0°
b) 60°
c) 45°
d) 90°
Ans: (c)
76. An arc across the switch opening an R-L circuit is a result is a result of the
a) Long time constant

b) Large self-induced voltage across the inductance
c) Source of the voltage caused by IR drop across the resistance
d) Low resistance of the open switch
Ans: (b)
77. In a sine wave a.c. circuit with a resistive branch and inductive branch in parallel, the
a) Voltage across the inductor leads the voltage across the reactance by 90°
b) Resistance branch current is 90° out of phase with the inductive branch current
c) Resistive and inductive branch current are 180° out of phase
d) Inductive and resistive branch currents are in phase
Ans: (b)
78. A.d.c. voltage of 12 volts applied across an inductance in series with a switch
a) Can produce the induced voltage as the current decreases when the switch is opened
b) Cannot produce the induced voltage as the voltage applied has the one polarity
c) Produces more induced voltage when the switch is closed than the switch is opened
Ans: (a)
79. Alternating current in the inductance will produce maximum induced voltage when the
current has its
a) Maximum value
b) Maximum change in magnetic field
c) Minimum change in magnetic field
d) 0.707 × Peak
Ans: (b)
80. Two 300-mh chokes connected in series will have the total inductance of
a) 60 mh
b) 300 mh
c) 150 mh
d) 600 mh
Ans: (d)

a) Iron core has maximum eddy-current losses
b) Laminated iron core has minimum eddy-current losses
c) Power-iron core has the maximum eddy-current losses
d) Air core has the minimum eddy-current
Ans: (d)
82. Two waves have the frequency of 500 Hz and one is set at its maximum value whereas
the other at zero, the phase angle between them will be
a) 0°
b) 180°
c) 360°
d) 90°
Ans: (d)

a) Ceramic capacitors must be connected in the correct polarity
b) Electrolytic capacitor must be connected in the correct polarity
c) Mica capacitors are available in capacitance value of 1 to 10 micro-farad
d) Air capacitors have a blackband to indicate the outside foil
Ans: (b)
84. Voltage applied across a ceramic dielectric produces an electrolytic field 100 times
greater than air. What will be the value of dielectric constant?
a) 33.333
b) 50
c) 1000
d) 100
Ans: (d)
85. If an a.c. voltage is applied to capacitive circuit, the alternating current can flow in the
circuit because
a) Of high peak value
b) Charging current can flow
c) Discharge current can flow
d) Varying voltage produces the charging and discharging currents
Ans: (d)
86. The amount of capacitive reactance with higher frequencies

a) Decreases
b) Increases
c) Remains same for frequencies
d) Decreases as the voltage increases
Ans: (a)
87. A steady d.c. voltage is applied to capacitor, after changes to battery voltage, the current
in the circuit
a) Depends on the current rating of the battery
b) Is greater for larger values of capacitances
c) Is smaller for larger values of capacitances
d) Is zero for any value of capacitance
Ans: (d)
88. In sine wave a.c. circuit with Xc and R in series, the

a) Voltages across R and Xc are in phase
b) Voltages across R and Xc are 180° out of phase
c) Voltages across R leads the voltages across X c by 90°
d) Voltage across R lags the voltage across X c by 90°
Ans: (c)
89. A capacitor can store the change because it has dielectric between two conductors.
a) True
b) False
Ans: (a)
90. The thinner the dielectric the more the capacitance and lower is the voltage breakdown
rating for a capacitor
a) True
b) False
Ans: (a)
91. In parallel L-C circuit, at the resonant frequency
a) A line current is maximum

b) The total impedance is maximum
c) The total impedance is maximum
d) The inductive branch current is maximum
Ans: (c)
92. The series and parallel resonance in L-C circuit differs in that
a) Series resonance needs a high-resistance source for sharp rise in current
b) Series resonance needs a low-resistance source for sharp rise in current
c) Parallel resonance needs a low-resistance source for a sharp increase in impedance
d) Parallel resonance needs a low-resistance source for a sharp rise in line current
Ans: (b)
93. In a series L-C circuit at the resonant frequency the
a) Current is minimum
b) Voltage across C is minimum
c) Impedance is maximum
d) Current is maximum
Ans: (d)
94. A ferrite core has less eddy-current loss than an iron core because ferrites have
a) Low resistance
b) High resistance
c) Low permeability
d) High hysteresis
Ans: (b)
95. A coil with large distributed capacitance has a

a) High resonant frequency
b) Low resonant frequency
c) High Q
d) Low a.c. resistance
Ans: ()
96. A capacitor with power factor of 0.002 has a Q of

a) 0.002
b) 20
c) 200
d) 500
Ans: ()
97. A permalloy enclosure is the best shield against a

a) Static change
b) Steady magnetic field
c) Varying magnetic field
d) Stray capacitance
Ans: ()
98. With stray capacitance of 10μF, the capacitive reactance at 160 MHz equals
a) 10 ohms
b) 160 ohms
c) 100 ohms
d) 1000 ohms
Ans: (c)
99. The intrinsic impedance of free space is

a) 500 ohms
b) 750 ohms
c) 637 ohms
d) 377 ohms
Ans: (d)
100.The dissipation factor of a good dielectric is of the order of

a) 0.02
b) 0.002
c) 0.2
d) 0.0002
Ans: (d)
101. The dissipation factor of a good dielectric is practically same as power factor of the
dielectric.
a) True
b) False
Ans: (a)
102. The velocity of propagation of an electromagnetic wave is given by

a) √LC
b) √(L/C)
c) √(1/LC)
d) 1/√LC
Ans: (d)
103. The total electric flux through any closed surface surrounding charges is equal to the
amount of charge enclosed. The above illustration is known as
a) Maxwell’s First Law
b) Maxwell’s Second Law
c) Gauss’s Law
d) Coulomb’s Square Law
Ans: (c)
104. The magnetic flux density B is analogous to

a) Electromotive force V
b) Displacement current D
c) Electric intensity
d) Electric displacement
Ans: (c)
105. Which of the following is the continuity equation ?

a) ∂p/∂t = div i
b) curl H = 𝒊
c) div D = P
d) div i = 0
Ans: (a)
106. The relative permeability of paramagnetic substance is
a) Unity
b) Slightly more than unity
c) Zero
d) Less than unity
Ans: (b)
107. The relative permeability of ferromagnetic material may have a value of several hundred
or even several thousand
a) True
b) False
Ans: (a)
108. If A is the vector which of the following statements is true?

a) Div curl A = A
b) Div curl A = curl A
c) Div curl A = 0
d) Div curl A = curl div A
Ans: (c)

a) The magnetomotive force around a closed path is equal to the conduction current plus
electric displacement through any surface bounded by the path
b) The electromotive force around a closed path is equal to the time derivative of the
electric displacement through any surface bounded by the path
c) The total electric displacement through the surface enclosing a volume is not equal to
total charge within the volume
d) The net magnetic flux emerging through any closed surface is zero
Ans: (d)
110.Voltage across the resistance in R-L-C series circuit at resonance frequency is

a) Much higher than applied voltage
b) Much less than applied voltage
c) Function of value of inductance
d) Function of L/C ratio
e) Equal to applied voltage
Ans: (e)
111. A horseshoe magnet is head vertical with its ends resting on a horizontal board. The
plane passing through its poles (assumed to lie at its ends) is in magnetic meridian. If N-pole
of the magnet is towards magnetic south of the earth, the neutral point will lie
a) Within the poles of shoe magnet
b) At points along the axial line of the magnet
c) At point along the equatorial line of the magnet
d) At points not lying exactly on the horizontal board
Ans: (c)
112. A horseshoe magnet is far removed from magnetic substance. The magnetic potential
will be zero at a point
a) Lying on its axial line
b) Lying on the centre of the line joining the two poles
c) Lying anywhere on its equatorial line
d) On the centre of the magnet
Ans: (c)
113. Three capacitors each of the capacity C are given. The resultant capacity 2C/3 can be
obtained by using them
a) All in parallel
b) All in series
c) Two in series and third in parallel across this combination
d) Two in parallel and third in series with this combination
Ans: (d)
114. Two spheres of radii 10 and 20 cm have charges 100 and 200 e.s.u respectively. These
are joined by a fine wire. The loss of energy will be
a) 1/2 × (10 × 20)/(10 +10) (200 + 100)2 ergs
b) 1/2 × (10+20)/(10×20) (200 – 100 ) ergs
c) 1/2 × (200 - 100)2 ergs
d) Zero
Ans: (d)
115. What will be the frequency of the following wave

a) 10 KHz
b) 5 KHz
c) 100 KHz
d) 150 KHz
Ans: (c)
116.If the pulse repetition of a square wave is 60 microseconds, the pulse repetition rate will
be
a) 5 KHz
b) 16 KHz
c) 10 KHz
d) 15 MHz
e) 15 Hz
Ans: (b)
117. Using the following figure, find the capacitor discharge voltage when the switch is first
placed in position A for 4.7 × 10-3 seconds, and then when the switch is placed in position B
for 4.7 × 10-3 seconds. Assume that the initial charge on the capacitor is zero.
a) 9.45 volts
b) 15 volts
c) 3.5 volts
d) 6 volts
Ans: (c)
118. The Ohm’s law states that

a) V is proportional to I
b) I is proportional to V
c) V is proportional to IR
d) V is proportional to R
Ans: (a)
119. The electromagnetic radiation can only be emitted or absorbed by a matter in small
discrete unity is called
a) Proton
b) Electron
c) Photon
d) Neutron
Ans: (c)
120. If the peak voltage of a wave is 15 V and pulse repetition time is 60 microseconds, with
will be the average value of voltage?
a) 10 volts
b) 5 volts approximately
c) 15 volts
d) 7 volts
Ans: (b)
21. A 100 watt, 250 V bulb will have more resistance than 60 watt, 250 V bulb.
a) True
b) False
Ans: (b)
122. The Kirchhoff᾽s laws fail in

a) Lumped parameters circuit
b) Distributed parameters circuit
c) Nonlinear circuits
d) Linear circuit
e) Bilateral circuit
Ans: (b)
123. When a circuit of 0.1 A is passed through a coil of 2000 turns, the MMF produced by
the coil will be
a) 100 AT
b) 200 AT
c) 300 AT
d) 10 AT
Ans: (b)

a) The magnetic flux inside and exciting coil is greater than its outside surface.
b) The magnetic flux inside and exciting coil is same as on its outside surface.
c) The magnetic flux inside an exciting coil is lower than its outside surface.
d) The magnetic flux inside an exciting coil is zero
Ans: (b)
125. All the lines of magnetic flux on a coil produced by a uniform magnetic field are parallel
and equidistance.
a) True
b) False
Ans: (a)
126. The magneto-motive force is

a) The flow of an electric current
b) The sum of all the current embraced by one line of magnetic field
c) The passage of magnetic field through an exciting coil
d) The voltage across the two ends of exciting coil
Ans: (b)
127. The “Ampere-Turns” are

a) The product of the number of the turns and current of the coil
b) The number of the turns of a coil through which current is flowing
c) The currents of all turns of the coil
d) The turns of transformer winding
Ans: (a)
128. The uniform magnetic field is

a) The field a single conductor
b) The field of set of parallel conductors
c) Field in which all line of magnetic flux are parallel and equidistant
Ans: (c)
129. The reluctance of magnetic circuit depends on the length of magnetic flux path, cross-
sectional area presented to the magnetic field and magnetic properties of material in which
the magnetic field is generated
a) True
b) False
Ans: (a)
130. The change of cross-sectional area of conductor in magnetic field will affect
a) Resistance of conductor
b) Reluctance of conductor
c) (a) and (b) both in the same way
Ans: (c)
131. The ferromagnetic materials have a relative permeability μr

a) Equal to one
b) Less than one
c) Far greater than one
d) Zero
Ans: (c)
132.The magnetic field can penetrate empty space.

a) True
b) False
Ans: (a)
133. What will be the current passing through the ring shaped air cored coil when number of
turns is 900 and ampere-turns are 2700?
a) 3
b) 1.5
c) 6
d) 9
Ans: (a)
134. What will be the magnetic potential difference across the air gap of 4 cm length in the
magnetic field of 400 AT/ m?
a) 4 AT
b) 8 AT
c) 16 AT
d) 20 AT
Ans: (c)
135. A certain amount of current flows through a ring-shaped coil with fixed number of turns.
How does the magnetic induction B varies inside the coil if an iron core is threaded into coil
without dimensional change of coil?
a) Increases
b) Decreases
c) Remains same
d) First increases and then decreases depending on the depth of iron core insertion
Ans: (a)
136. The initial permeability of an iron rod is
a) The permeability at the end of an iron rod

b) The permeability almost in non-magnetised state
c) The lowest permeability of iron rod
d) The highest permeability of iron rod
Ans: (b)
137. The magnetic reluctance of a material

a) Increases with increasing cross-sectional area of material
b) Decreases with increasing cross-sectional area of material
c) Does not vary with increasing cross-sectional area of material
d) Does vary from small increase in cross-sectional area of the material
Ans: (b)
138. The magnetic field strength H and magnetic induction B are independent of each other.
a) True
b) False
Ans: (b)
139. Which part of the magnetic path requires largest MMF?

a) Core
b) Air gap
c) Coil
d) Inductance
Ans: (b)
140. The presence of magnetic field can be determined by

a) Detecting the lines of magnetic flux
b) Deflection of a magnetic compass needle
c) Heating the surrounding air
d) Touching the magnetically affected area
Ans: (b)
141. How does the magnetic compass needle behave in a magnetic field?
a) It starts rotating
b) It assures a position right angle to magnetic field
c) It assures a position which follows a line of magnetic flux
Ans: (c)
142. The magnetic reactance has the same unit as electric reactance.
a) True
b) False
Ans: (b)
143. MMF is analogous to

a) Electric current in electrical circuit
b) Electromotive force
c) Current density in conductor
d) Voltage
Ans: (b)

a) The strength of magnetic flux in a simple magnetic field continuously increases from
initial value of final value.
b) The strength of magnetic flux in a simple magnetic field continuously decreases from
initial value to final value.
c) The strength of magnetic flux in simple magnetic field is constant and has same value
in every part of the magnetic field.
d) None of the above statements is correct.
Ans: (c)
145. There is no existence of such material which is completely impermeable to magnetic

flux.
a) True
b) False
Ans: (a)
146. The stray line of magnetic flux is defined as

a) A line of magnetic flux in a non-uniform field
b) A line of magnetic flux which does not follow the designed path
c) The mean length of a right shaped coil
d) A line vertical to the flux lines
Ans: (b)
147. In the given circuit, the voltage V is reduced to half. The current I will change to
a) 2I
b) I/2
c) I/[ √R2 + (XL- XC )]
d) I/[√(XL- XC )2 )]
Ans: (b)
148. The current in the loaded battery flows from

a) + ve to – ve plate
b) – ve to + ve plate
c) Between plates
d) Between terminals
Ans: (b)
149. In the circuit shown, the current in the resistance 1 shall be

a) 3/7I
b) 3/4I
c) I
d) 7/3I
e) 1/4I
Ans: (a)
150. The four bulbs of 40 watts each are connected in series with a battery across them,
which of the following statements is true?
a) The voltage across each bulb is same
b) The power dissipation in each bulb is not same
c) The current through each bulb is same
Ans: (c)
151. In the given circuit, the Kirchhoff’s current law at the point A is applied. Which of the
following relation is correct
a) I1 = I2- I3
b) I1 - I3+ I3=0
c) I1- (I2+ I3 )=0
d) I1= -(I2+ I3 )
Ans: (c)
152. The voltage source of 220 V shown in the figure will deliver the total current to the
circuit of
a) 4 A
b) 2 A
c) 50 A
d) 100 A
Ans: (c)
153. An inductance coil of 10 H develops the counter voltage of 50 volts. What should be the
rate change of current in the coil ?
a) 5 A/sec
b) 10 A/sec
c) 1 A/sec
d) 100 A/sec
Ans: (a)
154. An peak value of the sinusoidal voltage is 10 volts. What will be the effective of
voltage ?
a) 14.14 volts
b) 1.414 volts
c) 0.707 volts
d) 7.07 volts
Ans: (d)
155. If the effective voltage of the sinusoidal voltage is 11 volts. What will be the average
value of sinusoidal voltage ?
a) 5 volts
b) 10 volts
c) 1.1 volts
d) 11 volts
e) 121 volts
Ans: (b)
156. If a conductor is put in a magnetic field, at what angle the conductor should cut the
magnetic field to induce maximum current in it ?
a) 10°
b) 20°
c) 90°
d) 120°
e) 180°
f) -90°
Ans: (c)
157. For which of the following parameter variation, the capacitance of the capacitor remains
unaffected ?
a) Nature of dielectric
b) Thickness of the plates
c) Distance between the plates
d) Area of the plates
Ans: (b)
158. If two capacitors with 20 μF capacitance each are connected in series. What will be the
net capacitance of the circuit ?
a) 10 μF
b) 20 μF
c) 40 μF
d) 80 μF
Ans: (a)
159.In the above question, if the capacitors are connected in parallel, what will be the net
capacitance ?
a) 40 μF
b) 20 μF
c) 10 μF
d) 30 μF
Ans: (a)
160. The three vector diagrams are shown below. While of the diagram is for pure resistance
circuit.
161. In the vector diagrams shown in Q.160, diagram (a) corresponds to

a) Pure inductive circuit
b) Pure resistive circuit
c) Pure resistive circuit
Ans: (b)
162. In the vector diagrams shown in Q. 160 the diagram (b) corresponds to
a) Pure inductive circuit
b) Pure resistive circuit
c) Pure capacitive circuit
Ans: (a)
163. Which of the following expression is true for apparent power in an AC circuit ?
a) Vr.m.s.×Ir.m.s.
b) Vmean×Imean
c) Vpeak×Ipeak
d) V I cos⁡ϕ
Ans: (a)
164. The sum of the rms potentials in the RC circuit does not follow the Kirchhoff’s law.
a) True
b) False
Ans: (a)
165. The power dissipation in the pure capacitance of RC circuit will be

a) Zero
b) Small
c) Higher than dissipation in resistance
d) Equal to dissipation in resistance
Ans: (a)
166. Which of the following expression is correct for series reactance X cs if three
capacitors C1, C2 and C3 are connected in series?
a) 1/Xcs = 1/Xc1 + 1/Xc2 + 1/Xc3

b) Xcs = Xc1 + Xc2 + Xc3
c) Xcs = 1/Xc1 + 1/Xc2 + 1/Xc3
d) Xcs = 1/Xc1 + Xc2+ Xc3
Ans: (b)
167. An RC network is shown blow, can be used as high pass and low pass filter as well. For
which of the condition lower cut-off frequency occurs as high pass filter ?
a) ES = ER
b) ES+ EC
c) ER=0.707 EC
d) ER= 0.707 ES
Ans: (d)
168. Which of the following relationship shown by curves is true for inductive circuit ?
169. The Laplace transform of the unit function is given by

a) 1/s
b) 1/s2
c) S
d) 1
Ans: (a)
170. The Laplace transform of the function ƒ(t) = E-at is given by

a) 1/a2+ s2
b) 1/a+s
c) 1/a+s
d) s2/a2+ s2
Ans: (b)
171. The Laplace transform of the function ƒ(t) = cos⁡βt is given by

a) β/s2+β2
b) s/s2+β2
c) 1/2+β2
d) β/s+β
Ans: (b)
172. The Laplace transform of the function ƒ(t) = sin⁡βt is given by

a) β/s+β2
b) β/s2+β2
c) s/s2+β2
d) β2/s+β
Ans: (a)
173. Whish of the following is the Laplace transform of ƒ(t) = t ?

a) 1/s
b) 1/s2
c) 1/s3
d) S
Ans: (a)
174. The expression £ (t) = n1/sn+1 is true the function
a) ƒ(t) = tn
b) ƒ(t) = ntn
c) ƒ(t) = t/n
d) ƒ(t) = tn
Ans: (a)
175. Which of the following conditions are necessary for validity of “Initial Value Theorem”
Line s F(s) = line ƒ(t)
s →∞ t → 0
a) ƒ(t) and its derivative ƒ(t) must have Laplace transformer

b) if the Laplace transform of ƒ(t) is F(s), the lim sF(s) must exist
c) only ƒ(t) must have Laplace transformer
d) (a) and (b) both
Ans: (d)
176. The Laplace transform of a unit impulse at t = 0 is

a) S
b) 1/s
c) Unity
d) 1/s2
Ans: (c)
177.If the Laplace transform of unit step is 1/s. How many poles will be located at the origin
of the s-plane?
a) One
b) Two
c) Three
d) None
Ans: (a)
178. If the Laplace transform of the function ƒ(t) = e-at is 1/(s+α) then Which of the following
statement will be true?
a) One pole will be located on the real axis of s-plane at – α
b) One pole will be located on the imaginary axis of s-plane at ± ϳω
c) One complex pole will be located at the origin of s-plane
d) One complex pole will be located in s-plane at – α ± јω
Ans: (a)
179. For which of the following function the Laplace will be 2/s2
a) ƒ(t) = t
b) ƒ(t) = 1
c) ƒ(t) = δt
d) ƒ(t) = 2t
e) ƒ(t) = t2
Ans: (e)
180. Which of the following operations is to be carried on to get ramp function from unit
impulse at t = 0 ?
a) integrate unit impulse function once
b) integrate unit impulse function twice
c) integrate unit impulse function thrice
d) differentiate unit impulse function twice
e) differentiate unit impulse once as a function of time
Ans: (c)
181. Which of the following function represents parabolic characteristics?
a) ƒ(t) = t
b) ƒ(t) = t2
c) ƒ(t) = e-at
d) ƒ(t) = Ut
Ans: (b)
182.The power factor of a purely resistive circuit will be

a) unity
b) zero
c) infinity
d) 0.5
Ans: (a)
183. The quality factor of RCL circuit will increase if the

a) R decreases
b) R increases
c) Voltage increases
d) Impedance increases
Ans: (a)
184.If the diameter of a current carrying conductor is doubled, the resistance will
a) Be reduced to half
b) To reduced to one-fourth
c) Remain same
d) Be doubled
Ans: (b)
185. The inductance across the points AB in the circuit shown is given by
a) 1
b) 2
c) 3
d) 5
e) 4
Ans: (d)
186. A pure inductance is connected with DC source as shown. The inductance will behave
as
a) Open circuit
b) Closed circuit
c) Short circuit
Ans: (c)
187. A voltage divider and its Thevenin’s equivalent circuit is shown below. What will be the
value of voltage source V and resistance R.
a) 10 V, 80 Ω
b) 10 V, 120 Ω
c) 4 V, 48 Ω
d) 5 V, 50 Ω
Ans: (c)
188. In the circuit shown below, what will be the voltage uR at t = 0?
a) 0
b) V
c) V/2
d) 0.37 V
e) 0.63 V
Ans: (b)
189. In the figure of Q. 188, what will be the voltage uR at t = ∞?

a) 0
b) V
c) 0.37 V
d) 0.63 V
c) V/√3
Ans: (a)
190. In the figure of Q. 188, what will be the voltage uC at t = 0?

a) 0
b) V
c) 0.37 V
d) 0.63 V
Ans: (a)
191. In the figure of Q. 188, what will be the voltage uC at t = ∞?

a) V
b) 0
c) V/√3
d) 0.63 V
Ans: (a)
192. A pulse of width T seconds is applied to an RC circuit. The response of the circuit is
shown below. Which kind of filter circuit will produce this response?
a) Low pass filter
b) High pass filter
c) Medium pass filter
Ans: (a)
193. If the output signal of a circuit appropriate the time integral of the input signal, such
circuit is called
a) Differentiator
b) Integrator
c) Multiplier
d) Divider
Ans: (b)
194. A pulse of T seconds width is applied to an RC circuit-produces the following response.

What kind of filter will generate such response?
a) Low pass filter
b) High pass filter
c) Medium pass filter
Ans: (b)
195. A pulse of T seconds width is applied to an RC circuit. What kind of circuit will be
required to produce a ramp response ?
a) Low pass filter with low time constant
b) Low pass filter with high time constant
c) An integrator
d) A differentiator
e) (b) or (c)
Ans: (e)
196. Two resistances R1 and R2 are connected in series across the voltage source where
R1 > R2. The largest voltage drop will be across
a) R1
b) R2
c) either R1 orR2
d) none of them
Ans: (a)

a) A Norton equivalent is series circuit
b) A Thevenin equivalent is a parallel circuit
c) Resistive circuit is a dual pair
d) R-L circuit is a dual pair
e) L-C circuit is a dual pair
Ans: (c)
198. The time constant of a series RC circuit is given by

a) RC
b) R/C
c) R2C
d) RC2
Ans: (a)
199.If resistance is 10Ω and inductance is 1 H in an RL series circuit. What will be the time
constant of this series RL circuit?
a) 10 second
b) 0.1 second
c) 100 second
d) 0.001 second
Ans: (b)
200. The magnitude of the impedance 20-15j is given by

a) 5 Ω
b) 15 Ω
c) 25 Ω
d) 625 Ω
Ans: (c)
201. If an inductive coil has 50 Ω resistance and 500 Ω inductive reactance. What will be the
quality of factor Q?
a) 5
b) 50
c) 100
d) 10
Ans: (d)
202. The impedance Z1 = 4 + 3j and Z2 = 4 – 3j are added. What will be resultant impedance
Z1 + Z2 ?
a) 5 <15°
b) 8 <0°
c) 8 <180°
Ans: (b)
203. The phasors for which of the following pair are 180° out of phase for VL, VC and VR ?
a) VL and VR
b) VC and VR
c) VC and VL
Ans: (c)
204. If impedance Z1 = 10 <10° and Z2 = 10 <15°, what will be the value of Z1 × Z2 ?
a) 100 <15°
b) 10 <5°
c) 100 <50°
d) 20 <15°
Ans: (a)
205. In the Q. 204, what will be the value of Z1/Z2 ?

a) 1 <5°
b) 10 <2°
c) 1 <20°
d) 100 <2°
Ans: (a)
206. The Fourier series expansion of an odd periodic function contains

a) Cosine terms
b) Constant terms only
c) Sine terms
d) Cosec terms only
Ans: (c)
207.The Fourier series expansion of an even periodic function contains

a) Sine terms
b) Constant terms
c) Cosine terms
d) Harmonics
Ans: (c)
208. Which of the following conditions is true for even function?

a) ƒ(t) = - ƒ(n + T/2)
b) ƒ(t) = - ƒ(t)
c) ƒ(t) = ƒ(-t)
d) ƒ(t) = ƒ(t)
Ans: (c)
209. What will be the equivalent conductance G of the circuit shown below. G1, G2 and G3 are
the conductance of individual circuit branch
a) G = G1 + G2 + G3
b) 1/G = G1 + G2 + G3
c) 1/G = 1/G1 + 1/G2 + 1/G3
d) G = 1/G1+G2+G3
Ans: (a)
210. If the electrical current is compared to the flow of water through a pipe, which part of
the pipe system is analogous to conductance ?
a) Cross-section of the pipe
b) Length of the pipe
c) Pipe gradient
d) Pipe material
Ans: (a)
211. The electrical circuit A and B are shown below. Which of the battery of the flowing
circuit will be loaded more and by what amount of current provided resistance of bulbs
are same?
a) A, IA = 4IB
b) B, IA = IB
c) A, IB = 4IA
d) B, IA = 2IB
Ans: (a)
212.If one cycle of a.c. waveform occurs every second, what will be the frequency of this
waveform?
a) 0.2 Hz
b) 0.5 Hz
c) 1 Hz
d) 2 Hz
Ans: (c)
213. A circuit is shown below. What will be the steady state value of the current?
a) 1 amp
b) 2 amps
c) 4 amps
d) 5 amps
Ans: (c)
214. There are two circuits shown below. Which of the following statement is true?
a) The lamp will be brightest when contact K moves to A in circuit (a)
b) The lamp will be brightest when the contact K moves to B in circuit (a)
c) The lamp will be brightest when contact K is moved to A the circuit (b)
d) Circuit (a) is a potential divider
Ans: (b)
215.In Q. 214, circuit (a) behaves as

a) Current limiting source
b) Potential divider
c) Light limiting source
Ans: (a)
216. In the Q. 214, the circuit (b) behaves as

a) Current limiting source
c) Light limiting source
Ans: (b)
217. Wheatstone bridge is used to measure

a) Current
b) Voltage
c) Resistance
d) Power
Ans: (c)
218. What will be the energy used by the battery if the battery has to drive 625 ×
1016 electrons with potential difference of 10 V across the terminals?
a) 5 joules
b) 10 joules
c) 6.25 joules
d) 1.6 joules
Ans: (b)
219. If a night bulb is used at less brightness than rated one, which of the following method
one will choose to achieve required brightness?
a) Current-limiting resistor
c) Source Voltage Reduction
d) Either (a) or (b)
Ans: (d)
220. A sine wave of 220 V, 50 Hz AC will achieve its negative maximum value in
a) 10 m sec
b) 15 m sec
c) 20 m sec
d) 50 m sec
Ans: (b)
221. If a neon bulb of 60 watts is connected 220 V, Ac source and draws 272 mA current,
what be the resistance of the bulb filament?
a) 1000 Ω
b) 808 Ω
c) 800 Ω
d) 60 Ω
e) 272 Ω
Ans: (c)
222.An inductive circuit is shown below, which of the equation represents the circuit
correctly?
a) V = Ldi/dt
b) V = IR + Ldi/dt
c) V = IR
d) V = IR + 1/L di/dt
Ans: (d)
223. Which of the following condition is true for maximum transfer of power if the internal
impedance of voltage source is Zs = R + jx
a) ZL = Zs
b) ZL = R – jx
c) ZL = R + jx
d) ZL = Zs/2
Ans: (b)
224. In the Q.223, what will be the maximum transfer of power to ZL ?
a) V2/R
b) V2/2R
c) V2/R2
d) V2/4R
Ans: (b)
225. An RC circuit is shown below, the current will reach its maximum value
a) After 1000 μ sec of turning on the switch
b) After 500 μ sec of turning on the switch
c) After 50 μ sec of turning on the switch
d) Immediately after turning on the switch
Ans: (d)
226. The maximum current in the circuit of Q. 225 will be
a) 1 A
b) 100 A
c) 2 A
d) 5 A
Ans: (a)
227.If D is the electric displacement density and E is the electric field strength, then D and E
can be related by
a) D = E2/ε
b) D = E/ε
c) D = εE2
d) D = εE
Ans: (d)
228. If μr is the relative permeability of a given medium, μ is a permeability and μ0 is the
permeability of the free space, then the expression for μr is given by
a) μr = μ0/μ
b) μr = μ/μ0
c) μr = μ0/μ2
d) μr = μ0/μ
Ans: (d)

a) The current in a discharging capacitor grows exponentially
b) The current in a discharging capacitor decays exponentially
c) The current in the discharging capacitor grows linearly
d) The current in the discharging capacitor decreases constantly
Ans: (a)
230. Which of the following indicates the units of displacement density?

a) Ampere-meter
b) Coulomb-meter
c) Coulomb/m2
d) Volt m2
Ans: (c)
231.If RC is the time constant of the R-C circuit, now much time the capacitor will take to get
fully charged?
a) RC seconds
b) 4 RC seconds
c) 3 RC seconds
d) 5 RC seconds
Ans: (c)
232. Find the change in potential energy of a system where change Q0 is carried to the charge
Q1 at a distance of 10 meters with a 10 N force?
a) 10 N/meter
b) 100 N-meter
c) 10 joules
d) 50 N/meter
Ans: (b)
233. Which of the following phenomenon takes place when an electromagnetic wave
propagates through free space?
a) Reflection
b) Phase shift
c) Attenuation
d) Distortion
Ans: (c)
234. Which of the following value is the intrinsic impedance of free space?
a) 100 Ω
b) 50 Ω
c) 317 Ω
d) 377 Ω
e) 370 Ω
f) 277 Ω
Ans: (d)
235. The resultant magnetic flux generated in the closed surface will be
a) Zero
b) Continuous
c) Constant
d) Unity
Ans: (a)
236.If the current in induction coil varies from 10 A to 20 A in one second and induces the
voltage of 100 V, what will be the inductance of coil?
a) 10 H
b) 10 μH
c) 5 H
d) 1 H
e) 10 mH
f) 100 H
Ans: (a)
237. What will happen if electromagnetic wave is falling on a perfect dielectric?

a) The wave will be transmitted completely
b) The wave will be partially reflected and partly transmitted
c) The wave will be completely refracted
d) The wave will be partially absorbed
Ans: (b)
238. Which of the following gives the rate of energy flow?

a) Maxwell equation
b) Pointing vector
c) Poisson vector
d) Newton’s laws
Ans: (b)
239.The quality factor of an induction coil can be increased if

a) The length of the wire is increased
b) The diameter of wire decreased
c) The length of the wire is decreased
Ans: ()
240. Which of the following is normally designed for high value of quality factor?
a) Resistance
b) Inductance
c) Capacitance
Ans: (b)

a) Div curl B = ∞
b) Div curl A = 0
c) Div curl B = 1
d) Div curl B = B
Ans: (b)
242. If X = q/4πr2, which of the following parameter will be X?

a) Electric field strength
b) Magnetic field strength
c) Electric displacement density
d) Permeability
Ans: (c)
243. Which of the following expression is correct for electric field strength?
a) E = D
b) E = πD
c) E = D/ε
d) E = r/ε
Ans: (c)
244. Which of the following distance in terms of wavelength is correct if the distance is
measured between maxima and minima of standing wave?
a) λ/2
b) λ/8
c) 4λ
d) λ/4
Ans: (d)
245. Polarization in the electromagnetic waves is attributed to

a) absorptive nature of waves
b) reflection of waves
c) longitudinal nature of waves
d) transverse nature of waves
e) electric field of waves
Ans: (d)
246. Which of the equation represents the following wavefrom?

a) y = sin⁡x/3
b) x = 2 sin⁡3x/2
c) y = 2sin⁡3x
d) y = 2 sin⁡2x
e) y = 2 sin⁡x
Ans: (c)
247. If 0 < θ1 < θ2 < π/2, which of the following statement is true ?
a) sin⁡θ1 < sin⁡θ2
b) cos⁡θ1 < cos⁡θ2
c) tan⁡θ1 < tan⁡θ2
d) (a)and (c) only
e) (b) and (c) only
f) (a) and (b) only
Ans: (d)

a) The magnetic field inside the conductor is zero
b) The magnetic field inside the semiconductor is zero
c) The magnetic field inside superconductor is zero
d) The magnetic field inside the superconductor is zero
Ans: (c)
249. Wein Bridge may be used for

a) Resistance determination
b) Frequency measurements
c) Power factor measurements
d) Harmonic distortion analysis
e) Both (b) and (d)
Ans: (e)
250. The D’Arsonval instruments work on the principle of

b) Moving iron instruments
c) Potentiometric instruments
d) Permanent magnet moving coil instruments
e) Induction instruments
Ans: (d)
251. When any material has negative magnetism, the material is called as
a) Paramagnetic
b) Diamagnetic
c) Ferromagnetic
d) Antiferromagnetic
Ans: (b)
252. The bar magnet has

a) The dipole movement
b) Monopole movement
c) (a) and (c) both
Ans: (a)
253. There is no such material which has properties of magnetic monopole.

a) True
b) False
Ans: (b)
254. Which of the following materials are diamagnetic?

a) Copper
b) Silver
c) Copper and silver
d) Iron
Ans: (c)
255. When of the following material fall in the category of paramagnetic materials?
a) Copper
b) Iron
c) Copper and iron
d) Nickel
Ans: (d)
256. Which of the following type materials are not very important for engineering
applications?
a) Paramagnetic
b) Ferromagnetic
c) Diamagnetic
Ans: (c)
257. The solids which have small but positive magnetic susceptibility are called
a) Ferromagnetic
b) Paramagnetic
c) Diamagnetic
d) Anti-ferromagnetic
Ans: (b)
258. The susceptibility of paramagnetic materials generally lies between

a) 10-3 and 10-7
b) 10-3 and 10-5
c) 10-4 and 10-8
d) 10-2 and 10-5
Ans: (b)
259. For which of the following materials the saturation value is the highest?
a) Ferrites
b) Ferromagnetic materials
c) Paramagnetic materials
d) Diamagnetic materials
Ans: (a)
260. For which of the following materials the relative permeability is less than one?
a) Ferromagnetic materials
b) Diamagnetic materials
c) Paramagnetic materials
d) Ferrites
Ans: (b)
261. The temperature above which an anti-ferromagnetic material becomes paramagnetic is
called
a) Peak temperature
b) Critical temperature
c) Neel temperature
d) Weiss temperature
Ans: (c)
262. The inductance of the following circuit across A and B will be

a) L1+L2+M
b) L1+L2+2M
c) L1+L2-2M
d) L1+L2-M
Ans: (b)
263. The inductance of the following circuit across A and B will be

a) L1+L2-M
b) L1+L2+2M
c) L1+L2+M2-L1 L2
d) (L1 L2-M2)/(L1+L2+2M)
Ans: (b)
264. The transient currents may occur in following circuits

a) Pure resistive circuits
b) Capacitive circuits
c) RL circuits
d) RLC circuits
e) (b) or (c) or (d)
Ans: (e)
265. Which of the following coil will have large resonant frequency?
a) A coil with large distributed capacitance
b) A coil with low distributed capacitance
c) A coil with large resistance
d) A coil with low resistance
Ans: (a)
266. The transfer matrix |1&0 Y&1| belongs to which of the following circuits?
267. What will be the magnetic field in the toroid having N number of turns, diameter d and
current I
a) 1/2π NI/d
b) 1/π NI/d
c) μo/π NI/d
d) (μo IN)/(πd2 )
Ans: (c)
268. A variable AC source is connected across the resistor. Which of the following curve
represents correct relationship between W and voltage V, if voltage is increased gradually.
269. Atypical radar antenna will have the bandwidth of

a) 4°
b) 6°
c) 1°
d) 2°
Ans: (d)
270. Which of the following antenna is non-resonant?

a) Broadside array
b) Marconi
c) Discone
d) Rhombic
Ans: (d)
271.Ferrimagnetic materials are generally classified as
a) Conductors
b) Semiconductors
c) Dielectric
d) Insulators
Ans: (b)
272. Which of the material one will choose for transformer core if the transformer has to
work at microwave frequency?
a) Supermalloy
b) Silicon
c) Ferrites
d) Iron
Ans: (c)
273. The magnetic materials exhibit the property of magnetization because of

a) Orbital motion electrons b) Spin of electrons
c) Spin of nucleus
d) Either of these
e) All of the above
Ans: (c)
274. A coil of 0.04 mH is carrying current of 1 A. If this current is reversed in 0.02 seconds,
the induced emf in the coil will be
a) 0.16 V
b) 0.008 V
c) 0.004 V
d) 0.04 V
Ans: (c)
275. A coil wound on the iron core which carries current I. The self induced voltage in the
coil is not affected by
a) Change of number of turns of coil
b) The resistance of magnetic path
c) Variation in voltage to the coil
d) Variation in coil current
Ans: (c)
276. How much energy will be stored in the magnetic field of coil which has self inductance
of 10 mH and current of 20 A?
a) 1 joule
b) 10 joule
c) 2 joule
d) 20 joule
Ans: (c)

a) Inductance of the coil carrying a constant DC current will increase the current
b) The inductance of the coil carrying a constant DC current will not affect the current
c) The inductance of the coil carrying a constant DC current will decrease the current
d) The inductance of the coil carrying a constant Dc current will change the current into
pulses
Ans: (b)
278. If the frequency of power supply is 60 Hz, what will be the period of one cycle?
a) 0.02 sec
b) 0.015 sec
c) 0.017 sec
d) 0.03 sec
Ans: (c)
279. If a sinusoidal wave has frequency of 50 Hz with 15 A rms current which of the
following equation represents this wave
a) 15 sin⁡50 t
b) 30 sin⁡25 t
c) 42.42 sin⁡25 t
d) 21.21 sin⁡314 t
Ans: (d)
280. What will happen if the frequency of power supply in a pure capacitive circuit is
doubled?
a) The current will be reduced to half
b) The current will also be doubled
c) The current will remain same
d) The current will increase by fourfold
Ans: (b)
281. The safest value of current the human body can carry more than 3 seconds is
a) 5 mA
b) 15 mA
c) 25 mA
d) 35 mA
e) 9 mA
Ans: (e)
282. Which of the following precaution will be taken first if a man suffers from electric
shock?
a) Switch the power supply
b) Call the doctor
c) Make him lie on ground
d) Provide him glucose
e) Lie done on the ground and provide him artificial respiration
Ans: (e)
283. A transformer is designed to achieve 240 V AC 50 Hz supply with input of 3.3 kV, 50
Hz and output of 415 V 50 Hz. The secondary of the transformer will have
a) Three phase 3 wire system
b) Three phase 2 wire system
c) Thhee phase 6 wire system
d) Three phase 4 wire system
Ans: (d)
284. The hysteresis losses do not depend on

a) Volume of material
b) Magnetic field
c) Frequency
d) Either of them
e) None of these
Ans: (e)
285. For which of the following materials the net magnetic moment should be zero.
b) Diamagnetic materials
c) Anti-ferrimagnetic materials
d) Anti-ferromagnetic materials
Ans: (d)
286. What will happen if strong magnetic field is applied to ferromagnetic field?
a) The domain wall motion varies

b) The domain wall motion becomes constant
c) The domain wall motion becomes reversible
d) The domain wall motion becomes irreversible
Ans: (d)
287. The attraction capacity of electromagnet will

a) Increase if the flux density decreases
b) Increase if the flux density increases
c) Increase if the core area increases
d) Increase if the core length increases
Ans: (b)

a) The conductivity of ferromagnetic material is better than ferrites
b) The conductivity of ferrites is better than ferromagnetic materials
c) The conductivity of ferrites is same as that of ferromagnetic materials
d) The conductivity of ferrites is very high
Ans: (b)
289. The magnetization and applied field in ferromagnetic materials are related
a) Linearly
b) Non-linearly
c) Parabolically
d) Sinusoidally
Ans: (b)
290. The effective power in a pure capacitive circuit shall be

a) Energy stored by capacitor
b) Positive
c) Half of the energy stored
d) Zero
Ans: (d)
291. A pure inductance connected across 230 V 50 Hz supply consumes 50 W. this

consumption can be attributed to
a) The reactance of the inductor
b) The current flowing in the inductor
c) The big size of the inductor
d) The false statement made in this question
Ans: (d)
292. The heat generated by an electric iron is

a) Reactive power
b) True power
c) Apparent power
d) Reactive and power
Ans: (b)
293. In which of the materials the spin moments associated with two sets atoms are aligned
antiparallel to each other.
b) Anti-ferromagnetic materials
c) Ferrites
d) Ferromagnetic materials
Ans: (b)

a) Polarizer converts the produced hydrogen in the water in the carbon zinc battery
b) Depolarizer converts the produced hydrogen in the water in the carbon zinc battery
c) Carbon power converts the produced hydrogen in the water in the carbon zinc battery
d) Zinc chloride converts the produced hydrogen in the water in the carbon zinc battery
Ans: (b)
295. Manganese dioxide acts as depolarizer in

a) Lead acid battery
b) Carbon zinc cell
c) Dry cell
d) Zinc electrolyte cell
Ans: (c)
296. Which of the following acts as a depolarizer in carbon zinc cell?

a) Carbon power
b) Zinc chloride
c) Iron ore and carbon powder
d) Ammonia chloride
Ans: (c)
297. If the current is passed through a conductor which of the following phenomenon will be
observed?
a) The magnetic field will be developed in the conductor
b) The magnetic field and heat is developed in the conductor
c) The only heat is developed in the conductor
d) The molecules of the conductor attract each other
Ans: (b)
298. The standing wave ratio of 4 will be applicable to

a) 80 ohms transmission line feeding to a load of 320 ohms
b) 20 ohms transmission line feeding to a load of 100 ohms
c) 100 ohms transmission line feeding to a load of 300 ohms
d) 50 ohms transmission line feeding to a load of 500 ohms
Ans: (a)
299. A network which does not have either voltage source or current source is called
a) Active network
b) Passive network
c) Resistive network
d) Resistive and inductive network
Ans: (b)
1.The VTVM can be used to measure
a) d.c. voltage only

b) a.c. voltage of high frequency only
c) d.c. voltage and a.c. voltage upto the order of 5 MHz frequency
d) a.c. voltage of low frequency
Ans: (a)
2. An oscillator cannot be used as an X-Y plotter.

a) true
b) false
Ans: (b)
3. The forward resistance of the diode will be
a) zero
b) small
c) infinity
d) high
Ans: (b)
4. The vacuum tubes are

a) high voltage devices
b) low voltage and low current devices
c) high current devices
d) low current devices
Ans: (b)
5. The transistors are

a) high voltage devices
b) low voltage and low current devices
c) high current devices
d) low current devices
Ans: (b)
6. The voltage at which the electrons flow starts from the anode to cathode is called
a) breakdown voltage
b) peak inverse voltage
c) peak voltage
d) pinch off voltage
Ans: (b)
7. The energy needed to disrupt the bonds of pure germanium is

a) 1.12 eV
b) 0.75 eV
c) 0.6 eV
d) 7.5 eV
Ans: (b)
8. The lifetime of an electron of hole before recombination will be

a) ½ minute
b) ½ second
c) Less than microseconds to more than milliseconds depending on circumstances
d) ¼ second
e) Milliseconds
Ans: (c)
9. Which of the following doping will create the “p-type” semiconductor?

a) Germanium with phosphor
b) Silicon with Indium
c) Germanium with antimony
d) Germanium with Indium
Ans: (d)
10. The triode has

a) Two electrodes
b) Three electrodes
c) Four electrodes
Ans: (b)
11. The input to the triode is given between

a) Plate and grid
b) Plate and cathode
c) Grid and cathode
d) Plate and heater
Ans: (c)
12. The grid in the triode has

a) Negative potential
b) Positive potential
c) Negative potential but more positive than cathode
d) Negative potential but more negative than cathode
Ans: (c)
13. When the grid of the triode is negative

a) The plate current will increase
b) The plate current will decrease
c) The plate current will not be affected
d) The grid will attract more electrons
Ans: (b)
14. The term “No Signal” related to electron tubes usually indicates
a) Open grid circuit
b) Open plate circuit
c) Open cathode circuit
d) Signal of zero volt
Ans: (d)
15. The amplification of a signal by triode common-cathode amplifier will cease if

a) The grid is more positive
b) The grid is more negative than cutoff voltage
c) The plate is more positive
d) The plate is more negative
Ans: (b)

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1.

Transient response in the system is basically due to

2. Effect of feedback on the plant is to

3. Transfer function of a system is defined as the ratio of output to input in

4. In an open loop system

5. Transfer function of a system can used to study its

6. Electrical resistance is analogous to

7. Automatic control system in which output is a variable is called

8. Output of the feedback control system should be a function of

10. Relation between Fourier integral and Laplace transformer is through

11. At resonance peak, ratio of output to input is

12. 0 type system has

13. If gain of the system is zero, then the roots

16. If gain of the system is increased, then

17. A low value of friction coefficient

18. Physical meaning of zero initial condition is that the

19. If overshoot is excessive, then damping ratio is

21. For second order linear system, setting time is

a) 1/4 of the time constant

22. System generally preferred is

23. For unity damping factor, the system will be

24. Second-derivative input signal adjust

25. In the derivative error compensation

27. With feedback system sensitivity to parameter

28. In a closed loop system, source power is modulated with

29. With feedback system, transient response

30. Non-Linearity in the servo system due to saturation is caused by

31. In control system non-Linearity caused by gear trains is

33. Differential is used in synchro differential unit for generators only

34. Microsyn is the name given to

35. Laplace transformer is not applicable to non-linear system because

37. Liner differential transformer is an

40. Power amplification in a magnetic amplifier can be increased

41. Device used for conversion of coordinates is

42. Friction coefficient is usually kept low to

43. Most common use of the synchros is as

44. To decrease time of the servomechanism

48. Which of the following motor is suitable for servomechanism?

49. To decrease the number of system

50. Servomechanism with step-displacement input is

51. If feedback is introduced in the system the transient response

a) Does not very

52. Main difference between servomotor and standard motor is that

54. Self balancing instrument uses

55. Lead compensation in the system add

56. In type 1 system steady state acceleration error is

57. Lead lag compensation improve

62. To increase damping of pair of complex roots compensator used is

66. If a pole is added to a system it causes

68. For steady state transient improvement, compensator used is

74. Closed loop ples are

75. If gain is zero, then

76. Maximum over shoot is the function of

78. Feed back control system are basically

79. In root if 𝓴 is greater than critical value, then increasing 𝓴 will

80. A liner system obeys the principle of

81. Plot of the constant gain loci of the system is

83. In root locus technique, angle between adjacent asymptote is