THAKUR INSTITUE OF AVIATION TECHNOLOGY

MODULE 03 TEST -1
MARKS - 52 TIME: 65 MINS
1 The power factor of a circuit containing an imbalance of inductive and capacitive reactance is.   
1 Greater than unity     2 Zero
3 Less than unity.           4 Unity. 
2 A sine wave has 8 amps RMS value. What is the peak value?.
1 13.33 amps 2 11.31 amps
3 14.14 amps 4 10.33 amps
3 What is the wave shape of the x-axis input of a traversing oscilloscope image?
1 Rectangular 2 Triangular 
3 Square 4 None
4 In a purely resistive AC circuit, the current vector is
1 +90° out of phase with the voltage 2 In phase with the voltage vector.      
vector.   
3 -90° out of phase with the voltage 4 Out of phase with the voltage vector.
vector.    

5 A parallel circuit at resonance has

1 Minimum impedance.  2 Maximum impedance.
3 Zero impedance.         4 None
6 How many amperes will a 28-volt generator be required to supply to a circuit containing five lamps
in parallel, three of which have a resistance of 6 ohms each and two of which have a resistance of 5
ohms each?.                   
1 1 ampere.     2 25.23 amperes.          
3 1.11 amperes.  4 2.55 amperes
7 Which wave form is stepped positive and negative with unequal length sides?. 
1 Rectangular wave. 2 Trapezoidal wave.     
3 Saw tooth wave.        4 Sine wave
8 The Form Factor of an AC waveform can be found by   
1 Average value times the RMS value.  2 Average value divided by the RMS
value.    
3 RMS value divided by the average value 4 Total power
9 A sine wave has a periodic time of 0.5 milliseconds, what is its frequency?
1 200 Hz 2 2Khz. 
3 20Khz.           4 20Hz
10 In a resonant parallel circuit, current is.                    
1 Zero. 2 Minimum.      
3 Maximum.      4 None
11 What is the power factor in a purely resistive circuit?
1 Equal to 1.      2 Less than 1 but greater than zero.     
3 Greater than 1.           4 Zero
12 In an A.C circuit, what happens if frequency is reduced?
1 Inductive elements may be damaged 2 Capacitive elements may be damaged
3 There will be no effect.          4 None
13 What is the relationship between the voltage and the current in an A.C circuit containing resistance
and inductance?
1 Current lags voltage by 90°. 2 Current lags voltage by up to 90°.    
3 Current leads voltage by up to 90°.   4 None
14 In a parallel R, L, C circuit, the value of the capacitor is quadrupled, then the value of the impedance
would
1 Remain the same. 2 Reduced        
3 Increased.       4 None
 THAKUR INSTITUE OF AVIATION TECHNOLOGY
MODULE 03 TEST -1
MARKS - 52 TIME: 65 MINS
15 In a capacitive circuit, if the frequency is increased
1 Reactance remains the same.   2 Impedance increases. 
3 Current increases.  4 None
16 In a tuned circuit at resonance, the circuit will be
1 Resistive.         2 Capacitive.     
3 Inductive.       4 None
17 A circuit has a resistance of 50 ohms and an inductance of 0.5 Henry. If it is connected to a 115 volt
50 Hz supply the reactance will be.           
1 120 ohms 2 157 ohms
3 167 ohms 4 127 ohms
18 When a circuit with a series inductance and capacitance is at resonant frequency.       
1 The current in the circuit decreases.  2 The impedance of the circuit is such that
the voltage is in phase with the
current.   
3 The impedance of the circuit is such that 4 None
the voltage leads the current by exactly 90
degrees.       

19 Capacitive reactance is more when

1 Capacitance is less and frequency of 2 Capacitance is less and frequency of supply
supply is less is more
3 Capacitance is more and frequency of 4 Capacitance is more and frequency of
supply is less supply is more
20 A coil having an inductance of 0.6H is connected to a 120 V, 60Hz AC source. Neglecting
resistance, what is the effective current through the coil?
1 0.764 A 2 0.531 A
3 0.238 A 4 0.833 A
21 A 2µF capacitor is connected to a 120 V, 60Hz AC source. Neglecting resistance, what is the
effective current through the coil?
1 60.7 mA 2 90.5 mA
3 120.3 mA 4 228.7 mA
22 A 60 Ώ resistor, a 0.5 H inductor, and an 8µF capacitor are connected in series with a 120 V, 60 Hz
ac source. Calculate the impedance for this circuit.
1 122 Ώ 2 322 Ώ
3 222 Ώ 4 422 Ώ
23 Find the resonant frequency for the circuit having L = 0.5 H and C = 8µF
1 258.6 Hz 2 214.6 Hz
3 137.3 Hz 4 79.6 Hz
24

Find the value of RA, RB and RC

1 RA = 3 Ώ, RB= 1.0 Ώ and RC = 1.5 Ώ 2 RA = 6 Ώ, RB= 6.0 Ώ and RC = 4.5 Ώ
3 RA = 9 Ώ, RB= 5.0 Ώ and RC = 6.5 Ώ 4 RA = 3 Ώ, RB= 4.0 Ώ and RC = 6 Ώ
25 Frequency Response of an electric or electronics circuit allows us to see exactly how
 THAKUR INSTITUE OF AVIATION TECHNOLOGY
MODULE 03 TEST -1
MARKS - 52 TIME: 65 MINS
1 magnitude response changes at a particular 2 phase response changes at a particular
single frequency single frequency
3 Both 1 & 2 4 None
26 Reactance curve is basically a graph of individual reactance verses
1 Amplitude 2 Phase
3 Frequency 4 Time period
27 A high pass filter has.           
1 high impedance to high frequency, low 2 high impedance to both high and low
impedance to low frequency.         frequency.    
3 high impedance to low frequency, low 4 None of the above
impedance to high frequency.        
28 Which among the following get/s cancelled under the resonance condition in a.c. circuits, if
inductive and capacitive reactance’s are in parallel?
1 Reactance 2 Susceptance
3 Resistance 4 All of the above
29 What would be the value of power factor for series RLC circuit under the resonance?
1 0 2 0.5
3 1 4 Infinity
30 What is the current in the circuit with a resistance of 8 ohms, inductive reactance of 12 ohms,
capacitive reactance of 18 ohms with 20 volts applied across it?
1 10 amps. 2 5 amps.
3 2 amps. 4 1 amps.
31 In a Series RLC circuit if the frequency is below the resonant, the circuit is
1 Inductive 2 Capacitive
3 Resistive 4 Reactive
32 In a Series RLC circuit if the frequency is above the resonant, the circuit is
1 lagging 2 leading
3 unity 4 Zero
33 An alternating current generator is operating at 50 kVA in a circuit with a power factor of 0.8. The
real power is.                  
1 50 KW 2 40 KW
3 72 KW 4 None
34 A resonant circuit has a lower critical frequency of 7 kHz and an upper critical frequency of 13 kHz.
The bandwidth of the circuit is
1 13 KHz 2 4 KHz
3 20 KHz 4 7 KHz
35 If the resistance in parallel with a parallel resonant circuit is reduced, the bandwidth
1 Increase 2 Decrease
3 Become shaper 4 Disappear
36 In a series RLC circuit that is operating above the resonant frequency, the current
1 is in phase with the applied voltage 2 is zero
3 leads the applied voltage 4 Lags the applied voltage
37 If the value of C in a series RLC circuit is decreased, the resonant frequency
1 is not affected 2 is reduced to zero
3 increases 4 decreases
38 A certain series resonant circuit has a bandwidth of 2 kHz. If the existing coil is replaced with one
having a higher value of Q, the bandwidth will
1 be less selective 2 Increase
3 remain the same 4 Decrease
39 At resonance, the term bandwidth includes all frequencies that allow what percentage of maximum
 THAKUR INSTITUE OF AVIATION TECHNOLOGY
MODULE 03 TEST -1
MARKS - 52 TIME: 65 MINS
current to flow?
1 70.7 2 62.3
3 50 4 95.3
40 What is the high cutoff frequency for an RLC circuit that resonates at 2000 Hz and has a bandwidth
of 250 Hz?
1 1750 Hz 2 2250 Hz
3 2125 Hz 4 8.0 Hz
41 A capacitor consists of two
1 Insulation separated by a dielectric 2 Conductor separated by an insulator
3 Ceramic plates and one mica disc 4 Silver –coated insulator
42 The capacitance of a capacitor is NOT influence by
1 Plates thickness 2 Plate area
3 Plate separation 4 Nature of dielectric
43 A capacitor that stores a charge of 0.5 Cat 10volts has a capacitance of ………farad.
1 5 2 20
3 10 4 0.05
44 Unit of magnetic flux is
1 Weber 2 Ampere-turn
3 Tesla 4 coulomb
45 The 3rd Band from left to right in a resistor indicate
1 1st value 2 multiplier
3 Tolerance 4 error
46 In radio and radar transmission …………….enough to cause arcing or breakdown.
1 Current less 2 Voltage less
3 Voltage high 4 None of above
47 Smallest particles exists are called
1 Molecules 2 atom
3 Element 4 None of above
48 If the third band is gold in colour, the first two digits must be multiplied by ………percent.
1 4 2 6
3 10 4 None of above
49 Under frequency in an AC supply would cause.
1 overheating of inductive devices 2 overheating of capacitive devices
3 Over speed of AC motors 4 None
50 In a Delta connected generator the line current is equal to.             
1 1.7 x phase voltage 2 phase current
3 1.7 x phase current 4 None
51 Calculate the speed of a 372 Hz, 8 pole machine.                
1 5000 RPM 2 5520 RPM
3 5580 RPM 4 None
52 The difference in speed between a synchronous motor's rotor and stator is known as
1 phase lag.       2 slip speed.     
3 rotor lag.         4 None