Heating Welding

Question Bank (short Questions)
Subject : UEET (2160907)
Electric Heating and Electric Welding
1. Which of the following is an advantage of heating by
electricity ?
(a) Quicker operation
(b) Higher efficiency
(c) Absence of flue gases
(d) All of the above
Ans: d
2. ________ has the highest value of thermal conductivity.
(a) Copper
(b) Aluminium
(c) Brass
(d) Steel
Ans: a
3. Which of the following heating methods has maximum power factor ?
(a) Arc heating
(b) Dielectric heating
(c) Induction heating
(d) Resistance heating
Ans: d
4 method has leading power factor
 Dr. Subhash Technical Campus- A Jewel of Junagadh 

(a) Resistance heating
(c) Arc heating
(d) Induction heating
Ans: b
5 is used for heating non-conducting materials.
(a) Eddy current heating
(b) Arc heating
(c) Induction heating
(d) Dielectric heating
Ans: d
6. Which of the following methods of heating is not
dependent on the frequency of supply ?
(a) Induction heating
(c) Electric resistance heating
Ans: c
7. When a body reflects entire radiation incident on it,
then it is known as
(a) white body

(b) grey body
(c) black body
(d) transparent body
Ans: a
8. For the transmission of heat from one body to another
(a) temperature of the two bodies must be different
(b) both bodies must be solids
(c) both bodies must be in contact
(d) at least one of the bodies must have some source of
heating
Ans: a
9. Heat transfer by condition will not occur when
(a) bodies are kept in vacuum
(b) bodies are immersed in water
(c) bodies are exposed to thermal radiations
(d) temperatures of the two bodies are identical
Ans: d
10. A perfect black body is one that
(a) transmits all incident radiations
(b) absorbs all incident radiations
(c) reflects all incident radiations
(d) absorbs, reflects and transmits all incident radiations
Ans: b

11. Heat is transferred simultaneously by condition,
convection and radiation
(a) inside boiler furnaces
(b) during melting of ice
(c) through the surface of the insulted pipe carrying steam
(d) from refrigerator coils to freezer of a refrigerator
Ans: a
12. The process of heat transfer during the reentry of
satellites and missiles, at very high speeds, into earth’s atmosphere is known
as
(a) ablation
(b) radiation
(c) viscous dissipation
(d) irradiation
Ans: a
13. Which of the following has the highest value of
thermal conductivity ?
(a) Water
(b) Steam
(c) Solid ice
(d) Melting ice
Ans: c

14. Induction heating process is based on which of the
following principles ?
(a) Thermal ion release principle
(b) Nucleate heating principle
(c) Resistance heating principle
(d) Electro-magnetic induction princi¬ple
Ans: d
15. Which of the following insulating materials was
suitable for low temperature applications ?
(a) Asbestos paper
(b) Diatomaceous earth
(c) 80 percent magnesia
(d) Cork
Ans: b
16. A non-dimensional number generally associated with
natural convection heat transfer is
(a) Prandtl number
(b) Grashoff number
(c) Pecelet number
(d) Nusselt number
Ans: b
17. The temperature inside a furnace is usually measured
by which of the following ?

(a) Optical pyrometer
(b) Mercury thermometer
(c) Alcohol thermometer
(d) Any of the above
Ans: a
18. Which of the following will happen if the thickness of
refractory wall of furnace is increased ?
(a) Heat loss through furnace wall will increase
(b) Temperature inside the furnace will fall
(c) Temperature on the outer surface of furnace walls will
drop
(d) Energy consumption will increase
Ans: c
19. The material of the heating element for a furnace
should have
(a) lower melting point
(b) higher temperature coefficient
(c) high specific resistance
(d) all of the above
Ans: c
20. In a resistance furnace the atmosphere is
(a) oxidising
(b) deoxidising

(c) reducing
(d) neutral
Ans: a
21. By which of the following methods the temperature
inside arc nace can be varied ?
(a) By disconnecting some of the heating elements
(b) By varying the operating voltage
(c) By varying the current through heating elements
(d) By any of the above method
Ans: d
22. In induction heating ______ is abnormally high.
(a) phase angle
(b) frequency
(c) current
(d) voltage
Ans: b
23. By the use of which of the following, high frequency
power supply for induction furnaces can be obtained ?
(a) Coreless transformers
(b) Current transformers
(c) Motor-generator set
(d) Multi-phase transformer
Ans: c

24. Induction furnaces are employed for which of the
following ?
(a) Heat treatment of castings
(b) Heating of insulators
(c) Melting aluminium
(d) None of the above
Ans: a
25. In an electric room heat convector the method of
heating used is
(a) arc heating
(b) resistance heating
(c) induction heating
(d) dielectric heating
Ans: b
26. In a domestic cake baking oven the temperature is
controlled by
(a) voltage variation
(b) thermostat
(c) auto-transformer
(d) series-parallel operation
Ans: d
27. In an electric press mica is used

(a) as an insulator
(b) as a device for power factor improvement
(c) for dielectric heating
(d) for induction heating
Ans: a
28. Induction heating takes place iitwhich of the
following ?
(a) Insulating materials
(b) Conducting materials which are magnetic
(c) Conducting materials which are non-magnetic
(d) Conducting materials which may or may not be magnetic
Ans: d
29. For heating element high resistivity material is
chosen to
(a) reduce the length of heating element
(b) increase the life of the heating element
(c) reduce the effect of oxidation
(d) produce large amount of heat
Ans: a
30. In resistance heating highest working temperature is
obtained from heating elements made of
(a) nickel copper
(b) nichrome

(c) silicon carbide
(d) silver
Ans: c
31. For intermittent work which of the following furnaces
is suitable ?
(a) Indirect arc furnace
(b) Core less furnace
(c) Either of the above
Ans: a
32. Due to which of the following reasons it is desirable
to have short arc length ?
(a) To achieve better heating
(b) To increase the life of roof refractory
(c) To have better stirring action
(d) To reduce problem of oxidation
(e) All of the above
Ans: e
33. In the indirect resistance heating method, maximum
heat-transfer takes place by
(a) radiation
(b) convection
(c) conduction

(d) any of the above
Ans: a
34. Properly of low temperature co-eflficient of heating
element is desired due to which of the following reasons ?
(a) To avoid initial rush of current
(b) To avoid change in kW rating with temperature
(c) Both (a) and (b)
(d) Either (a) or (b)
Ans: c
35. Which of the following methods is used to control
temperature in resistance furnaces ?
(a) Variation of resistance
(b) Variation of voltage
(c) Periodical switching on and off of the supply
(d) All of the above methods
Ans: d
36. It is desirable to operate the arc furnaces at power
factor of
(a) zero
(b) 0.707 lagging
(c) unity
(d) 0.707 leading
Ans: b

37. Radiations from a black body are proportional to
(a) T1
(b) T2
(c) T3
(d) T*
Ans: d
38. In arc furnace the function of choke is
(a) to stabilize the arc
(b) to imprpve, power factor
(c) to reduce severity of the surge
(d) none of the above
Ans: a
39. Ajax Wyatt furnace is started when
(a) it is filled below core level
(b) it is filled above core level
(c) it is fully empty
Ans: b
40. In electric press, mica is used because it is _______
conductor of heat but/and ________ conductor of electricity.
(a) bad, good
(b) bad, bad

(c) good, bad
(d) good, good
Ans:
41. Resistance variation method of temperature control is
done by connecting resistance elements in
(a) series
(b) parallel
(c) series-parallel connections
(d) star-delta connections
(e) all of the above ways
Ans: e
42. Hysteresis loss and eddy current loss are used in
(a) induction heating of steel
(b) dielectric heating
(c) induction heating of brass
(d) resistance heating
Ans: a
43. In heating the ferromagnetic material by induction
heating, heat is produced due to
(a) induced current flow through the charge
(b) hysteresis loss taking place below curie
temperature
(c) due to hysteresis loss as well as eddy current loss

takingplace in the charge
(d) none of the above factors
Ans: c
44. Radiant heating is used for which of the following ?
(a) Annealing of metals
(b) Melting of ferrous metals
(c) Heating of liquids in electric kettle
(d) Drying of paints and varnishes
Ans: d
45. Which of the following devices is necessarily required
for automatic temperature control in a furnace ?
(a) Thermostat
(b) Thermocouple
(c) Auto-transformer
(d) Heating elements of variable resis-tance material
Ans: b
46. For radiant heating around 2250°C, the heating
elements are made of
(a) copper alloy
(b) carbon
(c) tungsten alloy
(d) stainless steel alloy
Ans: c

47. Which of the following is an advantage of eddy current
heating ?
(a) The amount of heat generated can be controlled accurately
(b) Heat at very high rate can be gene-rated
(c) The area of the surface over which heat is produced can
be accurately controlled
Ans: d
48. The electrode of a direct arc furnace is made of
(a) tungsten
(b) graphite
(c) silver
(d) copper
Ans: b
49. Direct arc furnaces have which of the following power
factors ?
(a) Unity
(b) Low, lagging
(c) Low, leading
Ans: b
50. In direct arc furnace, which of the following has high

value ?
(a) Current
(b) Voltage
(c) Power factor
Ans: a
Electric Traction
1. Which of the following is an advantage of electric traction over other
methods of traction ?
(a) Faster acceleration
(b) No pollution problems
(c) Better braking action
Ans: a
2. Which of the following is the voltage for single phase A.C. system ?
(a) 22 V
(b) 440 V
(c) 5 kV
(d) 15 kV
(e) None of the above
Ans: a
3. Long distance railways use which of the following ?
(a) 200 V D.C.
(b) 25 kV single phase A.C.
(c) 25 kV two phase A.C.
(d) 25 kV three phase A.C.

Ans: b
4. The speed of a locomotive is controlled by
(a) flywheel
(b) gear box
(c) applying brakes 11.
(d) regulating steam flow to engine
Ans:
5. Main traction systems used in India are, those using
(a) electric locomotives
(b) diesel engine locomotives
(c) steam engine locomotives
(d) diesel electric locomotives
(e) all of the above
Ans: e
6, in India diesel locomotives are manufactured at
(a) Ajmer
(b) Varanasi
(c) Bangalore
(d) Jamalpur
Ans: b
7. For diesel locomotives the range of horsepower is
(a) 50 to 200
(b) 500 to 1000
(c) 1500 to 2500
(d) 3000 to 5000
Ans: c

8. _______ locomotive has the highest operational availability.
(a) Electric
(b) Diesel
(c) Steam
Ans: a
9. The horsepower of steam locomotives is
(a) up to 1500
(b) 1500 to 2000
(c) 2000 to 3000
(d) 3000 to 4000
Ans: a
10. The overall efficiency of steam locomotive is around
(a) 5 to 10 percent
(b) 15 to 20 percent
(c) 25 to 35 percent
(d) 35 to 45 percent
Ans: a
11. In tramways which of the following motors is used ?
(a) D.C. shunt motor
(b) D.C. series motor
(c) A.C. three phase motor
(d) AC. single phase capacitor start motor
Ans: b
12. In a steam locomotive electric power is provided through
(a) overhead wire
(b) battery system

(c) small turbo-generator
(d) diesel engine generator
Ans: c
13. Which of the following drives is suitable for mines where explosive
gas exists ?
(a) Steam engine
(b) Diesel engine
(c) Battery locomotive
Ans: c
14. In case of locomotives the tractive power is provided by
(a) single cylinder double acting steam engine
(b) double cylinder, single acting steam engine
(c) double cylinder, double acting steam engine
(d) single stage steam turbine
Ans: c
15. Overload capacity of diesel engines is usually restricted to
(a) 2 percent
(b) 10 percent
(c) 20 percent
(d) 40 percent
Ans: a
16. In case of steam engines the steam pressure is
(a) 1 to 4 kgf/cm2
(b) 5 to 8 kgf/cm2
(c) 10 to 15 kgf/cm2

(d) 25 to 35 kgf/cm2
Ans: c
17.. The steam engine provided on steam locomotives is
(a) single acting condensing type
(b) single acting non-condensing type
(e) double acting condensing type
(d) double acting non-condensing type
Ans: b
18. Electric locomotives in India are manufactured at
(a) Jamalpur
(b) Bangalore
(c) Chittranjan
(d) Gorakhpur
Ans: c
19. The wheels of a train, engine as well as bogies, are slightly tapered
to
(a) reduce friction
(b) increase friction
(c) facilitate braking
(d) facilitate in taking turns
Ans: d
20. Automatic signalling is used for which of the following trains ?
(a) Mail and express trains
(b) Superfast trains
(c) Suburban and Urban electric trains
(d) All trains

Ans: b
21. The efficiency of diesel locomotives is nearly
(a) 20 to 25 percent
(b) 30 to 40 percent
(c) 45 to 55 percent
(d) 60 to 70 percent
Ans: a
22. The speed of a superfast train is
(a) 60 kmph
(b) 75 kmph
(c) 100 kmph
(d) more than 100 kmph
Ans: d
23. The number of passenger coaches that can be attached to a diesel
engine locomotive on broad gauge is usually restricted to
(a) 5
(b) 10
(c) 14
(d) 17
Ans: b
24. Which of the following state capitals is not on broad gauge track ?
(a) Lucknow
(b) Bhopal
(c) Jaipur
(d) Chandigarh
Ans: c

25. Which of the following is the advantage of electric braking ?
(a) It avoids wear of track
(b) Motor continues to remain loaded during braking
(c) It is instantaneous
(d) More heat is generated during braking
Ans: a
Which of the following braking systems on the locomotives is costly ?
(a) Regenerative braking on electric locomotives
(b) Vacuum braking on diesel locomotives
(c) Vacuum braking on steam locomotives
(d) All braking systems are equally costly
Ans: a
27. Tractive effort is required to
(a) overcome the gravity component of train mass
(b) overcome friction, windage and curve resistance
(c) accelerate the train mass
(d) do all of the above
Ans: d
28. For given maximum axle load tractive efforts of AC. locomotive will
be
(a) less than that of D.C. locomotive
(b) more than that of D.C. locomotive
(c) equal to that of D.C. locomotive
Ans: b
29. Co-efficient of adhesion reduces due to the presence of which of the

following ?
(a) Sand on rails
(b) Dew on rails
(c) Oil on the rails
(d) both (b) and (c)
Ans: d
30. Due to which of the following co-efficient of adhesion improves ?
(a) Rust on the rails
(b) Dust on the rails
(c) Sand on the rails
Ans: d
31. Quadrilateral speed-time curve pertains to which of the following
services ?
(a) Main line service
(b) Urban service
(c) Sub-urban service
(d) Urban and sub-urban service
Ans: d
32. Which of the following is the disadvantage of electric traction over
other systems of traction ?
(a) Corrosion problems in the under-ground pipe work
(b) Short time power failure interrupts traffic for hours
(c) High capital outlay in fixed installations beside route limitation
(d) Interference with communication lines
(c) All of the above

Ans: c
33. Co-efficient of adhesion is
(a) high in case of D.C. traction than in the case of AC. traction
(b) low in case of D.C. traction than in the case of AC. traction
(c) equal in both AC. and D.C. traction
Ans: b
34. Speed-time curve of main line service differs from those of urban and
suburban services on following account
(a) it has longer free running period
(b) it has longer coasting period
(c) accelerating and braking periods are comparatively smaller
Ans: d
35. The rate of acceleration on suburban orurban services is restricted
by the consideration of
(a) Engine power
(b) Track curves
(c) Passenger Discomfort
(d) Track size
Ans: c
36. The specific energy consumption of a train depends on which of the
following ?
(a) Acceleration and retardation
(b) Gradient
(c) Distance covered

Ans: d
37. The friction at the track is proportional to
(a) 1/speed
(b) l/(speed)2
(c) speed
Ans: c
38. The air resistance to the movement of the train is proportional to
(a) speed
(b) (speed)
(c) (speed)
(d) 1/speed
Ans: b
39. The normal value of adhesion friction is
(a) 0.12
(b) 0.25
(c) 0.40
(d) 0.75
Ans: b
40. The pulsating torque exerted by steam locomotives causes which of the
following?
(a) Jolting and skidding
(b) Hammer blow
(c) Pitching

Ans: a
41. Which of the following braking systems is used on steam locomotives ?
(a) Hydraulic system
(b) Pneumatic system
(c) Vacuum system
Ans: c
42. Vacuum is created by which of the following?
(a) Vacuum pump
(b) Ejector
(c) Any of the above
Ans: c
43. The resistance encountered by a train in motion is on account of
(a) resistance offered by air
(b) friction at the track
(c) friction at various parts of the rolling stock
Ans: d
44. Battery operated trucks are used in
(a) steel mills
(b) power stations
(c) narrow gauge traction
(d) factories for material transportation
Ans: d
45 method can bring the locomotive to dead stop.

(a) Plugging braking
(b) Rheostatic braking
(c) Regenerative braking
Ans: a
46. The value of co-efficient of adhesion will be high when rails are
(a) greased
(b) wet
(c) sprayed with oil
(d) cleaned with sand
Ans: d
47. The voltage used for suburban trains in D.C. system is usually
(a) 12 V
(b) 24 V
(c) 220 V
(d) 600 to 750 V
Ans: d
48. For three-phase induction motors which of the following is the least
efficient method of speed control ?
(a) Cascade control
(b) Pole changing
(c) Rheostat control
(d) Combination of cascade and pole changing
Ans: c
49. Specific energy consumption becomes
(a) more on steeper gradient

(b) more with high train resistance
(c) less if distance between stops is more
Ans: d
50. In main line service as compared to urban and suburban service
(a) distance between the stops is more
(b) maximum speed reached is high
(c) acceleration and retardation rates are low
Ans: d
51. Locomotive having monomotor bogies
(a) has better coefficient of adhesion
(b) are suited both for passanger as well as freight service
(c) has better riding qualities due to the reduction of lateral forces
(d) has all above qualities
Ans: d
52. Series motor is not suited for traction duty due to which of the
following account ?
(a) Less current drain on the heavy load torque
(b) Current surges after temporary switching off supply
(c) Self relieving property
(d) Commutating property at heavy load
Ans: b
53. When a bogie negotiates a curve, reduction in adhesion occurs
resulting in sliding. Thus sliding is acute when
(a) wheel base of axles is more

(b) degree of curvature is more
(c) both (a) and (b)
Ans: c
54. Energy consumption in propelling the train is required for which of
the following?
(a) Work against the resistance to motion
(b) Work against gravity while moving up the gradient
(c) Acceleration
Ans: d
55. An ideal traction system should have
(a) easy speed control
(b) high starting tractive effort
(c) equipment capable of with standing large temporary loads
Ans: d
56 have maximum unbalanced forces
(a) Diesel shunters
(b) Steam locomotives
(c) Electric locomotives
(d) Diesel locomotives
Ans: b
57. Specific energy consumption is affected by which of the following
factors ?
(a) Retardation and acceleration values

(b) Gradient
(c) Distance between stops
Ans: d
58. In case of ________ free running and coasting periods are generally
long.
(a) main-line service
(b) urban service
(c) sub-urban service
Ans: a
59. Overhead lines for power supply to tramcars are at a minimum height
of
(a) 3 m
(b) 6 m
(c) 10 m
(d) 15 m
Ans: c
60. The return circuit for tramcars is through
(a) neutral wire
(b) rails
(c) cables
(d) common earthing
Ans: b
61. Specific energy consumption is least in _______ service.
(a) main line

(b) urban
(c) suburban
Ans: a
62. Locomotives with monometer bogies have
(a) uneven distribution of tractive effect
(b) suitability for passanger as well as freight service
(c) lot of skidding
(d) low co-efficient of adhesion
Ans: b
63 _______ was the first city in India to adopt electric traction.
(a) Delhi
(b) Madras
(c) Calcutta
(d) Bombay
Ans: d
64 _______ frequency is not common in low frequency traction system
(a) 40 Hz
(b) 25 Hz
(c) 16 Hz
Ans: a
65. For 25 kV single phase system power supply frequency is
(a) 60 Hz
(b) 50 Hz
(c) 25 Hz
(d) 16 Hz
Ans: b

66. Power for lighting in passanger coach, in a long distance electric
train, is provided
(a) directly through overhead electric line
(b) through individual generator of bogie and batteries
(c) through rails
(d) through locomotive
Ans: b
67. In India, electrification of railway track was done for the first
time in which of the following years ?
(a) 1820—1825
(b) 1880—1885
(c) 1925—1932
(d) 1947—1954
Ans: c
68. Suri transmission is
(a) electrical-pneumatic
(b) mechanical-electrical
(c) hydro-mechanical
(d) hydro-pneumatic
Ans: c
69. In case of a steam engine an average coal consumption per km is
nearly
(a) 150 to 175 kg
(b) 100 to 120 kg
(c) 60 to 80 kg
(d) 28 to 30 kg

Ans: d
70. Which of the following happens in Kando system ?
(a) Three phase A.C. is converted into D.C.
(b) Single phase A.C. is converted into D.C.
(c) Single phase supply is converted into three phase system
Ans: c
71. For which of the following locomotives the maintenance requirements
are the least?
(a) Steam locomotives
(b) Diesel locomotives
(c) Electric locomotives
(d) Equal in all of the above
Ans: b
72. Which of the following methods is used to control speed of 25 kV, 50
Hz single phase traction ?
(a) Reduced current method
(b) Tap changing control of transformer
(c) Series parallel operation of motors
Ans: b
73. If the co-efficient of adhesion on dry rails is 0.26, which of the
following could be the value for wet rails ?
(a) 0.3
(b) 0.26
(c) 0.225

(d) 0.16
Ans: d
74 watt-hours per tonne km is usually the specific energy consumption for
suburban services.
(a) 15—20
(b) 50—75
(c) 120—150
(d) 160—200
Ans: b
75. The braking retardation is usually in the range
(a) 0.15 to 0.30 km phps
(b) 0.30 to 0.6 km phps
(c) 0.6 to 2.4 km phps
(d) 3 to 5 km phps
(e) 10 to 15 km phps
Ans: d
79. The rate of acceleration on suburban orurban service is in the range
(a) 0.2 to 0.5 km phps
(b) 1.6 to 4.0 km phps
(c) 5 to 10 km phps
(d) 15 to 25 km phps
Ans: b
80. The coasting retardation is around
(a) 0.16 km phps
(b) 1.6 km phps
(c) 16 km phps

(d) 40 km phps
Ans: a
Electric Drive
1. The selection of an electric motor for any application
depends on which of the following factors ?
(a) Electrical characteristics
(b) Mechanical characteristics
(c) Size and rating of motors
(d) Cost
Ans: e
2. For a particular application the type of electric-and
control gear are determined by which of the following considerations ?
(a) Starting torque
(b) Conditions of environment
(c) Limitation on starting current
(d) Speed control range and its nature
Ans: e
3. Which ofthefollowingmotors is preferred for traction work
(a) Universal motor

(c) Synchronous motor
(d) Three-phase induction motor
Ans:
4 Which of the following motors always starts on load ?
(a) Conveyor motor
(b) Floor mill motor
(c) Fan motor
Ans: d
5 is preferred for automatic drives.
(a) Squirrel cage induction motor
(b) Synchronous motors
(c) Ward-Leonard controlled D.C. motors
Ans: c
6. When the load is above _____ a synchronous motor is found to be more
economical.
(a) 2 kW
(b) 20 kW
(c) 50 kW
(d) 100 kW

Ans: d
7. The load cycle for a motor driving a power press will
be
(a) variable load
(b) continuous
(c) continuous but periodical
(d) intermittent and variable load
Ans: d
8. Light duty cranes are used in which of the following ?
(a) Power houses
(b) Pumping stations
(c) Automobile workshops
Ans: d
9. While selecting an electric motor for a floor mill,
which electrical characteristics will be of least significance ?
(a) Running characteristics
(b) Starting characteristics
(c) Efficiency
(d) Braking
Ans: d
10. Which of the following motors are pre-ferred for overhead

travelling cranes ?
(a) Slow speed motors
(b) Continuous duty motors
(c) Short time rated motors
Ans: c
11 is preferred for synthetic fibre mills.
(a) Synchronous motor
(b) Reluctance motor
(c) Series motor
(d) Shunt motor
Ans: b
12. Ward-Leonard controlled D.C. drives are generally used
for ______ excavators.
(a) Light duty
(b) Medium duty
(c) Heavy duty
Ans: c
13. Which of the following motors is used for elevators ?
(a) Induction motor
(b) Synchronous motor
(c) Capacitor start single phase motor

Ans: a
14. Which part of a motor needs maximum attention for
maintenance ?
(a) Frame
(b) Rearing
(c) Stator winding
(d) Rotor winding
Ans: b
15 need frequent starting and stopping of electric motors,
(a) Paper mills
(b) Grinding mills
(c) Air-conditioners
(d) Lifts and hoists
Ans: d
16. Which feature, while selecting a.motor for centrifugal
pump, will be of least significance ?
(a) Starting characteristics
(b) Operating speed
(c) Horse power
(d) Speed control
Ans: d

17. _______ motor is a constant speed motor.
(b) Schrage motor
(c) Induction motor
(d) Universal motor
Ans: a
18. The starting torque in case of centrifugal pumps is
generally
(a) less than running torque
(b) same as running torque
(c) slightly more than running torque
(d) double the running torque
Ans: a
19. Which of the following motors are best for the rolling
mills ?
(a) Single phase motors
(b) Squirrel cage induction motors
(c) Slip ring induction motors
(d) D.C. motors
Ans: d
20 is not a part of ball bearing ?
(a) Inner race
(b) Outer race

(c) Cage
(d) Bush
Ans: d
21. The starting torque of a D.C. motor is independent of which of the
following?
(a) Flux
(b) Armature current
(c) Flux and armature current
(d) Speed
Ans: d
22. Rotor of a motor is usually supported on _______
bearings.
(a) ball or roller
(b) needle
(c) bush
(d) thrust
Ans: a
23. For which of the following applications D.C. motors
are still preferred ?
(a) High efficiency operation
(b) Reversibility
(c) Variable speed drive
(d) High starting torque

Ans: c
24. In a paper mill where constant speed is required
(a) synchronous motors are preferred
(b) A.C. motors are preferred
(c) individual drive is preferred
(d) group drive is preferred
Ans: c
25. A reluctance motor
(a) is provided with slip rings
(b) requires starting gear
(c) has high cost
(d) is compact
Ans: d
26. The size of an excavator is usually expressed in terms
of
(a) ‘crowd’ motion
(b) angle of swing
(c) cubic metres
(d) travel in metres
Ans: c
27. For blowers which of the following motor is preferred

(a) D.C. series motor
(b) D.C. shunt motor
(c) Squirrel cage induction motor
(d) Wound rotor induction motor
Ans: b
28. Belted slip ring induction motor is almost invariably
used for
(a) water pumps
(b) jaw crushers
(c) centrifugal blowers
Ans: b
29. Which of the following is essentially needed while
selecting a motor ?
(a) Pulley
(b) Starter
(c) Foundation pedal
(d) Bearings
Ans: b
30. Reluctance motor is a
(a) variable torque motor
(b) low torque variable speed motor
(c) self starting type synchronous motor

(d) low noise, slow speed motor
Ans: c
31 method of starting a three phase induction motor needs
six terminals.
(a) Star-delta
(b) Resistance starting
(c) Auto-transformer
Ans: a
32. In ______ method of staging three phase induction
motors the starting voltage is not reduced.
(a) auto-transformer
(b) star-delta
(c) slip ring
Ans: c
33. In jaw crushers a motor has to often start against
______ load.
(a) heavy
(b) medium
(c) normal
(d) low
Ans: a

34. For a motor-generator set which of the following
motors will be preferred ?
(b) Slip ring induction motor
(c) Pole changing induction motor
(d) Squirrel cage induction motor
Ans: a
35. Which of the following motors is usually preferred for
kiln drives ?
(a) Cascade controlled A.C. motor
(b) Slip ring induction motor
(c) Three phase shunt wound
com-mutator motor
Ans: d
36. Heat control switches are used in
(a) transformers
(b) cooling ranges
(c) three phase induction motors
(d) single phase
Ans: b
37 has relatively wider range of speed control.

(6) Ship ring induction motor
(d) D.C. shunt motor
Ans: d
38. In squirrel cage induction motors which of the following
methods of starting cannot be used ?
(a) Resistance in rotor circuit
(b) Resistance in stator circuit
(c) Auto-transformer starting
(d) Star-delta starting
Ans: a
39. In which of the following applications the load on
motor changes in cyclic order ?
(a) Electric shovels
(b) Cranes
(c) Rolling mills
Ans: d
40. Flame proof motors are used in
(a) paper mills
(b) steel mills
(c) moist atmospheres

(d) explosive atmospheres
Ans: d
41. Which of the following machines has heavy fluctuation
of load ?
(a) Printing machine
(b) Punching machine
(c) Planer
(d) Lathe
Ans: b
42. For derries and winches which of the following drives
can be used ?
(a) Pole changing squirrel cage motors
(b) D.C. motors with Ward-leonard con-trol
(c) A.C. slip ring motors with variable resistance
Ans: d
43. Battery operated scooter for braking uses
(a) plugging
(b) mechanical braking
(c) regenerative braking
(d) rheostatic braking
Ans: b

44 has least range of speed control.
(a) Slip ring induction motor
(c) D.C. shunt motor
(d) Schrage motor
Ans: b
45 has the least value of starting torque to full load
torque ratio.
(a) D.C. shunt motor
(d) Slip ring induction motor
Ans: c
46. In case of _______ speed control by injecting e.m.f.
in the rotor circuit is possible,
(a) d.c. shunt motor
(b) schrage motor
(c) synchronous motor
(d) slip ring induction motor
Ans: d
47. A pony motor is used for the starting which of the
following motors ?
(a) Squirel cage induction motor

(b) Schrage motor
(c) Synchronous motor
Ans: c
48. In ________ the speed can be varied by
changing the position of brushes.
(a) slip ring motor
(b) schrage motor
(c) induction motor
(d) repulsion motor
Ans: b
49. In which of the following applications variable speed
operation is preferred ?
(a) Exhaust fan
(b) Ceiling fan
(c) Refrigerator
(d) Water pump
Ans: b
50. Heavy duty cranes are used in
(a) ore handling plants
(b) steel plants
(c) heavy engineering workshops

Ans: d
51. The travelling speed of cranes varies from
(a) 20 to 30 m/s
(b) 10 to 15 m/s
(c) 5 to 10 m/s
(d) 1 to 2.5 m/s
Ans: d
52. Besides a constant speed a synchronous rotor possesses
which of the following advantages ?
(a) Lower cost
(b) Better efficiency
(c) High power factor
Ans: c
53. By the use of which of the
followingm D.C. can be obtained from AC. ?
(a) Silicon diodes
(b) Mercury arc rectifier
(c) Motor generator set
Ans: d
54. Which of the following motors is preferred when quick

speed reversal is the main consideration ?
(a) Squirrel cage induction motor
(b) Wound rotor induction motor
(e) Synchronous motor
(d) D.C. motor
Ans: d
55. Which ofthefollowing motors is preferred when smooth
and precise speed control over a wide range is desired ?
(a) D.C. motor
(b) Squirrel cage induction motor
(c) Wound rotor induction motor
(d) Synchronous motor
Ans: a
56. For crane travel which of the following motors is
normally used ?
(b) D.C. differentially compound motor
(c) Ward-Leonard controlled D.C. shunt motor
(d) AC. slip ring motor
Ans: d
57. The capacity of a crane is expressed in terms of
(a) type of drive
(b) span

(c) tonnes
Ans: c
58. The characteristics of drive for crane hoisting and
lowering are which of the following ?
(a) Precise control
(b) Smooth movement
(c) Fast speed control
Ans: d
59. Which of the following motors is preferred for boom
hoist of a travelling crane ?
(a) Single phase motor
(c) A.C. slip ring motor
(d) Ward-Leonard controlled D.C. shunt motor
Ans: c
60. A wound rotor induction motor is preferred, as
compared to squirrel cage induction motor, when major consideration is
(a) slop speed operation
(b) high starting torque
(c) low windage losses

Ans: b
61. Which of the following motors has series
characteristics ?
(a) Shaded pole motor
(b) Repulsion motor
(c) Capacitor start motor
Ans: b
62. Which of the following happens when star-delta starter
is used ?
(a) Starting voltage is reduced
(b) Starting current is reduced
(c) Both (a) and (b)
Ans: c
63. For a D.C. shunt motor which of the following is
incorrect 7
(a) Unsuitable for heavy duty starting
(b) Torque varies as armature current
(c) Torque-armature current is a straight line
(d) Torque is zero for zero armature current
Ans: a

64. For which of the following applications motor has to
start with high acceleration?
(a) Oil expeller
(b) Floor mill
(c) Lifts and hoists
(d) Centrifugal pump
Ans: c
65. Which of the following types of motor enclosure is
safest ?
(a) Totally enclosed
(b) Totally enclosed fan cooled
(c) Open type
(d) Semi closed
Ans: b
66. While selecting motor for an air conditioner which of
the following characteristics is of great importance ?
(a) Type of bearings
(b) Type of enclosure
(c) Noise
(d) Arrangement for power transmis¬sion
(e) None of the above
Ans: c
67. The diameter of the rotor shaft for an electric

motor depends on which of the following ?
(a) r.p.m. only
(b) Horse power only
(c) Horse power and r.p.m.
(d) Horse power, r.p.m. and power factor
Ans: c
68. Which of the following alternatives will be cheaper ?
(a) A 100 H.P. AC. three phase motor
(b) Four motors of 25 H.P. each
(c) Five motors of 20 H.P. each
(d) Ten motors of 10 H.P. each
Ans: a
69. The cost of an induction motor will increase as
(a) horsepower rating increases but r.p.m. decreases
(b) horsepower rating decreases but r.p.m. increases
(c) horsepower rating and operating speed increases
(d) horsepower rating and operating speed decreases
Ans: a
70. In series motor which of the following methods can be
used for changing the flux per pole ?
(a) Tapped field control
(b) Diverter field control
(c) Series-parallel control

Ans: d
Electrolysis Process
1. “The mass of an ion liberated at an electrode is directly proportional
to the quantity of electricity”.
The above statement is associated with
(a) Newton’s law
(b) Faraday’s law of electromagnetic
(c) Faraday’s law of electrolysis
(d) Gauss’s law
Ans: c
2. The charge required to liberate one gram equivalent of any substance is
known as ______ constant
(a) time
(b) Faraday’s
(c) Boltzman
Ans: b
3. During the charging of a lead-acid cell
(a) its voltage increases
(b) it gives out energy
(c) its cathode becomes dark chocolate brown in colour
(d) specific gravity of H2SO4 decreases
Ans: a

4. The capacity of a lead-acid cell does not depend on its
(a) temperature
(b) rate of charge
(c) rate of discharge
(d) quantity of active material
Ans: b
5. During charging the specific gravity of the electrolyte of a lead-acid
battery
(a) increases
(b) decreases
(c) remains the same
(d) becomes zero
Ans: a

Heating Welding

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Question Bank (short Questions)

Subject : UEET (2160907)

Electric Heating and Electric Welding

1. Which of the following is an advantage of heating by

(a) Quicker operation

(b) Higher efficiency

(c) Absence of flue gases

(d) All of the above

2. ________ has the highest value of thermal conductivity.

3. Which of the following heating methods has maximum power factor ?

(a) Arc heating

(b) Dielectric heating

(c) Induction heating

(d) Resistance heating

4 method has leading power factor

 Dr. Subhash Technical Campus- A Jewel of Junagadh 

(b) Dielectric heating

(c) Arc heating

(d) Induction heating

5 is used for heating non-conducting materials.

(a) Eddy current heating

(b) Arc heating

(c) Induction heating

(d) Dielectric heating

6. Which of the following methods of heating is not

dependent on the frequency of supply ?

(a) Induction heating

(b) Dielectric heating

(c) Electric resistance heating

(d) All of the above

7. When a body reflects entire radiation incident on it,

(a) white body

 Dr. Subhash Technical Campus- A Jewel of Junagadh 

(c) black body

(d) transparent body

8. For the transmission of heat from one body to another

(a) temperature of the two bodies must be different

(b) both bodies must be solids

(c) both bodies must be in contact

(d) at least one of the bodies must have some source of

9. Heat transfer by condition will not occur when

(a) bodies are kept in vacuum

(b) bodies are immersed in water

(c) bodies are exposed to thermal radiations

(d) temperatures of the two bodies are identical

10. A perfect black body is one that

(a) transmits all incident radiations

(b) absorbs all incident radiations

(c) reflects all incident radiations

(d) absorbs, reflects and transmits all incident radiations

 Dr. Subhash Technical Campus- A Jewel of Junagadh 

convection and radiation

(a) inside boiler furnaces

(b) during melting of ice

(c) through the surface of the insulted pipe carrying steam

(d) from refrigerator coils to freezer of a refrigerator

12. The process of heat transfer during the reentry of

(c) viscous dissipation