electrical engineering Mcqs
1. economics of power generation2. analog electronics3. solid state switching circuits4. parallel circuits5. switchgear and protection6. op amp circuits7. transistor audio power amplifiers8. electrostatics9. heating and welding10. multi stage transistor amplifiers11. passive filters12. network theorems13. regulated d c power supply14. a c fundamentals circuits and circuit theory15. electromagnetic induction16. power electronics17. magnetism and electromagnetism18. transformers19. modulation and demodulation20. d c generators21. semiconductor theory22. single phase induction motors23. semiconductor diode24. hybrid parameters25. digital electronics26. oscillators27. earthing or grounding28. single stage transistor amplifiers29. d c motors30. transistor biasing31. amplifiers with negative feedback32. basic electrical33. electronic instruments34. synchronous motors35. field effect transistors fet36. magnetic circuit37. control systems38. industrial drives39. power generation40. series parallel circuits41. transistor tuned amplifiers42. electrical engineering materials43. rectifiers and converters44. integrated circuits45. scr silicon controlled rectifiers46. cables47. polyphase induction motors48. measurement and instrumentation49. transistors50. electrical machine design51. electrolysis and storage of batteries52. electric traction53. transmission and distribution
901. A sinusoidal voltage of 5 Hz is applied to the field of a shunt generator. The armature voltage wave will_____________?
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A. will be of 5 Hz

B. will be of v Hz 5

C. will be of 5 xiVHz

D. will be zero

902. With a D.C. generator which of the following regulation is preferred ?
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A. 50% regulation

B. 1% regulation

C. infinite regulation

D. 100% regulation

903. D.C. shunt motors are used for driving____________?
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A. hoists

B. machine tools

C. trains

D. cranes

904. Which of the following motor is preferred for operation in highly explosive atmosphere ?
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A. Battery operated motor

B. Series motor

C. Air motor

D. Shunt motor

905. The purpose of providing dummy coils in a generator is__________________?
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A. to provide mechanical balance for the rotor

B. to reduce eddy current losses

C. to enhance flux density

D. to amplify voltage

906. The number of brushes in a commutator depends on______________?
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A. type of winding

B. amount of current to be collected

C. voltage

D. speed of armature

907. To avoid formation of grooves in the commutator of a D.C. machine?
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A. None

B. brush position has no effect on the commutator grooving

C. the brushes of opposite polarity should track each other

D. the brushes of same polarity should track each other

908. The total losses in a well designed D.C. generator of 10 kW will be nearly______________?
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A. 1000 W

B. 100 W

C. 500 W

D. 1500 W

909. In a D.C. generator the critical resistance can be increased by_____________?
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A. increasing its field resistance

B. decreasing its speed

C. decreasing its field resistance

D. increasing its speed
910. Which D.C. motor has got maximum self loading property?
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A. Shunt motor

B. Differentially compounded motor

C. Series motor

D. Cumulatively compounded motor

911. In a D.C. generator all of the following could be the effects of iron losses except___________?
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A. Rise in temperature of ventilating air

B. Excessive heating of core

C. Increase in terminal voltage

D. Loss of efficiency

912. Which motor should not be started on no-load ?
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A. Differentially compounded motor

B. Shunt motor

C. Cumulatively compounded motor

D. Series motor
913. The commutator segments are connected to the armature conductors by means of___________?
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A. copper lugs

B. insulation pads

C. resistance wires

D. brazing

914. The torque of an induction motor is___________?
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A. inversely proportional to slip

B. none of the above

C. directly proportional to slip

D. proportional to the square of the slip

915. As -the load is increased the speed of D.C. shunt motor will____________?
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A. increase proportionately

B. remains unchanged

C. reduce slightly

D. increase slightly

916. The function of pole shoes in the case of D.C. machine is______________?
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A. to reduce the reluctance of the magnetic path

B. to support the field coil

C. to spread out the flux to achieve uniform flux density

D. to discharge all the above functions
917. If residual magnetism is present in a D.C. generator, the induced e.m.f. at zero speed will be____________?
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A. high

B. the same as rated voltage

C. small

D. zero
918. The main disadvantage of the Ward-Leonard control method is______________?
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A. high maintenance cost

B. high initial cost

C. all of the above

D. low efficiency at Hght loads

919. In a differentially compounded D.C. motor, if shunt field suddenly opens____________?
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A. the motor will work as series motor and run at slow speed in the same direction

B. the motor will work as series motor and run at high speed in the same direction

C. the motor will first stop and then run in opposite direction as series motor

D. the motor will not work and come to stop

920. Two generators are running in parallel. One of the generators may run as motor for which of the following reasons ?
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A. That generator takes large share of loads

B. The field of that generator is weakened

C. The speed of that generator is increased

D. The direction of that generator is reversed

921. If the supply voltage for a D.C. motor is increased, which of the following will decrease ?
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A. Full-load current

B. Operating speed

C. All of the above

D. Starting torque

922. In D.C. generators the polarity of the interpoles_____________?
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A. is the same as that of the immediately preceding pole

B. is opposite to that of the main pole ahead

C. is the same as that of the main pole ahead

D. is neutral as these poles do not play part in generating e.m.f.

923. With the increase in temperature, the speed of DC series motor______________?
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A. increases

B. decreases

C. remain same

D. none of the above

924. Which method of braking is generally used in elevators ?
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A. Plugging

B. None of the above

C. Rheostatic braking

D. Regenerative braking

925. To achieve sparkless commutation brushes of a D.C. generator are rockedm ahead so as to bring them?
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A. in magnetic neutral axis

B. none

C. just behind the magnetic neutral axis

D. just ahead of magnetic neutral axis
926. In which of the following applications D.C. series motor is invariably tried?
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A. Drive for a water pump

B. Starter for a car

C. Fan motor

D. Motor operation in A.C. or D.C

927. Which of the following motor has the poorest speed regulation ?
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A. Differential compound motor

B. Series motor

C. Cumulative compound motor

D. Shunt motor

928. In D.C. generators, current to the external circuit from armature is given through_____________?
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A. solid connection

B. none of above

C. slip rings

D. commutator
929. In case of D.C. machines, mechanical losses are primary function of____________?
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A. current

B. none of above

C. speed

D. voltage

930. D.C. motor is to a drive a load which is almost nil for certain part of the load cycle and peak value for short duration. We will select this______________?
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A. compound motor

B. any of the above

C. shunt motor

D. series motor

931. In lap winding, the number of brushes is always_____________?
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A. two

B. same as the number of poles

C. double the number of poles

D. half the number of poles

932. The power mentioned on the name plate of an electric motor indicates____________?
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A. the gross power

B. the output power available at the shaft

C. the power drawn in kW

D. the power drawn in kVA

933. Which of the following motors one will choose to drive the rotary compressor ?
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A. Synchronous motor

B. D.C. shunt motor

C. Universal motor

D. D.C. series motor

934. Which of the following motors is most suitable for signalling devices and many kinds of timers ?
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A. D.C. series motor

B. D.C. shunt motor

C. Induction motor

D. Reluctance motor
935. Hopkinsons test on D.C. machines is conducted at_______________?
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A. no-load

B. full-load

C. part load

D. overload

936. When the armature of a D.C. motor rotates, e.m.f. induced is___________?
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A. none of the above

B. mutually induced e.m.f.

C. self-induced e.m.f.

D. back e.m.f
937. Which of the following D.C. generators will be in a position to build up without any residual magnetism in the poles?
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A. Series generator

B. Shunt generator

C. None of the above

D. Compound generator

938. Torque developed by a D.C. motor depends upon_____________?
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A. magnetic field

B. current flow through the conductors

C. all above factors

D. radius of armature

E. number of conductors

F. active length of the conductor

939. Which of the following steps is likely to result in reduction of hysteresis loss in a D.C. generator ?
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A. Providing laminations in stator

B. Using non-magnetic material for frame

C. Providing laminations in armature core

D. Using material of low hysteresis co-efficient for armature core material
940. In D.C. motor which of the following can sustain the maximum temperature rise?
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A. Armature winding

B. Commutator

C. Field winding

D. Slip rings

941. The shape of the torque/slip curve of induction motor is__________?
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A. rectangular parabola

B. parabola

C. hyperbola

D. straigth line

942. Slip ring motor is recommended where____________?
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A. high starting torque is needed

B. frequent starting, stopping and reversing is required

C. speed control is required

D. all above features are required
943. In a ceilingfan employing capacitor run motor____________?
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A. secondary winding surrounds the primary winding

B. primary winding surrounds the secondary winding

C. both are usual arrangements

D. none of the above

944. The wattage rating for a ceiling fan motor will be in the range_________?
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A. 50 to 150 W

B. 10 to 20 W

C. 250 to 500 W

D. 200 to 250 W

945. When a D.C. series motor is connected to A.C. supply, the power factor will be low because of____________?
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A. induced current in rotor due to variations of flux

B. fine copper wire winding

C. none of the above

D. high inductance of field and armature circuits
946. A 3-phase induction motor stator delta connected, is carrying full load and one of its fuses blows out. Then the motor_______________?
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A. will continue running burning its one phase

B. will stop and carry heavy current causing permanent damage to its winding

C. will continue running without any harm to the winding

D. will continue running burning its two phases

947. Which of the following single-phase motors has relatively poor starting torque ?
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A. Capacitor motor

B. All single phase motors have zero starting torque

C. Universal motor

D. Repulsion motor

948. The power scale of circle diagram of an induction motor can be found from__________?
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A. short-circuit test only

B. no-load test only

C. noue of the above

D. stator resistance test

949. A capacitor-start single phase induction motor is switched on to supply with its capacitor replaced by an inductor of equivalent reactance value. It will______________?
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A. start and then stop

B. start and run at rated speed

C. start and run slowly

D. not start at all
950. Low voltage at motor terminals is due to____________?
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A. inadequate motor wiring

B. none of the above

C. poorely regulated power supply

D. any one of the above