electrical engineering MCQs – Page 45

Practise multiple-choice questions from electrical engineering for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

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
881. Eddy currents are induced in the pole shoes of a D.C. machine due to______________?
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A. relative rotation between field and armature

B. oscillating magnetic field

C. pulsating magnetic flux

D. all above

882. In case of D.C. shunt motors the speed is dependent on back e.m.f. only because____________?
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A. back e.m.f. is equal to armature drop

B. flux is proportional to armature current

C. flux is practically constant in D:C. shunt motors

D. armature drop is negligible

883. In D.C. generators, the cause of rapid brush wear may be___________?
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A. severe sparking

B. rough commutator surface

C. imperfect contact

D. any of the above
884. Which of the following method of speed control of D.C. machine will offer minimum efficiency ?
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A. Field control method

B. Armature control method

C. Voltage control method

D. All above methods

885. Which of the following loss in a D.C. generator varies significantly with the load current ?
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A. Armature copper loss

B. None of the above

C. Windage loss

D. Field copper loss

886. The e.m.f. generated by a shunt wound D.C. generator isE. Now while pole flux remains constant, if the speed of the generator is doubled, the e.m.f. generated will be_______________?
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A. E/2

B. E

C. 2E

D. slightly less than E

887. The following constitute short-circuit in the armature winding.
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A. All of the above

B. Two of more turns of the same coil getting grounded

C. Insulation failure between two commutator bars

D. Insulation failure between two turns of a coil

888. A D.C. generator can be considered as____________?
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A. rectifier

B. primemover

C. rotating amplifier

D. power pump

889. Two generators A and B have 6-poles each. Generator A has wave wound armature while generator B has lap wound armature. The ratio of the induced e.m.f. is generator A and B will be_______________?
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A. 3:02

B. 2:03

C. 3 : 1

D. 1:03

890. Starters are used with D.C. motors because______________?
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A. these motors are not self-starting

B. these motors have high starting torque

C. back e.m.f. of these motors is zero initially

D. to restrict armature current as there is no back e.m.f. while starting
891. Regenerative method of braking is based on that___________?
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A. back e.m.f. is less than the applied voltage

B. none of the above

C. back e.m.f. is equal to the applied voltage

D. back e.m.f. of rotor is more than the applied voltage

892. Following energized winding of a D.C. machine should not be opened as it would produce high inductive voltage which may be dangerous to personnel and may cause its own insulation failure.
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A. Shunt field

B. Compensating field

C. Inter pole field

D. Series field

893. Speed control by Ward Leonard method gives uniform speed variation_____________?
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A. in one direction

B. in both directions

C. below normal speed only

D. above normal speed only

894. If the terminals of armature of D.C. motor are interchanged, this action will offer following kind of braking?
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A. dynamic braking

B. any of the above

C. none of the above

D. regenerative

E. plugging
895. A shunt generator running at 1000 r.p.m. has generated e.m.f. as 200 V. If the speed increases to 1200 r.p.m., the generated e.m.f. will be nearly_______________?
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A. 240 V

B. 150 V

C. 290 V

D. 175 V

896. Lap winding is composed of_____________?
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A. that even number which is exact multiple of poles + 2

B. that even number which is exact multiple of poles

C. any odd number of conductors

D. any even number of conductors
897. The purpose of providing dummy coils in a generator is____________?
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A. to enhance flux density

B. to reduce eddy current losses

C. to provide mechanical balance for the rotor

D. to amplify voltage

898. For which of the following applications a D.C. motor is preferred over an A.C. motor ?
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A. Low speed operation

B. High speed operation

C. Variable speed operation

D. Fixed speed operation

899. For a D.C. machines laboratory following type of D.C. supply will be suitable___________?
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A. mercury are rectifier

B. induction motor D.C. generator set

C. synchronous motor D.C. generator set

D. rotary converter

900. In variable speed motor___________?
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A. a stronger commutating field is needed at low speed than at high speed

B. none of the above is correct

C. a weaker commutating field is needed at low speed than at high speed

D. same commutating field is needed at low speed than at high speed