electrical engineering MCQs – Page 260

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 Review each marked answer and report any item that may be outdated or unclear.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
5181. In case of a 4-pole D.C. generator provided with a two layer lap winding with sixteen coils, the pole pitch will be__________________?
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A. 4

B. 16

C. 8

D. 32

5182. 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. all above

C. pulsating magnetic flux

D. oscillating magnetic field

5183. The number of brushes in a commutator depends on______________?
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A. amount of current to be collected

B. speed of armature

C. voltage

D. type of winding

5184. The armature of D.C. generator is laminated to_______________?
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A. provide the bulk

B. reduce the bulk

C. reduce eddy current loss

D. insulate the core

5185. To avoid formation of grooves in the commutator of a D.C. machine?
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A. None

B. the brushes of same polarity should track each other

C. brush position has no effect on the commutator grooving

D. the brushes of opposite polarity should track each other
5186. 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. Compensating field

B. Series field

C. Inter pole field

D. Shunt field
5187. Flashing the field of D.C. generator means:______________?
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A. creating residual magnetism by a D.C. source

B. making the magnetic losses of forces parallel

C. neutralising residual magnetism

D. increasing flux density by adding extra turns of windings on poles

5188. The material for commutator brushes is generally_______________?
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A. carbon

B. mica

C. cast iron

D. copper

5189. If brushes of a D.C. generator are moved in order to bring these brushes in magnetic neutral axis, there will be________________?
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A. cross magnetisation only

B. cross magnetisation as well as magnetisation

C. crossmagnetisation as well as demagnetising

D. demagnetisation only

5190. Which of the following generators will be preferred if they are required to be run in parallel?
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A. Compound generators

B. Series generators

C. Shunt generators

D. None of the above

5191. 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. The field of that generator is weakened

B. That generator takes large share of loads

C. The speed of that generator is increased

D. The direction of that generator is reversed

5192. For both lap and wave windings, there are as many commutator bars as the number of_____________?
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A. armature conductors

B. poles

C. winding elements

D. slots

5193. The purpose of providing dummy coils in a generator is____________?
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A. to enhance flux density

B. to amplify voltage

C. to reduce eddy current losses

D. to provide mechanical balance for the rotor
5194. For a D.C. generator when the number of poles and the number of armature conductors is fixed, then which winding will give the higher e.m.f___________ ?
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A. Lap winding

B. Depends on other features of design

C. Wave winding

D. Either of A. and B. above

5195. In D.C. generators, current to the external circuit from armature is given through_____________?
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A. slip rings

B. commutator

C. none of above

D. solid connection

5196. In a D.C. generator the magnetic neutral axis coincides with the geometrical neutral axis, when_______________?
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A. the generator runs on full load

B. the generator runs on designed speed

C. the generator runs on overload

D. there is no load on|he generator
5197. A 220 V D.C. generator is run at full speed without any excitation. The open circuit voltage will be_____________?
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A. about 2 V

B. zero

C. about 50 V

D. 220 V

5198. 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. slightly less than E

D. 2E
5199. Copper brushes in D.C. machine are used_____________?
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A. where low voltage and high currents are involved

B. where high voltage and small cur-rents are involved

C. in both of the above cases

D. in none of the above cases

5200. The demagnetising component of armature reaction in a D.C. generator___________?
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A. reduces interpoles flux density

B. reduces generator e.m.f.

C. increases armature speed

D. results in sparking trouble