electrical engineering MCQs – Page 255

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 Review each marked answer and report any item that may be outdated or unclear.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 generation 2. analog electronics 3. solid state switching circuits 4. parallel circuits 5. switchgear and protection 6. op amp circuits 7. transistor audio power amplifiers 8. electrostatics 9. heating and welding 10. multi stage transistor amplifiers 11. passive filters 12. network theorems 13. regulated d c power supply 14. a c fundamentals circuits and circuit theory 15. electromagnetic induction 16. power electronics 17. magnetism and electromagnetism 18. transformers 19. modulation and demodulation 20. d c generators 21. semiconductor theory 22. single phase induction motors 23. semiconductor diode 24. hybrid parameters 25. digital electronics 26. oscillators 27. earthing or grounding 28. single stage transistor amplifiers 29. d c motors 30. transistor biasing 31. amplifiers with negative feedback 32. basic electrical 33. electronic instruments 34. synchronous motors 35. field effect transistors fet 36. magnetic circuit 37. control systems 38. industrial drives 39. power generation 40. series parallel circuits 41. transistor tuned amplifiers 42. electrical engineering materials 43. rectifiers and converters 44. integrated circuits 45. scr silicon controlled rectifiers 46. cables 47. polyphase induction motors 48. measurement and instrumentation 49. transistors 50. electrical machine design 51. electrolysis and storage of batteries 52. electric traction 53. transmission and distribution

5081. A transformer can have regulation closer to zero___________?
0

A. on zero power factor

B. on overload

C. on full-load

D. on leading power factor

5082. The secondary winding of which of the following transformers is always kept closed?
0

A. Potential transformer

B. Step-down transformer

C. Step-up transformer

D. Current transformer

5083. Helical coils can be used on___________?
0

A. low voltage side of high kVA transformers

B. high voltage side of small capacity transformers

C. high frequency transformers

D. high voltage side of high kVA rating transformers

5084. The efficiencies of transformers compared with that of electric motors of the same power are____________?
0

A. much higher

B. much smaller

C. about the same

D. somewhat smaller

E. none of the above

5085. The thickness of laminations used in a transformer is usually____________?
0

A. 4 mm to 5 mm

B. 14 mm to 15 mm

C. 0.4 mm to 0.5 mm

D. 25 mm to 40 mm

5086. The core used in high frequency transformer is usually___________?
0

A. copper core

B. cost iron core

C. air core

D. mild steel core

5087. Noise level test in a transformer is a______________?
0

A. none of the above

B. type test

C. special test

D. routine test

5088. Which of the following is not a part of transformer installation ?
0

A. Exciter

B. Conservator

C. Buchholz relay

D. Breather

5089. Which of the following does not change in a transformer ?
0

A. Voltage

B. All of the above

C. Current

D. Frequency

5090. The efficiency of a transformer will be maximum when_____________?
0

A. hysteresis losses = eddy current losses

B. copper losses = hysteresis losses

C. eddy current losses = copper losses

D. copper losses = iron losses

5091. The hum in a transformer is mainly attributed to______________?
0

A. load changes

B. magnetostriction

C. oil in the transformer

D. mechanical vibrations

5092. Power transformers are designed to have maximum efficiency at___________?
0

A. 50% full load

B. nearly full load

C. 70% full load

D. no load

5093. If the supply frequency to the transformer is increased,the iron loss will__________?
0

A. increase

B. not change

C. any of the above

D. decrease

5094. The value of flux involved m the e.m.f. equation of a transformer is____________?
0

A. maximum value

B. average value

C. instantaneous value

D. r.m.s. value

5095. Which of the following statements regarding an idel single-phase transformer having a turn ratio of 1 : 2 and drawing a current of 10 A from 200 V A.C. supply is incorrect?
0

A. Its secondary voltage is 400 V

B. Its rating is 2 kVA

C. Its secondary current is 5 A

D. It is a step-up transformer

E. Its secondary current is 20 A

5096. If a transformer is switched on to a voltage more than the rated voltage______________?
0

A. its power factor will be zero

B. its power factor will remain unaffected

C. its power factor will deteriorate

D. its power factor will increase

5097. The function of breather in a transformer is___________?
0

A. to cool the transformer oil

B. to arrest flow of moisture when outside air enters the transformer

C. to provide oxygen inside the tank

D. to cool the coils during reduced load

5098. Part of the transformer which is most subject to damage from overheating is_____________?
0

A. copper winding

B. transformer tank

C. winding insulation

D. frame or case

E. iron core

5099. The transformer ratings are usually expressed in terms of______________?
0

A. kW

B. volts

C. amperes

D. kVA

5100. Open circuit test on transformers is conducted to determine____________?
0

A. core losses

B. hysteresis losses

C. copper losses

D. eddy current losses

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