electrical engineering MCQs – Page 251

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 Review each marked answer and report any item that may be outdated or unclear.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

5001. The voltage transformation ratio of a transformer is equal to the ratio of_______________?
0

A. secondary terminal voltage to primary applied voltage

B. secondary induced e.m.f. to primary induced e.m.f

C. secondary current to primary current

D. primary turns to secondary turns

5002. Reduction in core losses and increase in permeability are obtained with transformer employing__________?
0

A. core built-up of laminations of cold rolled grain oriented steel

B. core built-up of laminations of hot rolled sheet

C. none of the above

D. either of the above

5003. The main reason for generation of harmonics in a transformer could be_______________?
0

A. poor insulation

B. fluctuating load

C. saturation of core

D. mechanical vibrations

5004. Which of the following acts as a protection against high voltage surges due to lightning and switching ?
0

A. Horn gaps

B. Thermal overload relays

C. Conservator

D. Breather

5005. In the transformer the function of a conservator is to_______________?
0

A. none of the above

B. provide fresh air for cooling the transformer

C. protect the transformer from damage when oil expends due to heating

D. supply cooling oil to transformer in time of need

5006. The efficiency of a transformer, under heavy loads, is comparatively low because_______________?
0

A. copper loss becomes high in proportion to the output

B. iron loss is increased considerably

C. voltage drop both in primary and secondary becomes large

D. secondary output is much less as compared to primary input

5007. Star/star transformers work satisfactorily when________________?
0

A. none of the above

B. load is balanced only

C. on balanced as well as unbalanced loads

D. load is unbalanced only

5008. The use of higher flux density in the transformer design____________?
0

A. reduces iron losses

B. reduces copper losses

C. reduces weight per kVA

D. increases part load efficiency

5009. No-load current in a transformer________________?
0

A. leads the voltage by about 75

B. leads the voltage by about 15

C. lags behind the voltage by about 15

D. lags behind the voltage by about 75

5010. The purpose of providing iron core in a step-up transformer is?
0

A. to provide coupling between primary and secondary

B. to decrease the magnitude of mag-netizing current

C. to increase the magnitude of mutual flux

D. to provide all above features

5011. Which of the following is not a routine test on transformers ?
0

A. Impedance test

B. Polarity test

C. Core insulation voltage test

D. Radio interference test

5012. Hysteresis loss in a transformer varies as CBmax = maximum flux density) ?
0

A. Bmax1-6

B. Bmax

C. Bmax1-83

D. B max

5013. The transformer laminations are insulated from each other by____________?
0

A. mica strip

B. thin coat of varnish

C. paper

D. any of the above

5014. Two transformers operating in parallel will share the load depending upon their____________?
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A. per unit impedance

B. efficiencies

C. ratings

D. leakage reactance

5015. An ideal transformer has infinite values of primary and secondary inductances. The statement is______________?
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A. false

B. TRUE

5016. In a given transformer for a given applied voltage, losses which remain constant irrespective of load changes are__________?
0

A. hysteresis and eddy current losses

B. friction and windage losses

C. copper losses

D. none of the above

5017. A no-load test is performed on a transformer to determine_______________?
0

A. magnetising current and loss

B. core loss

C. efficiency

D. copper loss

E. magnetising current

5018. A transformer can have zero voltage regulation at______________?
0

A. leading power factor

B. lagging power factor

C. unity power factor

D. zero power factor

5019. Greater the secondary leakage flux____________?
0

A. less will be the primary terminal voltage

B. less will be the secondary induced e.m.f.

C. less will be the primary induced e.m.f.

D. none of the above

5020. The efficiency of two identical transformers under load conditions can be determined by_______________?
0

A. open circuit test

B. any of the above

C. back-to-back test

D. short-circuit test

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