transformers MCQs – Page 3

Practise focused transformers questions with marked answers for exam preparation and subject revision.

transformers Mcqs

41. The transformer laminations are insulated from each other by____________?
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A. mica strip

B. thin coat of varnish

C. paper

D. any of the above

42. 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

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

B. TRUE

44. In a given transformer for a given applied voltage, losses which remain constant irrespective of load changes are__________?
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A. hysteresis and eddy current losses

B. friction and windage losses

C. copper losses

D. none of the above

45. A no-load test is performed on a transformer to determine_______________?
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A. magnetising current and loss

B. core loss

C. efficiency

D. copper loss

E. magnetising current

46. A transformer can have zero voltage regulation at______________?
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A. leading power factor

B. lagging power factor

C. unity power factor

D. zero power factor

47. Greater the secondary leakage flux____________?
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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

48. The efficiency of two identical transformers under load conditions can be determined by_______________?
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A. open circuit test

B. any of the above

C. back-to-back test

D. short-circuit test

49. Which of the following is the main advantage of an auto-transformer over a two winding transformer?
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A. Saving in winding material

B. Eddy losses are totally eliminated

C. Copper losses are negligible

D. Hysteresis losses are reduced

50. Which of the following properties is not necessarily desirable for the material for transformer core ?
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A. High thermal conductivity

B. Low hysteresis loss

C. Adequate mechanical strength

D. High permeability

51. Which winding in a transformer has more number of turns ?
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A. High voltage winding

B. Low voltage winding

C. Secondary winding

D. Primary winding

52. If a transformer is continuously operated the maximum temperature rise will occur in_______________?
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A. windings

B. any of the above

C. core

D. tank

53. For given applied voltage, with the increase in frequency of the applied voltage?
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A. eddy current loss will remain unchanged

B. eddy current loss will decrease

C. eddy current loss will increase

D. none of the above

54. The transformer oil should have _______ volatility and _______ viscosity?
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A. low,high

B. high,high

C. low,low

D. high,low

55. In an actual transformer the iron loss remains practically constant from no load to full load because:____________?
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A. secondary voltage remains constant

B. core flux remains practically constant

C. permeability of transformer core remains constant

D. value of transformation ratio remains constant

E. primary voltage remains constant

56. The degree of mechanical vibrations produced by the laminations of a transformer depends on____________?
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A. gauge of laminations

B. all of the above

C. size of laminations

D. tightness of clamping

57. Which of the following insulating materials can withstand the highest temperature safely ?
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A. Glass fibre

B. Asbestos

C. Mica

D. Cellulose

58. The dielectric strength of transformer oil is expected to be______________?
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A. 33 kV

B. lkV

C. 100 kV

D. 330 kV

59. In a transformer routine efficiency depends upon_____________?
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A. supply frequency

B. load current

C. power factor of load

D. both B. and (c)

60. While conducting short-circuit test on a transformer the following side is short circuited?
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A. Primary side

B. Low voltage side

C. Secondary side

D. High voltage side

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