TOP Transformers Multiple choice Questions and Answers pdf

11.   The efficiency of a transformer will be maximum when
(a) copper losses = hysteresis losses
(b) hysteresis losses = eddy current losses
(c) eddy current losses = copper losses
(d) copper losses = iron losses
Ans: d

12.    No-load current in a transformer
(a) lags behind the voltage by about 75°
(b) leads the voltage by about 75°
(c) lags behind the voltage by about 15°
(d) leads the voltage by about 15°
Ans: a

13.    The purpose of providing an iron core in a transformer is to
(a) provide support to windings
(b) reduce hysteresis loss
(c) decrease the reluctance of the magnetic path
(d) reduce eddy current losses
Ans: c

14.    Which of the following is not a part of transformer installation ?
(a) Conservator   
(b) Breather
(c) Buchholz relay
(d) Exciter
Ans: d

15.    While conducting short-circuit test on a transformer the following side is short circuited
(a)    High voltage side
(b)    Low voltage side
(c)    Primary side  
(d)     Secondary side
Ans: b

16.    In the transformer following winding has got more cross-sectional area
(a)    Low voltage winding
(b)    High voltage winding
(c)    Primary winding
(d)     Secondary winding
Ans: a

17.   A transformer transforms
(a) voltage 
(b) current
(c) power 
(d) frequency
Ans: c

18.    A transformer cannot raise or lower the voltage of a D.C. supply because
(a) there is no need to change the D.C. voltage
(b) a D.C. circuit has more losses
(c) Faraday's laws of electromagnetic induction are not valid since the rate of change of flux is zero
(d) none of the above
Ans: c

19.    Primary winding of a transformer
(a)    is always a low voltage winding
(b)    is always a high voltage winding
(c)    could either be a low voltage or high voltage winding
(d)     none of the above
Ans: c

20.    Which winding in a transformer has more number of turns ?
(a)     Low voltage winding
(b)     High voltage winding
(c)    Primary winding
(d)    Secondary winding
Ans: b

Read More Questions:
Transformers MCQs Part1
Transformers MCQs Part2

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