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
Related Mcqs:
- The efficiency of a transformer, under heavy loads, is comparatively low because_______________?
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 - Which of the following is the main advantage of an auto-transformer over a two winding transformer?
A. Hysteresis losses are reduced
B. Saving in winding material
C. Copper losses are negligible
D. Eddy losses are totally eliminated - The changes in volume of transformer cooling oil due to variation of atmospheric temperature during day and night is taken care of by which part of transformer?
A. Conservator
B. Breather
C. Bushings
D. Buchholz relay - In a given transformer for given applied voltage, losses which remain constant irrespective of load changes are______________?
A. friction and windage losses
B. copper losses
C. hysteresis and eddy current losses
D. none of the above - When a given transformer is run at its rated voltage but reduced frequency, its____________?
A. flux density remains unaffected
B. iron losses are reduced
C. core flux density is reduced
D. core flux density is increased - A transformer can have zero voltage regulation at______________?
A. leading power factor
B. lagging power factor
C. unity power factor
D. zero power factor - The voltage transformation ratio of a transformer is equal to the ratio of_______________?
A. primary turns to secondary turns
B. secondary current to primary current
C. secondary induced e.m.f. to primary induced e.m.f
D. secondary terminal voltage to primary applied voltage - If a transformer is switched on to a voltage more than the rated voltage______________?
A. its power factor will deteriorate
B. its power factor will increase
C. its power factor will remain unaffected
D. its power factor will be zero - A good voltage regulation of a transformer means________________?
A good voltage regulation of a transformer means
A. output voltage fluctuation from no load to full load is least
B. output voltage fluctuation with power factor is least
C. difference between primary and secondary voltage is least
D. difference between primary and secondary voltage is maximum - In a given transformer for a given applied voltage, losses which remain constant irrespective of load changes are__________?
A. hysteresis and eddy current losses
B. friction and windage losses
C. copper losses
D. none of the above
