For a transformer, operating at constant load current, maximum efficiency will occur at______________?

Related Mcqs:

1. The no-load current drawn by transformer is usually what per cent of the full-load current ?

   A. 0.2 to 0.5 per cent
   B. 2 to 5 per cent
   C. 12 to 15 per cent
   D. 20 to 30 per cent

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

   A. value of transformation ratio remains constant
   B. permeability of transformer core remains constant
   C. core flux remains practically constant
   D. primary voltage remains constant
   C. secondary voltage remains constant

3. An ideal transformer will have maximum efficiency at a load such that?

   A. copper loss = iron loss
   B. copper loss iron loss
   D. none of the above

4. A transformer can have zero voltage regulation at______________?

   A. leading power factor
   B. lagging power factor
   C. unity power factor
   D. zero power factor

5. In a step-down transformer, there is a change of 15 A in the load current. This results in change of supply current of_________________?

   A. less than 15 A
   B. more than 15 A
   C. 15 A
   D. none of the above

6. 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

7. 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

8. If a transformer is continuously operated the maximum temperature rise will occur in_______________?

   A. core
   B. windings
   C. tank
   D. any of the above

9. 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

10. The maximum efficiency of a distribution transformer is____________?

    A. at no load
    B. at 50% full load
    C. at 80% full load
    D. at full load