Transformers Online Test – Multiple Choice Questions and Answers

1. The full-load efficiency of a transformer at 0.85 p.f. lag is 97 per cent. Its efficiency at full load 0.85 bpower factor lead will be

2. If 110 per cent of normal voltage and 110 per cent of normal frequency is applied to a transformer, the percentage change of eddy current losses will be

3. A power transformer is a constant

4. Transformer humming sound is reduced by the

5. The thickness of a 50 Hz transformer lamination is

6. The required thickness of lamination in a transformer decreases when

7. The voltage regulation of a transformer at full-load 0.8 power factor lag is 6 per cent. Its voltage regulation at full-load 0.8 power factor lead will be

8. Oil in transformer is used to

9. If 90 per cent of normal voltage and 90 per cent of normal frequency are applied to a transformer, the per cent charge in hysteresis losses will be

10. Transfer of electrical power from primary to secondary in a transformer takes place