The core used in high frequency transformer is usually___________?

If the percentage impedances of the two transformers working in parallel are different, then______________________?

A. transformers will be overheated
B. power factors of both the transformers will be same
C. parallel operation will be not possible
D. parallel operation will still be possible, but the power factors at which the two transformers operate will be different from the power factor of the common load

The function of conservator in a transformer is___________________?

A. to project against’internal fault
B. to reduce copper as well as core losses
C. to cool the transformer oil
D. to take care of the expansion and contraction of transformer oil due to variation of temperature of sur-roundings

The secondary of a current transformer is always short-circuited under operating conditions because it____________________?

A. avoids core saturation and high voltage induction
B. is safe to human beings
C. protects the primary circuit
D. none of the above

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°

The full-load copper loss of a trans¬former is 1600 W. At half-load, the copper loss will be___________?

A. 6400 W
B. 1600 W
C. 800 W
D. 400 W

A Transformer transforms____________?

A. voltage
B. current
C. current and voltage
D. power