Question

How is the voltage ratio dependent on the frequency?

(a) they are independent of each other

(b) they aid each other

(c) they oppose each other

(d) depends on the setup of the circuit

This question was addressed to me during a job interview.

My question is based upon Reduction of Errors in Potential Transformers in portion Extension of Instrument Ranges of Electrical Measurements

Answer 1

Right choice is (c) they oppose each other

To elaborate: As the voltage ratio changes, the frequency also changes. It depends on the relative value of the core loss component Io as well as the leakage reactance. The effects due to the voltage ratio and the change in frequency oppose each other.