Question

Does the current in an ac circuit lag lead or remain in phase with the voltage of frequency of applied to the circuit when f is equals to f r

Answer 1

The phase difference is <= 90 degrees. It is customary to use the angle by which the voltage leads the current. This leads to a positive phase for inductive circuits since current lags the voltage in an inductive circuit. The phase is negative for a capacitive circuit since the current leads the voltage.