A series LCR circuit is connected to an a.c source whose frequency is less than the resonant frequency of the circuit. Which one will you increase to improve the power factor of the circuit L or C. Justify your answer.

For ideal power factor, the angle should be minimized.To do this, we need to increase the inductive impedance so that the voltage angle theta slowly reducesand becomes zero in the ideal case.Hence, the answer to your question isIncrease the Inductive inpedance.