Question

Calculate the active power in a 543 F capacitor.

(a) 581 W

(b) 897 W

(c) 0 W

(d) 892 W

This question was addressed to me during a job interview.

This key question is from Methods to Reduce the Energy Loss During Starting in section Starting of Electric Drives

Answer 1

Correct option is (c) 0 W

The best I can explain: The capacitor is a linear element. It only absorbs reactive power and stores it in the form of oscillating energy. The voltage and current are 90° in phase in case of the capacitor so the angle between V & I is 90°. P=VIcos90°= 0 W. Current leads the voltage in case of the capacitor.