A 120-V rms voltage at 60.0 Hz is applied across a capacitor and a 100-Ω resistor. If the impedance of this circuit is 200 Ω, what is the average power of this circuit?
A) 278 W
B) 72.0 W
C) 36.0 W
D) 100 W
E) 200 W

Question

Quizplus · Accepted Answer

The average power in an AC circuit is given by P = V^2 / Z, where V is the rms voltage and Z is the impedance. Here, P = (120^2) / 200 = 72 W. However, the power factor must be considered, which is the ratio of resistance to impedance (100/200 = 0.5). Thus, the average power is 72 W * 0.5 = 36 W.

A 120-V Rms Voltage at 60