A circuit contains resistance and inductance connected in series. The resistor has a true power of 560 W. The inductor has a reactive power of 430 VARs. What is the power factor of this circuit?
A) 79.3%
B) 76.8%
C) 60.9%
D) 83%

Question

Quizplus · Accepted Answer

The power factor is calculated as the true power (P) divided by the apparent power (S), where S is the square root of the sum of the squares of the true power and the reactive power (Q). Thus, power factor = P / sqrt(P^2 + Q^2) = 560 / sqrt(560^2 + 430^2) = 560 / 707.1 = 0.792 or 79.2%, which rounds to 79.3%.

A Circuit Contains Resistance and Inductance Connected in Series