A certain ac signal at 60 Hz is applied across a 40-mH inductor and a 200-Ω resistor. What is the power factor of this circuit?
A) 0.249
B) 0.497
C) 0.697
D) 0.997
E) None of the other answers is correct.

Question

Quizplus · Accepted Answer

The power factor is the cosine of the phase angle, which is determined by the impedance of the circuit. The inductive reactance (X_L) is 2πfL = 2π(60)(0.04) = 15.08 Ω. The impedance (Z) is √(R^2 + X_L^2) = √(200^2 + 15.08^2) ≈ 200.57 Ω. The power factor is R/Z = 200/200.57 ≈ 0.997.

A Certain Ac Signal at 60 Hz Is Applied Across