RLC Circuits and Resonance - Technical MCQs

Q1:

What is the power factor?

A 0.279

B 0.479

C 0.679

D 0.879

ANS:A - 0.279

For true power P, I used V^2/R /= 497^2/4k = 61.75 W.
Apparent Power, I used V^2/Z = 497^2/3516 = 70.23 VA.
Pf = P/S (real power/apparent power) = 61.75/70.23 = 0.879.