An alternating voltage e=200s in100t is applied to a series combination of R= 30Ω and an inductor of 400 mH. The power factor of the circuit is

Options

(a) 0.01
(b) 0.05
(c) 0.042
(d) 0.6

Correct Answer:

0.6

Explanation:

Xʟ = Lω = 0.4 × 100 = 40
R = 30 Ω
.·. Power factor, cos ɸ = R / √(R² × Xʟ²) = 30 / √(R² × Xʟ²) = 30 / √(30² × 40²) = 0.6