The potential differences across the resistance, capacitance and inductance are `80 V, 40 V` and `100 V` respectively in an `L-C-R` circuit. The power factor of this circuit is

Options

A. 0.4
B. 0.5
C. 0.8
D. 1

Answer

C

Explanation

Here , `V_R = 80V, V_C = 40V, V_L = 100V`
Power factor , `cos phi = R/Z`
` = (V_R)/(V) = (V_R)/(sqrt(V_R^2 + (V_L - V_C)^2)`
` = (80)/(sqrt((80)^2+ (100 - 40)^2) )= 80/100 = 0.8`