A series RLC circuit with a 140ohm resistor dissipates 76W w

A series RLC circuit with a 140ohm resistor dissipates 76W when attached to a 120V/60Hz power line. What is the power factor? Express your answer using two significant figures.

Solution

power factor = cos(phi) = power/(VI) = 76/(120

I = V/R =

I = V/R = 120/140 = 0.8571

power factor = cos(phi) = power/(VI) = 76/(120*0.8571) = 0.73892