A 120-V rms voltage at 60 Hz is applied across an RC circuit. The rms value of the current in the circuit is 0.60 A and it leads the voltage by 60°. What is the value of the resistance in this circuit?
A) 100 Ω
B) 150 Ω
C) 120 Ω
D) 60 Ω
E) 200 Ω

Question

Quizplus · Accepted Answer

The impedance angle of 60° indicates that the circuit is capacitive. The impedance Z can be calculated using Ohm's law: Z = V/I = 120V/0.60A = 200Ω. Since the current leads the voltage by 60°, the resistance R is Z * cos(60°) = 200Ω * 0.5 = 100Ω.

A 120-V Rms Voltage at 60 Hz Is Applied Across