Circuits Containing Resistance?

Question

A 2700ohms resistor and a 1.1-uF capacitor are connected in a series across a generator (60hz, 120V). Determine the power dissipated in the circuit.

Answer 1

X_C = 1/(2π f C) = 1/(2π 60Hz * 1.1 * 10^[-6]) = 2411Ω

Z = √ (R^2 + X_C^2) = √ ([2700Ω]^2 + [2411Ω]^2)  = 3620Ω

I = V_S/Z = 120V/3620Ω = 33.1mA

Now there are three powers in this circuit.  Real power across resistor, reactive power across capacitor and apparent power source delivers.

Real P = I^2 R = (33.1mA)^2 * 2700Ω = 2.97W  --- this is probably your answer

Reactive Q_C = I^2 X_C = (33.1mA)^2 * 2411Ω = 2.65VAR

Apparent S = I^2 Z = (33.1mA)^2 * 3620Ω = 3.98V•A