Question

In ac circuit, resistance 5 ohm is connected with capacitor having capacitive reactance 12 ohm. Supply of 260 V is connected to the circuit. Calculate the current in the circuit.

(a) 40 A

(b) 10 A

(c) 20 A

(d) 30 A

This question was posed to me in a job interview.

My question is from Resistance and Capacitance in Series in portion Single Phase Series Circuits of Basic Electrical Engineering

Answer 1

Right choice is (c) 20 A

The explanation is: Z^2=R^2+XC^2 Substituting the values we get Z^2 = 5^2 + 12^2

Z^2 = 169

Z=13 Ω.

I=V/Z = 260/13=20 A.