Question

A resistance of 7 ohm is connected in series with an inductance of 31.8mH. The circuit is connected to a 100V 50Hz sinusoidal supply. Calculate the current in the circuit.

(a) 2.2A

(b) 4.2A

(c) 6.2A

(d) 8.2A

I have been asked this question by my college professor while I was bunking the class.

Enquiry is from Resistance and Inductance in Series topic in section Single Phase Series Circuits of Basic Electrical Engineering

Answer 1

Right option is (d) 8.2A

Explanation: XL=2*π*f*L = 10 ohm. Z^2=(R^2+XL^2)

Therefore the total impedance Z = 12.2ohm.

V=IZ, therefore I=V/Z=100/12.2 = 8.2A.