Question

In the circuit given below, the magnitudes of VL and VC are twice that of VK. Calculate the inductance of the coil, given that f = 50.50 Hz.

(a) 6.41 mH

(b) 5.30 mH

(c) 3.18 mH

(d) 2.31 mH

I got this question in an interview for internship.

The question is from Advanced Problems Involving Complex Circuit Diagram topic in division Network Theory and Complex Circuit Diagram of Network Theory

Answer 1

Correct choice is (c) 3.18 mH

Explanation: VL = VC = 2 VR

∴ Q = \(\frac{V_L}{V_R}\)  = 2

But we know, Q = \(\frac{ωL}{R} = \frac{1}{ωCR}\)

∴ 2 = \(\frac{2πf × L}{5}\)

Or, L = 3.18 mH.