Question

In the circuit given below, M = 20. The resonant frequency is _______________

(a) 4.1 Hz

(b) 41 Hz

(c) 0.41 Hz

(d) 0.041 Hz

This question was addressed to me during an online exam.

The doubt is from Advanced Problems Involving Complex Circuit Diagram in portion Network Theory and Complex Circuit Diagram of Network Theory

Answer 1

The correct option is (d) 0.041 Hz

Best explanation: IEQ = L1 + L2 + 2M

LEQ = 10 + 20 + 2 × \(\frac{1}{20}\) = 30.1 H

∴ FO = \(\frac{1}{2π\sqrt{LC}}\)

= \(\frac{1}{2π\sqrt{30.1 × 0.5}}\)

= 0.041 Hz.