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

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.