Question

A 50 μF capacitor, when connected in series with a coil having resistance of 40Ω, resonates at 1000 Hz. The circuit current if the applied voltage is 100 V for the resonant circuit is ___________

(a) 2.5 A

(b) 3.5 A

(c) 4.5 A

(d) 0.5 A

The question was posed to me during an interview.

This key question is from Advanced Problems on Resonance topic in section Resonance & Magnetically Coupled Circuit of Network Theory

Answer 1

Right answer is (a) 2.5 A

Easiest explanation: We know that the magnitude of current |I| for a resonating circuit is given by,

| I | = \(\frac{V}{Z} = \frac{V}{R} \)

Given that, R = 40Ω and V = 100 V

∴ | I | = \(\frac{100}{40}\) = 2.5 A.