Question

A 400 mH coil of negligible resistance is connected to an AC circuit in which an effective current of 6 mA is flowing. Find out the voltage across the coil if the frequency is 1000 Hz.

Answer 1

L = 400 x 10^-3 H; I_eff = 6 x 10^-3 A; f= 1000 Hz 

Inductive reactance, X_L = Lω = L x 2πf = 2 x 3.14 x 1000 x 0.4 = 2512Ω

Voltage across L, V – IX_L = 6 x 10^-3 x 2512 =15.072 V (RMS)