Question

An inductor-coil carries a steady-state current of 2.0 A when connected across an ideal battery of emf 4.0 V. If its inductance is 1.0 H, find the time constant of the circuit.

Answer 1

Time Constant is 0.5 s

Explanation:

We know that,

Time constant = $\frac {Self-Inductance (L) of the coil}{Resistance (R) of the circuit}$

Given:

Current in the circuit, i = 2 A

Emf of the battery, E = 4 V

Self-inductance of the coil, L = 1 H

Now,

Resistance of the coil:

R = $\frac {E}{i} = \frac {4}{2} = 2\ \Omega$

Time Constant:

$\tau = \frac {L}{R} = \frac {1}{2}$ = 0.5 s