Question

A coil of inductance $8.4mH$ and resistance $4.2\Omega$ is connected to $10V$ battery. The time constant of the circuit is

• A. $2ms$
• B. $0.5ms$
• C. $4ms$
• D. $0.25ms$

Answer 1

The correct option is A $2ms$

Given,

$L=8.4mH$

$R=4.2\Omega$

$V=10V$

Time constant of the circuit is,

$\tau =\frac{L}{R}$

$\tau =\frac{8.4m}{4.2}$

$\tau =2ms$

The correct option is A.