Question

A coil of inductance 8.4 mH and resistance $6\Omega$ is connected to a 12 V battery. The current in the coil is 1.0 A at approximately the time

• A. 500 sec ​
• B. 20 sec ​
• C. 35 milli sec ​
• D. 1 milli sec ​

Answer 1

The correct option is D 1 milli sec ​

Peak current in the circuits $i_0=\frac{12}{6}=2A$
Current decreases from 2A to 1A i.e., becomes half in time
$t=0.693\frac{L}{R}=0.693\times \frac{8.4\times {10}^{-3}}{6}=1$ millisec.