Q 12-06-073JEE MainJEE Main 2023 (15 Apr, Shift 1)Easy
A $12\ \text{V}$ battery connected to a coil of resistance $6\ \Omega$ through a switch, drives a constant current in the circuit. The switch is opened in $1\ \text{ms}$. The emf induced across the coil is $20\ \text{V}$. The inductance of the coil is
Answer: (A) $10\ \text{mH}$
Steady current $I=\dfrac{12}{6}=2\ \text{A}$, which falls to zero in $1\ \text{ms}$.
$$L=\frac{\varepsilon\,\Delta t}{\Delta I}=\frac{20\times10^{-3}}{2}=10\ \text{mH}$$
Solution by Sreeraj P, M.Sc Physics