Q 12-06-092JEE MainJEE Main 2022 (26 Jun, Shift 1)Easy
A $10\ \Omega$, $20\ \text{mH}$ coil carrying constant current is connected to a battery of $20\ \text{V}$ through a switch. Now after the switch is opened, the current becomes zero in $100\ \mu\text{s}$. The average emf induced in the coil is ______ V.
Numerical value type. Enter your answer.
Answer: 400
Steady current $I = \dfrac{20}{10} = 2\ \text{A}$.
$$\varepsilon_{\text{avg}} = L\frac{\Delta I}{\Delta t} = 0.02\times\frac{2}{100\times10^{-6}} = 400\ \text{V}$$
Solution by Sreeraj P, M.Sc Physics