Q 12-06-032JEE MainJEE Main 2026 (6 Apr, Shift 1)Medium
An inductor of inductance $10$ mH having resistance of $100\ \Omega$ is connected to battery of E.M.F. $1.0$ V through a switch as shown in the figure below. After switch is closed, the ratio of instantaneous voltages across the inductor when the current passing through it is $2$ mA and $4$ mA is ______.
Answer: (A) $4/3$
Concept. In the growing LR circuit the voltage across the ideal inductance is $V_L=E-iR$.
Step 1. At 2 mA. $1-0.002\times100=0.8$ V.
Step 2. At 4 mA. $1-0.4=0.6$ V.
Step 3. Ratio. $\dfrac{0.8}{0.6}=\dfrac43$.
Answer. Option A.
Solution by Sreeraj P, M.Sc Physics
