Q 12-06-023NEETJEE MainMedium
An inductor of $2$ H and a $4\ \Omega$ resistor are connected in series to a $12$ V battery at $t = 0$. The time constant and the final current are
Answer: (A) $0.5$ s and $3$ A
Concept. LR circuit: $\tau = \dfrac{L}{R}$ and final current $\dfrac{E}{R}$.
Step 1. Time constant. $\tau = \dfrac24 = 0.5$ s.
Step 2. Final current. $\dfrac{12}{4} = 3$ A.
Answer. $0.5$ s and $3$ A (Option A).
Solution by Sreeraj P, M.Sc Physics