JEE Main 2020 Physics question
An emf of 20 V is applied at time t = 0 to a circuit containing in series 10 mH inductor and 5 resistor. The ratio of the currents at time and at t = 40 s is close to: (Take )
Answer: (B)
Solution
With L/R = 2 ms, e^(−Rt/L) is negligible at t = 40 s, so the ratio is ≈ 1; the nearest option is 1.06 (as in the paper's key).