Question

An emf of 20 V is applied at time t = 0 to a circuit containing in series 10 mH inductor and 5 Ω resistor. The ratio of the currents at time t = ∞ and at t = 40 s is close to : (Take e² = 7.389)

(1) 1.06

(2) 1.15

(3) 1.46

(4) 0.84

Answer 1

Answer is (1) 1.06

Answer 2

Answer is (1) 1.06

i = i₀ (1 – e^–Rt/L)