Correct choice is (a) 37.5 mJ
Best explanation: Given L = 3 mH, i = 5(1 – e^-5000t)
V = L \(\frac{di}{dt} = 3 × 10^{-3} \frac{d}{dt}[5(1-e^{-5000t})] = 75 e^{-5000t}\)
I = i(∞) = 5(1 – e^-∞) = 5 A
E = \(\frac{1}{2}\) LI^2 = 0.5 × 3 × 10^-3 × 5^2 = 37.5 mJ.