Electromagnetic Induction

Inductance of a coil with $10^4$ turns is 10 mH and it is connected to a dc source of 10 V with internal resistance of $10 \Omega$. The energy density in the inductor when the current reaches $\left(\frac{1}{e}\right)$ of its maximum value is $\alpha \pi \times \frac{1}{e^2} \mathrm{~J} / \mathrm{m}^3$. The value of $\alpha$ is

$\_\_\_\_$ .

\(\left(\mu_0=4 \pi \times 10^{-7} \mathrm{Tm} / \mathrm{A}\right) .\)