A coil of inductance $1 H$ and resistance $10 \Omega$ is connected to a resistance-less battery of EMF $50 \mathrm{~V}$ at time $t=0 .$ The ratio of rate at which magnetic energy is stored in the coil to the rate at which energy is supplied by the battery at $t=0.1 \mathrm{~s} .$ is $x \times 10^{-2}$. Find the value of $x$. (Given $\left.\frac{1}{e}=0.37\right)$