An inductor of 10 mH is connected to a 20 V battery through a resistor of 10 k Ω and a switch. After a long time, when maximum current is set up in…

An inductor of $\displaystyle 10$ mH is connected to a $\displaystyle 20$ V battery through a resistor of $\displaystyle 10 \mathrm{k} \Omega$ and a switch. After a long time, when maximum current is set up in the circuit, the current is switched off. The current in the circuit after $\displaystyle 1 \mu \mathrm{~s}$ is $\displaystyle \frac{x}{100} \mathrm{~mA}$. Then $\displaystyle x$ is equal to \_\_\_\_. $\displaystyle \left(\right.$ Take $\displaystyle \left.\mathrm{e}^{-1}=0.37\right)$