A coil is connected in series with a $8\mathrm{.}02$ kQ resistor. An ideal $68\mathrm{.}2$ V battery is applied across the two devices, and the current reaches a

value of $2\mathrm{.}70$ mA after $4\mathrm{.}29$ ms$.($a$)$ Find the inductance of the coil. $($b$)$ How much energy is stored in the coil at this same moment?