A $16 \Omega$ wire is bend to form a square loop. A 9 V battery with internal resistance $1 \Omega$ is connected across one of its sides. If a $4 \mu \mathrm{~F}$ capacitor is connected across one of its diagonals, the energy stored by the capacitor will be $\frac{\mathrm{x}}{2} \mu \mathrm{~J}$. where $\mathrm{x}=$ $\_\_\_\_$ .