The plates of a parallel plate capacitor have an area of $90\; cm^2$ each and are separated by $2.5\; mm$. The capacitor is charged by connecting it to a $400\; V$ supply.How much electrostatic energy is stored by the capacitor?

Question

$\begin{array}{1 1} 2.55 \times 10^{-6}\;J \\3.55 \times 10^{-6}\;J \\ 7.55 \times 10^{-6}\;J \\ 2 \times 10^{-6}\;J\end{array} $