Question

How much electrical potential energy is stored in a capacitor that has 4.0 x10^10 C of charge on each plate and a potential difference across the platesof 20.0 V?

Answer 1

The electric potential energy is given by:

$PE_e=\frac{1}{2}QV$

plugging the values given we have:

$\begin{gathered} PE_e=\frac{1}{2}(4\times10^{-10})(20) \\ PE_e=4\times10^{-9} \end{gathered}$

Therefore the answer is A.