## College Physics (4th Edition)

(a) $Q = 1.8\times 10^{-8}~C$ (b) $U = 1.35\times 10^{-6}~J$
(a) We can find the charge on the capacitor: $Q = C~\Delta V$ $Q = (\frac{\epsilon_0~A}{d})~\Delta V$ $Q = (\frac{(8.854\times 10^{-12}~F/m)~(0.10~m)^2}{0.75\times 10^{-3}~m})~(150~V)$ $Q = 1.8\times 10^{-8}~C$ (b) We can find the energy stored in the capacitor: $U = \frac{1}{2}~Q~V$ $U = \frac{1}{2}~(1.8\times 10^{-8}~C)(150~V)$ $U = 1.35\times 10^{-6}~J$