Question

What is the energy stored in the 1.00x10-5 F capacitor of a heart

defibrillator charged to 9.00x103 V?

Answer 1

$$W=\frac{CV^2}{2}$$

$$W=\frac{1.00*10^{-5}*(9.00*10^3)^2}{2}=405\:\rm J$$