A 12pF capacitor is connected to a 50V battery. How much electrostatic energy is stored in the capacitor?

We have a 12pF capacitor connected to a 50V battery.

So, the total energy of Capacitor is:

E = 1/2CV²

= 1/2  x 12 x 10^-2  x 50²

&= 1.5 x 10^-8 

The electrostatic energy is stored in the capacitor is =  1.5 x 10^-8 J