" 20.Derive an expression for the energy stored in a capacitor."

Derive an expression for energy stored in a capacitor,

Answer the following: (a) Describe briefly the process of transferring charge between the two plates of a parallel plate capacitor when connected to a battery. Derive an expression for the energy stored in a capacitor. (b) A parallel plate capacitor is connected to a battery of potential difference V. It is disconnected from battery and then connected to another uncharged capacitor of the same capacitance. Calculate the ratio of the energy stored in the combination to the initial energy on the single capacitor.

The expression for the energy stored in a capacitor is

Derive an expression for the energy stored in a charged capacitor. Express it in different forms.