Question

Discuss energy stored in a capacitance

Answer 1

Capacitors store electric energy. The main expression for the energy stored is

$$E=\frac{1}{2}CV^2.$$

Since

$$C=\frac{Q}{V},$$

the energy can be also expressed as

$$E=\frac{1}{2}QV=\frac{1}{2}\frac{Q^2}{C}.$$

Capacitors can quickly consume electric energy (or charge) and give it out, and this can be considered as a key difference between capacitors and chemical sources of electrical energy.