Question

An air-filled parallel plate capacitor has a uniform electric field `overset(->)("E")` in the space between the plates. If the distance between the plates is 'd' and the area of each plate is 'A', the energy stored in the capacitor is ______ 
(∈₀ = permittivity of free space)

Options

• `(E^2 (Ad))/∈_0`

• `1/2∈_0 E^2`

• `∈_0E  Ad`

• `1/2∈_0 E^2 Ad`

Answer 1

An air-filled parallel plate capacitor has a uniform electric field 'E' in the space between the plates. If the distance between the plates is 'd' and the area of each plate is 'A', the energy stored in the capacitor is `underline(1/2∈_0 E^2 Ad)`.

Explanation:

Energy per unit volume in an electric field is

U = `1/2∈_0 E^2`

The volume of the space between the plates is = Ad

∴ Energy stored in the electric field = `1/2∈_0 E^2 Ad`