A parallel plate capacitor has a uniform electric field `vec(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

Options

A. `epsilon_0EAd`
B. `1/2epsilon_0E^2Ad`
C. `(E^2 Ad)/(epsilon_0)`
D. `1/2epsilon_0E^2`

Answer

B

Explanation

Energy density `=1/2 epsilon_0E^2`
`= U/("volume") =1/2 epsilon_0E^2`
`U/(Ad) =1/2 epsilon_0E^2`
`U=1/2 epsilon_0 E^2 Ad`