Q.

A 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 'A', the energy stored in the capacitor is (ε0 = permittivity of free space)             [2021]

1 E2Adε0  
2 12ε0E2  
3 ε0EAd  
4 12ε0E2Ad  

Ans.

(4)

The capacitance of a parallel plate capacitor of plate area A and separation d is given by

              C=ε0Ad

The potential is given by V=Ed

Where E is electric field.

Energy, U=12CV2=12×ε0Ad×E2d2  ;  U=12ε0E2Ad