# A parallel plate condenser have a uniform electric field $E(V/m)$ in the space between the plates. If the distance between the plates is $d(m)$ and area of each plate is $A(m^2)$ the energy (joules) stored in the condenser is :
( A ) $E^2 Ad/\epsilon _0$
( B ) $\frac{1}{2} \epsilon _0 E^2$
( C ) $\epsilon _0 EAd$
( D ) $\frac{1}{2} \epsilon _0 E^2 Ad$