$A$ parallel plate air capacitor has a uniform electric field $E$ in the space between the plates. The area of each plate is $A$ and the distance between the plates is $d$. The energy stored in the capacitor is $[\varepsilon_0 = \text{permittivity of free space}]$

• A
  $2 \varepsilon_0 E A d$
• B
  $\frac{\varepsilon_0 E^2}{2 A d}$
• C
  $\frac{1}{2} \varepsilon_0 E^2 A d$
• D
  $\frac{E^2 A d}{2 \varepsilon_0}$