A parallel plate air capacitor has a uniform electric field $E$ in the space between the plates. Area of…
A parallel plate air capacitor has a uniform electric field $E$ in the space between the plates. Area of each plate is $A$ and the distance between the plates is $d$. The energy stored in the capacitor is $\left[\varepsilon_0=\right.$ permittivity of free space $]$
$2 \varepsilon_0 E A d$
$\frac{\varepsilon_0 E^2}{2 A d}$
$\frac{1}{2} \varepsilon_0 E^2 A d$
$\frac{E^2 A d}{2 \varepsilon_0}$
Solution
The energy stored in the capacitor is
$U=\frac{1}{2} C V^2=\frac{1}{2}\left(\frac{\varepsilon_0 A}{d}\right)(E d)^2$