Energy is stored in what form in a capacitor?

If potential difference across a capacitor is changed from $15 \ V$ to $30 \ V,$ work done is $W.$ The work done,when potential difference is changed from $30 \ V$ to $60 \ V,$ will be $.......W$

If the charge on a capacitor is increased by $2 \ C$,the energy stored in it increases by $44 \%$. The original charge on the capacitor is (in $C$):

Energy per unit volume for a capacitor having area $A$ and separation $d$ kept at potential difference $V$ is given by

Consider a parallel plate capacitor of area $A$ (of each plate) and separation $d$ between the plates. If $E$ is the electric field and $\varepsilon_0$ is the permittivity of free space between the plates,then the potential energy stored in the capacitor is $:-$

$A$ 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 $[\varepsilon_0 = \text{permittivity of free space}]$