$A$ capacitor of capacitance $C$ has charge $Q$ and energy stored in it is $W$. If the charge is increased to $3Q$, the energy stored in the capacitor $W'$ will be

The energy stored in a capacitor is in the form of

The plates of a parallel plate capacitor have an area of $90 \,cm^{2}$ each and are separated by $2.5 \,mm$. The capacitor is charged by connecting it to a $400 \,V$ supply.
$(a)$ How much electrostatic energy is stored by the capacitor?
$(b)$ View this energy as stored in the electrostatic field between the plates,and obtain the energy per unit volume $u$. Hence arrive at a relation between $u$ and the magnitude of electric field $E$ between the plates.

$A$ charge of $40\,\mu C$ is given to a capacitor having capacitance $C = 10\,\mu F$. The stored energy in ergs is

Work done by an external agent in separating the plates of a parallel plate capacitor (disconnected from the battery) is:

$A$ parallel plate capacitor has a uniform electric field $\overrightarrow{E}$ in the space between the plates. If the distance between the plates is $d$ and the area of each plate is $A$,the energy stored in the capacitor is: ($\varepsilon_{0} =$ permittivity of free space)