When an uncharged capacitor is connected to a battery to charge it fully,

$A$ capacitor of capacity $50\,\mu F$ is charged to $10\;V$. Its energy is equal to:

$A$ capacitor of capacitance $C$ has stored energy $W$ and charge $Q$. If the charge is increased to $2Q$,what will be the new stored energy?

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.

$A$ parallel plate capacitor has a uniform electric field $E$ 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

The work done in placing a charge of $8 \times 10^{-18} \, C$ on a condenser of capacity $100 \, \mu F$ is: