The mean electric energy density between the plates of a charged capacitor is (here $q$ = charge on the capacitor and $A$ = area of the capacitor plate).

$A$ battery does $200 \, J$ of work in charging a capacitor. The energy stored in the capacitor is ......... $J$.

Two capacitors,one of capacity $\frac{C}{2}$ and the other of capacity $C$,are connected to a battery of voltage $V$ as shown. The work done in charging both the capacitors fully is

If the charge on a body is increased by $2 \ C$,the energy stored in it increases by $21 \%$. The original charge on the body in coulomb is:

$A$ parallel plate capacitor having plate area $A$ and separation $d$ is charged to a potential difference $V$. The charging battery is disconnected and the plates are pulled apart to four times the initial separation. The work required to increase the distance between the plates is ($\epsilon_0 =$ permittivity of free space).

Three plates $A, B, C$ each of area $50 \, cm^2$ have a separation of $3 \, mm$ between $A$ and $B$ and $3 \, mm$ between $B$ and $C$. The energy stored when the plates are fully charged is (as shown in the figure):