$A$ 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?

If the charge on a capacitor is increased by $2 \ C$,the energy stored in it increases by $21 \%$. The original charge on the capacitor is (in $C$)

$A$ capacitor is charged to $200\,V$. It has $0.1\,C$ of charge. When it is discharged,the energy released will be $J$.

$A$ 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:

$A$ $6\,\mu F$ capacitor is charged from $10\,V$ to $20\,V$. The increase in energy will be:

The mean electrical energy density between the plates of a charged air capacitor is (where $q=$ charge on capacitor,$A=$ area of capacitor plate):