The energy required to charge a capacitor of $5\,\mu \,F$ by connecting a $d.c$. source of $20\, kV$ is……$kJ$

A body of capacity $4\,\mu \,F$ is charged to $80\,V$ and another body of capacity $6\,\mu \,F$ is charged to $30\,V$. When they are connected the energy lost by $4\,\mu \,F$ capacitor is…….$mJ$

A $5\, \mu F$ capacitor is charged fully by a $220\,V$ supply. It is then disconnected from the supply and is connected in series to another uncharged $2.5\;\mu F$ capacitor. If the energy change during the charge redistribution is $\frac{ X }{100} \;J$ then value of $X$ to the nearest integer is$…..$

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 area of each plate is $A,$ the energy stored in the capacitor is 

A condenser of capacity $50\,\mu F$ is charged to $10\;volts$. Its energy is equal to