Write three different formulas of energy stored in capacitor.

Energy per unit volume for a capacitor having area $A$ and separation $d$ kept at potential difference $V$ is given by

The lower plate of a parallel plate capacitor is supported on a rigid rod. The upper plate is suspended from one end of a balance. The two plates are joined together by a thin wire and subsequently disconnected. The balance is then counterpoised. Now a voltage $V = 5000\, volt$ is applied between the plates. The distance between the plates is $d =5\, mm$ and the area of each plate is $A = 100 cm^2.$ Then find out the additional mass placed to maintain balance.......$g$ [All the elements other than plates are massless and nonconducting] :-

If an electron enters into a space between the plates of a parallel plate capacitor at an angle $\alpha $ with the plates and leaves at an angle $\beta $ to the plates, the ratio of its kinetic energy while entering the capacitor to that while leaving will be

A series combination of $n_1$ capacitors, each of value $C_1$ is charged by a source of potential difference $4\, V.$ When another parallel combination of $n_2$ capacitors, each of value $C_2,$ is charged by a source of potential difference $V$, it has the same (total) energy stored in it, as the first combination has. The value of $C_2,$ in terms of $C_1$ is then

As in figure shown, if a capacitor $C$ is charged by connecting it with resistance $R$, then energy is given by the battery will be