$A$ series combination of $N_1$ capacitors (each of capacity $C_1$) is charged to a potential difference $3V$. Another parallel combination of $N_2$ capacitors (each of capacity $C_2$) is charged to a potential difference $V$. The total energy stored in both combinations is the same. The value of $C_1$ in terms of $C_2$ is:

Two positrons $(e^+)$ and two protons $(p)$ are kept on four corners of a square of side $a$ as shown in the figure. The mass of a proton is much larger than the mass of a positron. Let $q$ denote the charge on the proton as well as the positron. Then,the kinetic energies of one of the positrons and one of the protons,respectively,after a very long time will be:

Initially $n$ identical capacitors are joined in parallel and are charged to potential $V$. Now they are separated and joined in series. Then

$A$ parallel plate capacitor of capacitance $C$ is connected to a battery and is charged to a potential difference $V$. Another capacitor of capacitance $2C$ is connected to another battery and is charged to a potential difference $2V$. The charging batteries are now disconnected and the capacitors are connected in parallel to each other in such a way that the positive terminal of one is connected to the negative terminal of the other. The final energy of the configuration is

$A$ capacitor of unknown capacity is connected across a battery of $V$ volt. The charge stored in it is $Q$ coulomb. When the potential across the capacitor is reduced by $V_1$ volt,the charge stored in it becomes $Q_1$ coulomb. The potential $V$ is

$A$ charged capacitor is disconnected from the battery and if the distance between the two plates of the capacitor is increased then . . . . . . .