In the circuit shown in the following figure,the potential difference across the $3 \mu F$ capacitor is: (in $V$)

There exists a uniform electric field $E = 4 \times 10^5 \, Vm^{-1}$ directed along the negative $x$-axis such that the electric potential at the origin is zero. $A$ charge of $-200 \, \mu C$ is placed at the origin,and a charge of $+200 \, \mu C$ is placed at $(3 \, m, 0)$. The electrostatic potential energy of the system is ........... $J$.

$1000$ small drops,each of radius $r$ and charge $q$,coalesce to form a single large drop. How many times greater is the potential of the large drop compared to the potential of a small drop?

$A$ parallel-plate capacitor is connected to a cell. Its positive plate $A$ and its negative plate $B$ have charges $+Q$ and $-Q$ respectively. $A$ third plate $C$, identical to $A$ and $B$, with charge $+Q$, is now introduced midway between $A$ and $B$, parallel to them. Which of the following are correct?

Four identical capacitors and three identical resistors are connected to a battery with $emf$ $E$ and internal resistance $r$ as shown in the figure. Find the charge on each capacitor.

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: