Identical charges $(-q)$ are placed at each corner of a cube of side $b$. The electrostatic potential energy of a charge $(+q)$ placed at the center of the cube is:

The electrostatic potential energy of the given system of charges placed at the corners of a square of side $a$ is:

Two charges $q_1$ and $q_2$ are separated by a distance of $30\ cm$. $A$ third charge $q_3$,initially at $C$ as shown in the figure,is moved along the circular path of radius $40\ cm$ from $C$ to $D$. If the difference in potential energy due to the movement of $q_3$ from $C$ to $D$ is given by $\frac{q_3 K}{4 \pi \epsilon_0}$,find the value of $K$.

$A$ spherical shell of radius $10 \,cm$ is carrying a charge $q$. If the electric potential at distances $5 \,cm$, $10 \,cm$, and $15 \,cm$ from the centre of the spherical shell is $V_{1}$, $V_{2}$, and $V_{3}$ respectively, then:

If the electric potential of the inner shell of radius $a$ is $10\,V$ and that of the outer shell of radius $2a$ is $5\,V$,then the potential at the centre will be.....$V$

$A$ particle has a mass $400$ times that of an electron and a charge double that of an electron. It is accelerated by a potential difference of $5 \ V$. If the particle was initially at rest,what will be its final kinetic energy in $eV$?