Let $A, B$ and $C$ be the three points in a uniform electric field $(\overrightarrow{E})$ as shown. The electric potential 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 $K$.

Four charges are arranged at the corners of a square $ABCD$ of side $d$,as shown in Figure.
$(a)$ Find the work required to put together this arrangement.
$(b)$ $A$ charge $q_{0}$ is brought to the centre $E$ of the square,the four charges being held fixed at its corners. How much extra work is needed to do this?

Which of the following is a volt?

$A$ uniform electric field vector $E$ exists along the horizontal direction as shown. The electric potential at $A$ is $V_A$. $A$ small point charge $q$ is slowly moved from $A$ to $B$ along the curved path as shown. The potential energy of the charge when it is at point $B$ is

How much kinetic energy will be gained by an $\alpha$-particle in going from a point at $70\,V$ to another point at $50\,V$?