Energy of electrons can be increased by allowing them

If a unit positive charge is shifted from a region of low potential to a region of high potential,then the electric potential energy of the system

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:

$A$ particle $A$ has charge $+q$ and particle $B$ has charge $+4q$,with each of them having the same mass $m$. When allowed to fall from rest through the same electric potential difference $V$,the ratio of their speeds $\frac{v_A}{v_B}$ will be:

The electric potential $V$ of a charged spherical shell depends on the distance $r$ from its center. Which of the following graphs represents this dependence?

Three charged particles having charges $q, -2q$,and $q$ are placed in a line at points $(-a, 0), (0, 0)$,and $(a, 0)$ respectively. The expression for electric potential at $P(r, 0)$ for $r \gg a$ is ...............