A charge $( - q)$ and another charge $( + Q)$ are kept at two points $A$ and $B$ respectively. Keeping the charge $( + Q)$ fixed at $B$, the charge $( - q)$ at $A$ is moved to another point $C$ such that $ABC$ forms an equilateral triangle of side $l$. The net work done in moving the charge $( - q)$ is

  • A

    $\frac{1}{{4\pi {\varepsilon _0}}}\frac{{Qq}}{l}$

  • B

    $\frac{1}{{4\pi {\varepsilon _0}}}\frac{{Qq}}{{{l^2}}}$

  • C

    $\frac{1}{{4\pi {\varepsilon _0}}}Qql$

  • D

    Zero

Similar Questions

A point charge is surrounded symmetrically by six identical charges at distance $r$ as shown in the figure. How much work is done by the forces of electrostatic repulsion when the point charge $q$ at the centre is removed at infinity

In free space, a particle $A$ of charge $1\,\mu C$ is held fixed at a point $P.$ Another particle $B$ of the same charge and mass $4\,\mu g$ is kept at a distance of $1\,mm$ from $P$. If $B$ is released, then its velocity at a distance of $9\,mm$ from $P$ is [ Take $\frac{1}{{4\pi {\varepsilon _0}}} = 9 \times {10^9}\,N{m^2}{C^{ - 2}}$ ]

  • [JEE MAIN 2019]

Calculate potential energy of a point charge $-q$ placed along the axis due to a charge $+ Q$ uniformly distributed along a ring of radius $R$. Sketch $P.E.$ as a function of axial distance $z$ from the centre of the ring. Looking at graph, can you see what would happen if $-q$ is displaced slightly from the centre of the ring (along the axis) ?

A charge of $8\; mC$ is located at the origin. Calculate the work done in $J$ in taking a small charge of $-2 \times 10^{-9} \;C$ from a point $P (0,0,3\; cm )$ to a point $Q (0,4\; cm , 0),$ via a point $R (0,6\; cm , g \;cm )$

Explain electric potential energy. Show that the sum of kinetic energy and electric potential energy remains constant.