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
Zero
$6{q^2}/4\pi {\varepsilon _0}r$
${q^2}/4\pi {\varepsilon _0}r$
$12{q^2}/4\pi {\varepsilon _0}r$
Three charges $Q,( + q)$ and $( + q)$ are placed at the vertices of an equilateral triangle of side l as shown in the figure. If the net electrostatic energy of the system is zero, then $Q$ is equal to
Consider a system of three charges $\frac{\mathrm{q}}{3}, \frac{\mathrm{q}}{3}$ and $-\frac{2 \mathrm{q}}{3}$ placed at points $\mathrm{A}, \mathrm{B}$ and $\mathrm{C}$, respectively, as shown in the figure,
Take $\mathrm{O}$ to be the centre of the circle of radius $\mathrm{R}$ and angle $\mathrm{CAB}=60^{\circ}$
Figure:$Image$
Work done in moving a positive charge on an equipotential surface is
A charge of $5\,C$ is given a displacement of $0.5\,m$. The work done in the process is $10\,J$. The potential difference between the two points will be.......$V$
Two particles each of mass $m$ and charge $q$ are separated by distance $r_1$ and the system is left free to move at $t = 0$. At time $t$ both the particles are found to be separated by distance $r_2$. The speed of each particle is