Figure shows three circular arcs, each of radius $R$ and total charge as indicated. The net electric potential at the centre of curvature is
$\frac{Q}{{4\pi { \in _0}R}}$
$\frac{Q}{{2\pi { \in _0}R}}$
$\frac{2Q}{{\pi { \in _0}R}}$
$\frac{Q}{{\pi { \in _0}R}}$
Two electric charges $12\,\mu C$ and $ - 6\,\mu C$ are placed $20\, cm$ apart in air. There will be a point $P$ on the line joining these charges and outside the region between them, at which the electric potential is zero. The distance of $P$ from $ - 6\,\mu C$ charge is.......$m$
Two identical positive charges are placed at $x =\, -a$ and $x = a$ . The correct variation of potential $V$ along the $x-$ axis is given by
Three concentric metallic shells $A, B$ and $C$ of radii $a, b$ and $c (a < b < c)$ have surface charge densities $\sigma ,\, - \sigma $ and $\sigma $ respectively. then ${V_A}$ and ${V_B}$
A hollow metal sphere of radius $5\, cm$ is charged so that the potential on its surface is $10\, V$. The potential at the centre of the sphere is
A table tennis ball which has been covered with conducting paint is suspended by a silk thread so that it hang between two plates, out of which one is earthed and other is connected to a high voltage generator. This ball