If potential at centre of uniformaly charged ring is $V_0$ then electric field at its centre will be (assume radius $=R$ )
$\frac{{{V_0}}}{R}$
$\frac{{{3V_0}}}{2R}$
$\frac{{{V_0}}}{2R}$
Zero
A point charge $q$ is situated at a distance $d$ from one end of a thin non - conducting rod of length $L$ having a charge $Q$ (uniformly distributed along its length) as shown in fig.Then the magnitude of electric force between them is
For shown situation of two dipoles the nature of forces between them are
The work done required to put the four charges together at the corners of a square of side $a$ , as shown in the figure is
The figure shows two parallel equipotential surfaces $A$ and $B$ kept a small distance $r$ apart from each other. $A$ point charge of $q$ coulomb is taken from the surface $A$ to $B$. The amount of net work done will be
If on the concentric hollow spheres of radii $r$ and $R( > r)$ the charge $Q$ is distributed such that their surface densities are same then the potential at their common centre is