There is a uniformly charged non-conducting solid sphere made of material of dielectric constant $1$. If the electric potential at infinity is zero,then the potential at its surface is $V$. If we take the electric potential at its surface to be zero,then the potential at the centre will be

The potential at a point,due to a positive charge of $100\,\mu C$ at a distance of $9\,m$,is

Define electric potential and explain it. Write its $SI$ unit and give its other units.

$A$ uniformly charged ring of radius $3a$ and total charge $q$ is placed in the $xy$-plane centered at the origin. $A$ point charge $q$ is moving towards the ring along the $z$-axis and has speed $v$ at $z = 4a$. The minimum value of $v$ such that it crosses the origin is

Four charges,each of value $Q = \frac{10}{3} \times 10^{-9} \ C$,are placed at the four corners of a square of side $a = 8 \ cm$. What is the electric potential at the center of the square?

Calculate the 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 the potential energy $(P.E.)$ as a function of axial distance $z$ from the centre of the ring. Looking at the graph,can you determine what would happen if $-q$ is displaced slightly from the centre of the ring along the axis?