Figure shows the variation of electric field intensity $E$ versus distance $x$. What is the potential difference between the points at $x=2 \,m$ and at $x=6 \,m$ from $O$ is ............. $V$

Calculate potential on the axis of a disc of radius $R$ due to a charge $Q$ uniformly distributed on its surface.

Write an equation for potential due to linear charge distribution. 

Consider two conducting spheres of radii ${{\rm{R}}_1}$ and ${{\rm{R}}_2}$ with $\left( {{{\rm{R}}_1} > {{\rm{R}}_2}} \right)$. If the two are at the same potential, the larger sphere has more charge than the smaller sphere. State whether the charge density of the smaller sphere is more or less than that of the larger one.

The variation of electrostatic potential with radial distance $r$ from the centre of a positively charged metallic thin shell of radius $R$ is given by the graph

As shown in the figure, charges $ + q$ and $ - q$ are placed at the vertices $B$ and $C$ of an isosceles triangle. The potential at the vertex $A$ is