Two charged spheres of radii $10\, cm$ and $15\, cm$ are connected by a thin wire. No current will flow, if they have

In a certain charge distribution, all points having zero potential can be joined by a circle $S$. Points inside $S$ have positive potential and points outside $S$ have negative potential. A positive charge, which is free to move, is placed inside $S$

Derive an expression for electric potential at a point due to a system of $\mathrm{N}$ charges.

A thin spherical insulating shell of radius $R$ carries a uniformly distributed charge such that the potential at its surface is $V _0$. A hole with a small area $\alpha 4 \pi R ^2(\alpha<<1)$ is made on the shell without affecting the rest of the shell. Which one of the following statements is correct?

Find the equation of the equipotential for an infinite cylinder of radius ${{r_0}}$, carrying charge of linear density $\lambda $.

If the electric potential of the inner metal sphere is $10$ $ volt$ $\&$ that of the outer shell is $5$ $volt$, then the potential at the centre will be ......$volt$