A solid conducting sphere having a charge $Q$ is surrounded by an uncharged concentric conducting hollow spherical shell. Let the potential difference between the surface of the solid sphere and that of the outer surface of the hollow shell be $V$. If the shell is now given a charge of $-3Q$, the new potential difference between the same two surfaces is……$V$

Three isolated equal charges are placed at the three comers of an equilateral triangle as shown in figure. The statement which is true for net electric potential $V$ and net electric field intensity $E$ at the centre of the triangle is

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 ……$volt$

Potential at a point $x$-distance from the centre inside the conducting sphere of radius $R$ and charged with charge $Q$ is

A sphere of $4\, cm$ radius is suspended within a hollow sphere of $6\, cm$ radius. The inner sphere is charged to potential $3\, e.s.u.$ and the outer sphere is earthed. The charge on the inner sphere is…..$e.s.u.$