Three charges $q, \sqrt 2q, 2q$ are placed at the corners $A, B$ and $C$ respectively of the square $ABCD$ of side $'a'$ then potential at point $'D'$

An infinite number of charges each equal to $0.2\,\mu C$ are arranged in a line at distances $1\,m, 2\,m, 4\,m, 8\,m......$ from a fixed point. The potential at fixed point is ......$kV$

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?

A solid conducting sphere, having a charge $Q$, is surrounded by an uncharged 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 $-4\, Q$, the new potential difference between the same two surface is......$V$

The electric field in a region surrounding the origin is uniform and along the $x$ - axis. A small circle is drawn with the centre at the origin cutting the axes at points $A, B, C, D$ having co-ordinates $(a, 0), (0, a), (-a, 0), (0, -a)$; respectively as shown in figure then potential in minimum at the point

A hollow metallic sphere of radius $R$ is given a charge $Q$. Then the potential at the centre is