A solid sphere of radius $R$ is charged uniformly. At what distance from its surface is the electrostatic potential half of the potential at the centre?

A hollow conducting sphere of radius $R$ has a charge $( + Q)$ on its surface. What is the electric potential within the sphere at a distance $r = \frac{R}{3}$ from its centre

A table tennis ball which has been covered with conducting paint is suspended by a silk thread so that it hang between two plates, out of which one is earthed and other is connected to a high voltage generator. This ball

Four charges $2C, -3C, -4C$ and $5C$ respectively are placed at all the corners of a square. Which of the following statements is true for the point of intersection of the diagonals ?

In a region, if electric field is defined as $\vec E = \left( {\hat i + 2\hat j + \hat k} \right)\,V/m$ , then the potential difference between two points $A (0, 0, 0)$ and $B (2, 3, 4)$ in that region, is ......$V$

$64$ identical drops each charged upto potential of $10\,mV$ are combined to form a bigger dorp. The potential of the bigger drop will be $..........\,mV$