Two charges of magnitude $+q$ and $-3q$ are placed $100 \, cm$ apart. The distance from $+q$ between the charges where the electrostatic potential is zero is ....... $cm$.

$A$ nerve fiber membrane separates two conducting fluids and maintains a constant potential difference. What is the order of this potential difference?

Define electron volt and convert it into Joule unit.

Four point charges each $+q$ are placed on the circumference of a circle of diameter $2d$ in such a way that they form a square. The potential at the centre is proportional to

Assertion : Electric potential and electric potential energy are different quantities.
Reason : For a system of a positive test charge and a point charge,electric potential energy $=$ electric potential.

$A$ 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 $-3Q$,the new potential difference between the same two surfaces is: