$N$ identical spherical drops charged to the same potential $V$ are combined to form a big drop. The potential of the new drop will be

A non-conducting ring of radius $0.5\,m$ carries a total charge of $1.11 \times {10^{ - 10}}\,C$ distributed non-uniformly on its circumference producing an electric field $\vec E$ everywhere in space. The value of the line integral $\int_{l = \infty }^{l = 0} {\, - \overrightarrow E .\overrightarrow {dl} } \,(l = 0$ being centre of the ring) in volt is

$1000$ small water drops each of radius $r$ and charge $q$ coalesce together to form one spherical drop. The potential of the big drop is larger than that of the smaller drop by a factor of

Calculate potential on the axis of a ring due to charge $Q$ uniformly distributed along the ring of radius $R$.

In the following figure two parallel metallic plates are maintained at different potential. If an electron is released midway between the plates, it will move

Charges are placed on the vertices of a square as shown. Let $E$ be the electric field and $V$ the potential at the centre. If the charges on $A$ and $B$ are interchanged with those on $D$ and $C$ respectively, then