Charges $+q$ and $-q$ are placed at points $A$ and $B$ respectively,which are a distance $2L$ apart. $C$ is the midpoint between $A$ and $B$. The work done in moving a charge $+Q$ along the semicircle $CRD$ is

$A$ particle of mass $m$ and charge $q$ is accelerated through a potential difference of $V$ volt. Its energy will be:

The potential at a distance $R/2$ from the centre of a conducting sphere of radius $R$ 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 $\int_{l = \infty }^{l = 0} { - \vec{E} \cdot d\vec{l} }$ (where $l = 0$ is the centre of the ring) in volts is:

Two spheres $A$ and $B$ of radius $a$ and $b$ respectively are at the same electric potential. The ratio of the surface charge densities of $A$ and $B$ is

$A$ charge $Q$ is distributed over three concentric spherical shells of radii $a, b, c$ $(a < b < c)$ such that their surface charge densities are equal to one another. The total potential at a point at distance $r$ from their common centre,where $r < a$,would be