The figure shows three circular arcs,each of radius $R$ and total charge as indicated. The net electric potential at the centre of curvature is

An electric dipole is placed as shown in the figure. The electric potential (in $10^2 \ V$) at point $P$ due to the dipole is ($\epsilon_0 =$ permittivity of free space and $\frac{1}{4 \pi \epsilon_0} = K$):

$A$ 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:

The mass of a particle is $400$ times that of an electron and its charge is double that of an electron. The particle is accelerated by a potential difference of $5 \; V$. If the particle was initially at rest,what will be its final kinetic energy in $eV$?

Two electric charges of $9 \mu C$ and $-3 \mu C$ are placed $0.16 \ m$ apart in air. There will be a point $P$ on the line joining the two charges and between them where the electric potential is zero. The distance of $P$ from the $9 \mu C$ charge is: (in $m$)

Two metal spheres of radii $R_1$ and $R_2$ are charged to the same potential. The ratio of charges on the spheres is