$A$ conducting sphere of radius $R = 20 \ cm$ is given a charge $Q = 16 \ \mu C$. What is the electric field $\overrightarrow{E}$ at the centre?

An infinite non-conducting sheet has a surface charge density $\sigma = 0.10 \, \mu C/m^2$ on one side. How far apart are equipotential surfaces whose potentials differ by $50 \, V$?

$A$ thin disc of radius $b = 2a$ has a concentric hole of radius $a$ in it (see figure). It carries uniform surface charge $\sigma$. If the electric field on its axis at height $h$ $(h << a)$ from its centre is given as $Ch$,then the value of $C$ is:

As shown in the figure,a charged ball $B$ is suspended from a large charged conducting plate by a silk thread $S$ making an angle $\theta$ with the plate. The surface charge density $\sigma$ of the plate is proportional to ........

Explain by graph how the electric field by a thin spherical shell depends on the distance of a point from the centre.

If the linear charge density of a cylinder is $4 \mu C m^{-1}$,then the electric field intensity at a point $3.6 \ cm$ from the axis is: