A circular ring carries a charge $Q$, the variation of electric field with distance $x$ measured from centre along axis for $x<<R$ is given by $E=\frac{kQx}{R^3}$ $[R\to$ Radius of Ring]. The maximum electric field on the axis will be [where $C=\frac{Q}{4\mathrm{\pi }{\epsilon }_0{R}^2}$ ]

A charge $q$ is placed just above the centre of a horizontal circle of radius $r$, and a hemisphere of this radius is erected about the charge. Compute the electric flux through the closed surface that consists of the hemisphere and the planar circle. Do not use Gauss' law.

Which one of the following is correct regarding order of electric field intensity?

A hemispherical surface of radius $R$ is located in a uniform electric field $E$, as shown. The flux of electric field through the surface is

A cylinder of height  $H$ ' and radius of cross-section $r$ ' is kept in uniform electric field $\overrightarrow{E}$ as shown in figure. The magnitude of flux that enters from left half of cylinder is

Find the flux through the disc.