The electric intensity due to an infinite cylinder of radius $R$ and having charge $q$ per unit length at a distance $r(r > R)$ from its axis is

$A$ hollow metal sphere of radius $R$ is uniformly charged. The electric field due to the sphere at a distance $r$ from the centre is:

Two infinitely long thin straight parallel wires are kept at a perpendicular distance of $2R$, having uniform linear charge densities $+\lambda$ and $-\lambda$ respectively. The magnitude of the electric field at the midpoint between the two wires will be . . . . . . .

$A$ solid metal sphere of radius $R$ having charge $q$ is enclosed inside a concentric spherical shell of inner radius $a$ and outer radius $b$ as shown in the figure. The approximate variation of the electric field $\overrightarrow{E}$ as a function of distance $r$ from the centre $O$ is given by:

In a uniformly charged sphere of total charge $Q$ and radius $R$,the electric field $E$ is plotted as a function of distance $r$ from the center. The graph which would correspond to the above is:

$A$ sphere of radius $R$ has a uniform distribution of electric charge in its volume. At a distance $x$ from its centre,for $x < R$,the electric field is directly proportional to