If the uniform surface charge density on an infinite plane sheet is $\sigma$,the electric field near the surface will be . . . . . . .

An $100 \ eV$ electron is fired directly towards a large metal plate having surface charge density $-2 \times 10^{-6} \ C \ m^{-2}$. The distance from where the electron is projected,so that it just fails to strike the plate,is: (in $mm$)

Consider a thin spherical shell of radius $R$ with its centre at the origin,carrying uniform positive surface charge density. The variation of the magnitude of the electric field $|\vec{E}(r)|$ and the electric potential $V(r)$ with the distance $r$ from the centre,is best represented by which graph?

$A$ force of $10 \; N$ acts on a charged particle placed between two plates of a charged capacitor. If one plate of the capacitor is removed,then the force acting on that particle will be ...... $N$.

$A$ uniformly charged thin spherical shell of radius '$R$' has a uniform surface charge density '$\sigma$'. It is made of two identical hemispherical shells held together by pressing them with a force '$F$' as shown. '$F$' is proportional to [$\epsilon_0$ = permittivity of free space].

The electric field in a region is radially outward with magnitude $E = A r_0$. The charge contained in a sphere of radius $r_0$ centered at the origin is