Question

A spherical conductor of radius 12 cm has a charge of $1.6\times {10}^{-7}$C distributed uniformly on its surface. What is the electric field

(a) inside the sphere

(b) just outside the sphere

(c) at a point 18 cm from the centre of the sphere?

Answer 1

(a) Since the charge at any point inside sphere is zero.
by Gauss law,$E=0.$

(b) Just outside, $E=q/4\pi {ϵ}_o{r}^2$
so, $E={10}^{5}N{C}^{-1}$

(c) $q=1.6\times {10}^{-7}C$

$r=18cm$
$E=q/4\pi {ϵ}_o{r}^2$
$E=4.4\times {10}^{4}N{C}^{-1}$