A spherical conductor of radius 12 cm has a charge of `1. 6 xx 10^(-7) C ` distributed uniformly on its surface. What is the electric field
inside the sphere ?

Explanation

W should know that the electric field everywhere inside the charged spherical conductor is zero and for the points outside its behaviour is as if a point charge is placed at its centre.
(a) Electric field inside the spherical conductor will be zero as there is no charge inside it.
(b) Electric field just outside the sphere can be calculated as:
`E=(1)/(4pi epsilon_(0)) (q)/(r^(2))`
`rArr 9xx10^(9)xx(1.6xx10^(-7))/((12xx10^(-2))^(2))=(14.4xx10^(2))/(144xx10^(-4))=10^(5)NC^(-1)`
(c ) Electric field at a point at a distance `r_(1)=18` cm from the centre of the sphere can be calculated as:
`E = (1)/(4pi epsilon_(0)) (q)/(r_(1)^(2))`
`rArr 9xx10^(9)xx(1.6xx10^(-7))/((18xx10^(-2))^(2))=4.44xx10^(4)NC^(-1)`