A spherical coductor of radius 12cm has a charge of `1.6 xx 10^(-7)C` distributed uniformly on its surface. What is the electric field (a) inside (b) just outside the sphere (c), at a point 18cm from the centre of the sphere ?

Explanation

`R=12 xx 10^(-2)m, Q=1.6 xx 10^(-7)C`
a. Zero
b. `E=(9 xx 10^(9) xx 1.6 xx 10^(-7))/((12 xx 10^(-2))^(2))=(9 xx 10^(9) xx 1.6 xx 10^(-7))/(12 xx 12 xx 10^(-4))=10^(5)NC^(-1)`
c. Here `R=18 xx 10^(-2)m`
Hence `E=(9 xx 10^(9)xx 1.6 xx 10^(-7))/(18 xx 18 xx 10^(-4))=4/9 xx 10^(5) approx 4.4 xx 10^(-4)NC^(-1)`