Two conducting spheres of radius 01 cm are charged by transf

Two conducting spheres of radius 0.1 cm are charged by transferring 1012 electrons from one sphere to the other. What is the magnitude of the force between the spheres if their centers are 3 cm apart?

Solution

Charge on one sphere = +1012e and charge on other = -1012e where e=1. 6* 10^-19 c

since both are conducting they would act as point charge

so F = kq1q2/r^2 = 9*10^9 *1012*1012*1.6*10^-19*1.6*10^-19/( 3*10^-2)^2 =2.62 * 10^-19 N