Ignore
the sizes of A and B in comparison to the separation between their
centres Solution Let the original charge on sphere A be q and that on B be
q¢ At a distance r between their centres, the magnitude of the
electrostatic force on each is given by
F
rqq
=
′
41
0
2
πε
neglecting the sizes of spheres A and B in comparison to r When an
identical but uncharged sphere C touches A, the charges redistribute
on A and C and, by symmetry, each sphere carries a charge q/2