Answer:
Given that the charge on the conductor is Q=40 x 10-12 C
radius is r=0.04m
the potential at an inner point is constant and is same as that on the sphere that is
Va=kQ/r
=9 x 109 x40 x 10-12 /0.04
=9V
the potential at a point R=0.05m is
Vb=kQ/R
=9 x 109 x40 x 10-12 /0.05
=7.2V
Hence the potential difference is Va-Vb=1.8V
Explanation: