A solid conducting sphere of radius $3\mathrm{.}0$ cm has a charge of

$30$ nC distributed uniformly over its surface. Let A be a point

$1\mathrm{.}0$ cm from the center of the sphere, S be a point on the surface

of the sphere, and B be a point $5\mathrm{.}0$ cm from the center of the

q$3$

$\backslash$infty

sphere. What are the electric potential differences $($a$)$ VS $-$ VB

and $($b$)$ VA $-$ VB$?$