(N/A) For a uniformly charged spherical shell of radius $R$ and total charge $q$,the electric potential $V$ is determined as follows:
$1$. Outside the shell $(r > R)$: The potential is equivalent to that of a point charge concentrated at the center: $V = \frac{kq}{r}$.
$2$. On the surface of the shell $(r = R)$: The potential is $V = \frac{kq}{R}$.
$3$. Inside the shell $(r < R)$: Since the electric field inside a charged spherical shell is zero,the potential remains constant and equal to the potential at the surface: $V = \frac{kq}{R}$.
Thus,the expressions are:
$V = \frac{kq}{r}$ for $r \geq R$
$V = \frac{kq}{R}$ for $r < R$