For a uniformly charged thin spherical shell, the electric...

The potential is constant inside the sphere as the electric field is zero inside the sphere. So, the value is given by

$V = \dfrac{Q}{4\pi{ε}_{0}R}$ for $r < R$

The potential at the surface is

$V = \dfrac{Q}{4\pi{ε}_{0}R}$

The potential outside the sphere starts decreasing and is given by the formula

$V = \dfrac{Q}{4\pi{ε}_{0}r}$ for $r > R$