Potential due to Uniformly Charged Spherical Shell

$$V_{\mathrm{outside}} = \frac{1}{4\pi\epsilon_0} \frac{Q}{r}, \quad V_{\mathrm{surface}} = \frac{1}{4\pi\epsilon_0} \frac{Q}{R}, \quad V_{\mathrm{inside}} = \frac{1}{4\pi\epsilon_0} \frac{Q}{R}$$
Potential for shell radius $$R$$, charge $$Q$$. Inside: constant; outside: like point charge.