Question

What is the electric potential 15.0 cm from a point charge?

Answer 1

The electric potential $V$ at the distance $r$ from the point charge $q$ is given by

$$V=k\frac{q}{r}$$

$$V=9*10^9\: {\rm N\cdot m^2/C}*\frac{q\: \rm C}{0.15\:\rm m}$$