Write an equation for the electrostatic potential of a negative point charge.

(N/A) The electrostatic potential $V$ at a distance $r$ from a point charge $q$ is given by the formula: $V = \frac{1}{4\pi\epsilon_0} \frac{q}{r}$.
For a negative point charge,we substitute $q = -|q|$.
Therefore,the equation for the electrostatic potential of a negative point charge is: $V = -\frac{1}{4\pi\epsilon_0} \frac{|q|}{r}$,where $\epsilon_0$ is the permittivity of free space.