Potential is the capacity to do work  in a given geometry. An accumulation of electrical charge Q exerts a force F on another charge q at a distance r to reveal its potential energy U by Coulomb’s constant k, in the relationship U=Qqk/r observable by a measurable force F=Qqk/r^2 where Coulomb’s constant k= 1/(4piEo) = 9E9 NM^2/C^2 and Eo is the electrostatic permittivity of free space. The electric potential expression is Kq/r.