The magnitude of the electrostatic force exerted by one point charge (Q1) on another point charge (Q2) is directly proportional to the product of the magnitude of the charges and inversely proportional to the square of the distance (r) between them.
Electric Field
A region of space in which an electric charge experiences a force.
Electric field at a point
The electric field at a point is the electrostatic force experienced per unit positive charge placed at a point. •E=F/q