THE ELECTRIC FORCE LAW

Since electrons, protons, and neutrons make up almost everything we see around us (except for photons or light itself), a description of the electric force between these three particles provides a fairly complete picture of the electric interaction, insofar as it affects our lives. For electrons, protons, and neutrons at rest, this interaction is completely summarized in Figure (1).
As we see, protons repel each other, electrons repel each other, and a proton and an electron attract each other. There is no electric force on a neutron. The strength of the electric force between these particles drops off as 1/r ² and has a magnitude shown in Equation 1. We know, to extremely high precision, that the attractive force between an electron and proton has the same strength as the repulsive force between two protons or two electrons, when the particles have the same separation r. It is surprising how complete a summary of the electric interaction Figure (1) represents. We have only shown the forces between the particles at rest.
But if you combine these results with the special theory of relativity, you can deduce the existence of magnetism and derive the formulas for magnetic forces. 

Figure 1: The electric interaction between protons and electrons at rest. There is no electric force on a neutron.