# Relationship between electric forces

1. Sep 11, 2004

### malco97

I am wondering if there is some way for the force between two charges (calculated by Coloumb's law) and the force applied by a field on a charge.

2. Sep 11, 2004

### robphy

3. Sep 11, 2004

### malco97

Sorry,

What I am trying to do is find out how the electric potential of a radial field equation is derived. I have found a derivation by using Coulomb's Law and the equations for electric force, work etc however I do not understand the equation completely. This is because I do not know if the force between two charges (Coulomb's Law) and the force exerted on a charge by a field can be compared.

Thanks.

4. Sep 11, 2004

### Tide

They are equivalent. The force acting on a charge is related to the electric field by $\vec F = q \vec E$. In fact, that's how electric fields were defined.

5. Sep 12, 2004

### Gonzolo

Take Coulombs's law, separate a q, call the rest an electric field E defined by $$E = \frac{kQ}{r^2}$$.

That's pretty much all there is to it. Once E is defined in this way, it paves the way for all of electrostatics. The same E then contributes to describe Maxwell's electromagnetic theory in its entirety.

Last edited by a moderator: Sep 12, 2004