# Electric potential

Electric potential goes like the inverse of distance squared and the product of the two charges. But I can't see how this can produce V = IR.

## Answers and Replies

vanesch
Staff Emeritus
Gold Member
Electric potential goes like the inverse of distance squared and the product of the two charges. But I can't see how this can produce V = IR.
The relationship is very remote ! The first you cite is the potential of a *point charge in space*. The second (ohm's law) is the relationship between the motion and the potential distribution of a whole collection of charges within a certain material (which will have its influence on the dynamics).
Ohm's law is a material property (which doesn't always hold, btw), a bit like Hooke's law for the elastic behaviour of materials, while the first law you cited is more like, say, the law of Newtonian gravitation. You cannot derive Hooke's law from Newton's law of gravitation either.

Electric potential goes like the inverse of distance squared and the product of the two charges. But I can't see how this can produce V = IR.
The last time I saw, the potential went like one over distance (not squared!) and depended only on the source charge. What you say is true for the force between two point charges, though.

The last time I saw, the potential went like one over distance (not squared!) and depended only on the source charge. What you say is true for the force between two point charges, though.
Ooops. I typed too fast. 1/distance squared for electric force. 1/distance for potential.

robphy