I am a bit confused about electric potentials and potential energy. There are three key situations that are giving me trouble:(adsbygoogle = window.adsbygoogle || []).push({});

1)

If an electron is midway between to protons, the potential energy is -ke^{2}/r for both, and thus the total electric potential energy is twice that value. I see how to get this from the formulas, and I realize that potential energy is not a vector quantity but a scalar, but it still boggles my mind that the electron would have potential energy. What does it have the potential to do? The electric field cancels at that point and there should be no net force, right?

2) Conversely, if the electron were midway in between a proton and an electron, the sum of the two potential energies would equal zero, yet the electron would quickly move toward the proton. Why is this, because the electron will certainly move? Does this have something to do with the fact that we can choose how to define were V=0 is? It is just strange because both charges on either end of the electron in the center are trying to get it to do the same thing (move to the proton).

3) Finally, if we have a point charge that creates a potential difference in space, if you know the electric field, you can calculate using V=Ed. But say you don't, and that you define V=0 at infinity. To me that makes sense because V=kq/r, and if r tends to infinity, V tends to zero. But what happens as r approaches zero. It seems like V would become infinite, which I don't believe it does. Is this because the point charge has a finite radius in actuality, or is there something else that I am missing?

Any help or guidance would be much appreciated-- thank you!

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Confusion on Concept of Electric Potentials/Potential Energy

**Physics Forums | Science Articles, Homework Help, Discussion**