# How do you work out the potential difference between two point charges?

1. Apr 19, 2012

### CraigH

I'm having trouble trying to understand what a volt is, and I thought this question might be able to help me understand, so..

For example: If there are 10^6 electrons in one place, and 100 electrons in a different place, what will the potential difference between these two places be.
Also, if a wire was connected between these two places, and this wire had a resistance of 1 ohm, what would the current be?
Thanks

2. Apr 19, 2012

### CraigH

I'v just found out that the fact that they are point charge's makes this question impossible to answer, so lets say at both sides the electrons are equally spread out in a 1m^3 metal box.

Last edited: Apr 19, 2012
3. Apr 20, 2012

### Staff: Mentor

This is still not well-defined. The field and therefore the potential difference will depend on the shape of your box and the distance between the boxes.

You could consider a large capacitor made out of two parallel plates with well-defined surface densities of electrons on both sides. There, it is possible to calculate the potential difference without complex calculations.

4. Apr 20, 2012

### CraigH

Okay, but am I right in thinking that the reason there is a potential difference is because there is more charge in one place than the other?

5. Apr 21, 2012

### Staff: Mentor

That can give a potential difference. But it depends on the charge distribution, too.
You can get a potential difference between two objects with the same number of charges each, too, for example if one of the objects is smaller than the other one.