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

[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

 

[CraigH]

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

 

[mfb]

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.

 

[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?

 

[mfb]

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.