# Electrical potential

1. Feb 19, 2009

### synergix

1. The problem statement, all variables and given/known data

What is the electric potential at the point midway between charges of 7.0 microC and 3.0microC which are 3.0 m apart?

2. Relevant equations

Va=Va1+-Va2

V= Kq/r

3. The attempt at a solution
I know how to do the calculations I am just not sure about how to add the potentials I am pretty sure that since they are both positive and the charge is halfway between them then the electrical potential will be the difference between the two is that correct?

2. Feb 19, 2009

### AEM

Your last sentence has a typo in it. You say "the charge is halfway between them" You meant to say "the point is halfway between them" There is a difference between the implications of these two phrases.

Putting that aside, since the electric potential is a scalar (not a vector) you simply add the two potentials as indicated in your first equation. If you were adding up the electric fields, where there is a directional property to take into account because the electric field is represented by a vector then you would end up with a subtraction (in this case).

3. Feb 19, 2009

### synergix

ahh yes thank you.