# Homework Help: Electric potential PRoblem , dont understand

1. Sep 21, 2008

### th3plan

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

In the picture i attached, particles with charges q1 = +7e and q2 = -15e are fixed in place with a separation of d = 23.9 cm. With V = 0 at infinity, what are the finite (a) positive and (b) negative values of x (in cm) at which the net electric potential on the x axis is zero?

I dont understand why for positive net electric potential is in the middle between them, and negative is to the left. Can someone explain this.

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2. Sep 21, 2008

### Staff: Mentor

For each of the three regions (x < 0, 0 < x < d, x > d), write an expression that describes the net potential as a function of position.

What's the electric potential surrounding a point charge?

3. Sep 21, 2008

### th3plan

How would i do that, my book doesnt require us to write functions. I dont know what the electric potential surround a point charge is

4. Sep 21, 2008

### Staff: Mentor

By "function" I just mean a mathematical formula.
There's no point in worrying about the potential from two charges until you understand how to find the potential from one charge. Look it up!