How does the Electric Potential change when -q goes to -2q?

1. Feb 4, 2012

durhamisnuts

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

Imagine that a particle with positive charge +q is placed on the x axis at x=+a and a particle with negative charge -2q is placed on the x axis at x= -a. Find the potential at all points along the y axis.

2. Relevant equations

delta phi = -E dot dr

3. The attempt at a solution

This isn't a homework problem, it's just a problem in the book i'm working on to get a better understanding of electric potential. I was wondering if someone could explain electric potential to me, and i figured the easiest way would be with a problem. The answer is given in terms of k, q, a, and y.

I know that had the it been -q instead of -2q the answer would be zero, but I am not sure how the physics works when it is -2.

2. Feb 5, 2012

tiny-tim

welcome to pf!

hi durhamisnuts! welcome to pf!

potential is a scalar

(unlike electric field, which is a vector)

ie, it's just a number, it has no direction …

so to get the potential from two or more sources, you find the potential from each, and add them

it's that easy!