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

  1. Feb 4, 2012 #1
    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. jcsd
  3. Feb 5, 2012 #2


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    Science Advisor
    Homework Helper

    welcome to pf!

    hi durhamisnuts! welcome to pf! :wink:

    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! :smile:
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