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Potential Due to a Group of Point Charges

  1. Sep 23, 2009 #1
    1. The problem statement, all variables and given/known data


    2. Relevant equations


    3. The attempt at a solution

    First time: I got -1.468e-19 which is wrong.
    Second time: I got -6.407e-19 which is wrong.

    q1 = 3.337e-19 ???
  2. jcsd
  3. Sep 23, 2009 #2


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    Homework Helper

    can't quite follow your working, here's how I would look at it:

    q1 is located at distance d from the origin

    The graph gives the potential at the origin, as q2 charge is moved a distance x away from the origin.


    when the 2nd charge is at infinity, the potential at the origin, V, will be only due to q1, use this to calculate q1 in terms of V & d.

    Then pick a suitable point from you graph, the zero crossing, x = 8, seems the easiest to me,

    you know q1 is d from the origin & q2 is x from the origin, and the net potential is zero, us these facts to calculate q2.
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