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Homework Help: Net Electric Field

  1. Feb 2, 2009 #1
    A positive charge of +q1 is located 5.22 m to the left of a negative charge -q2. The charges have different magnitudes. On the line through the charges, the net electric field is zero at a spot 2.55 m to the right of the negative charge. On this line there are also two spots where the potential is zero. (a) How far to the left of the negative charge is one spot? (b) How far to the right of the negative charge is the other?

    E= kq1/5.22^2m + k(-q)/2.55^2m = 0
    I think that this is the first equation that I use. I am not sure if I have set it up right.

    and then I use this equation I think.
    kq1/x1+ k(-q)/5.22-x1=0?

    Overall, I just need someone to clarify PLEASE!
  2. jcsd
  3. Feb 3, 2009 #2


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    Hi ptdreamer! :smile:
    Yes, that's all good, but of course it only gives you one of the spots …

    how should you adjust the second equation to get the other one? :wink: