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Homework Help: Potential difference formula

  1. Jan 30, 2008 #1
    1. Consider point a which is 70 cm north of a -4.2 µC point charge, and point b which is 74 cm west of the charge (Fig. 17-23).
    (a) Determine Vba = Vb - Va.
    (b) Determine Eb - Ea.
    Direction (counterclockwise from east is positive)

    2. Vb-Va=(EPEb/q)-(EPEa/q)

    3. I thought I would use that formula since that is what I need, but I don't know how to get V. Please help!
  2. jcsd
  3. Jan 30, 2008 #2


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    Homework Helper
    Gold Member

    That formula is correct but work simplify it a little bit.

    What is the electric potential energy at a point equal to? If you know, then fill that in to the formulas you have to simplify. If you can do this you should end up with some workable formulas.
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