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Homework Help: Electric Potential

  1. Jan 17, 2008 #1
    1. The problem statement, all variables and given/known data
    Moving a charge from point A, where the potential is 284 V, to point B, where the potential is 83 V, takes 9e-05 J of work. What is the value of the charge?

    2. Relevant equations

    3. The attempt at a solution
    I know this is a very easy problem but I am not getting the right answer...
    I thought it was just...
    Uel = qV
    q = Uel/V
    q = 9x10^-5 / (284-83) = 4.478 x 10^-7 C
  2. jcsd
  3. Jan 19, 2008 #2

    Tom Mattson

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    Staff Emeritus
    Science Advisor
    Gold Member

    If it takes positive work to move the charge from high potential to low potential, then the charge must be negative.
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