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Homework Help: Electric Field and Potential

  1. Feb 10, 2012 #1
    1. The problem statement, all variables and given/known data

    For each of the following arrangements of two point charges, find all the points along the line passing through both charges for which the electric potential V is zero (take V = 0 infinitely far from the charges) and for which the electric field E is zero. (Use the following as necessary: Q, d. Enter 0 or ∞ if necessary.)

    (a) charges +Q and +2Q separated by a distance d
    V = 0: x =
    E = 0: x =

    (b) charges −Q and +2Q separated by a distance d
    V = 0: x =
    y =
    E = 0: y =
    2. Relevant equations

    3. The attempt at a solution

    (a) V=0: X=∞
  2. jcsd
  3. Feb 10, 2012 #2
    You got the first part of a right (well they said points, so -∞ is also an solution), take a stab at the second part of a.

    For b you will need the relevant equations.
  4. Feb 10, 2012 #3
    For the second part I tried Q+1/4d but it was wrong. I thought that at that point the positive charges would even out at a net electric field of 0.
  5. Feb 10, 2012 #4
    What relevant equations should I refer to here?
  6. Feb 11, 2012 #5
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