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Homework Help: Direction of the electric field

  1. May 17, 2009 #1
    1. The problem statement, all variables and given/known data
    The problem is as an attachment.

    3. The attempt at a solution

    The right answer is (a).
    However, I do not understand why.

    I draw two circles around the A and B. I let A's electric field go to anticlockwise direction, while that of B to clockwise direction.

    I got the result that electric field points from D to C.
    However, my answer is wrong.

    Attached Files:

  2. jcsd
  3. May 17, 2009 #2


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    Homework Helper
    Gold Member

    What do you mean anticlockwise and clockwise? The electrostatic field of a point charge points radially. If the charge is positive, it points outward radially. If the charge is negative, it points inward radially. The magnitude is proportional to q/r².
  4. May 17, 2009 #3
    Thank you for your answer!

    I got finally that the electric field is from A to B.
    I had confused electric field apparently with Magnetic field.

    The key in allowing me to understand the problem was to set a positive test mass between two charges.
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