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Another Electrical Field Question

  1. Nov 27, 2006 #1
    A test Charge of +1.0x10^-6 C is 40cm from a charged sphere of
    3.2x10^-3 C.

    a)how much work was required to move it there from a point 1.0x10^2m away from the sphere

    b)how many electrons were gained or lost from the test object to create the charge?

    Given: q1 = 1.0x10^-6 C q2 = 3.2x10^-3 C

    Would i first need to calculate: Fe = k (q1)(q2)/r2 ? and then plug that into W = F (delta D)
  2. jcsd
  3. Nov 27, 2006 #2


    User Avatar

    Staff: Mentor

    I don't think you can just plug it in -- You can integrate the force multiplied by delta-d as one charge is brought from the initial separation into the final configuration....
  4. Nov 27, 2006 #3
    i still dont understand how to do this question.. please someone help me !!
  5. Nov 27, 2006 #4
    I don't understand the question in part b.

    Part a) recall that the work done by a conservative force is equal to the negative integral of force dot displacement.
  6. Mar 18, 2007 #5
    For part b) only concern yourself with the test charge. It is +1.0*10^-6 C.

    How many electrons were gained or lost from the test object to create that charge?
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