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Magnetic field problem

  1. Feb 10, 2007 #1
    1. The problem statement, all variables and given/known data
    In an experiment you find that a small styrofoam ball of mass m can be suspended in mid-air by an electric field of magnitude c pointing straight downward, towards the earth.

    Its looking for the charge on the styrofoam ball, and I have no equation to help me solve for it.

    2. Relevant equations
    Lol thats what I'm lookin for.

    3. The attempt at a solution
  2. jcsd
  3. Feb 10, 2007 #2


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    What is the equation for the force experienced by a charge q in an electric field E?
  4. Feb 10, 2007 #3
    k(q1)(q2) / l^2?
  5. Feb 10, 2007 #4


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    You are given the magnitude of the E field. Note that much emphasis was placed on q and E. The force is proportional to product of two things...
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