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Homework Help: Escape velocity of an electron

  1. Feb 16, 2010 #1
    [tex]\sqrt{}[/tex]1. The problem statement, all variables and given/known data

    What is the escape speed (in m/s) of an electron launched from the surface of a 7.42 cm diameter glass sphere that has been charged to 7.04 nC?

    2. Relevant equations


    3. The attempt at a solution
    here is what i did
    kqq/r = 1/2mv^2
    solve for v
    i used q = 7.42 square
    and mass of electron = 9.11*10^-31
    and r = 0.0704/2
    ....but still my answer is wrong
  2. jcsd
  3. Feb 16, 2010 #2


    User Avatar
    Homework Helper
    Gold Member

    I believe you have the value of the sphere's charge, and the diameter of the sphere interchanged.
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