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Homework Help: Electric field just beyond surface of proton

  1. Feb 1, 2009 #1
    1. The problem statement, all variables and given/known data

    If a proton is considered a uniform ball of charge of radius 1.0x10-15m, what is the
    electric field just beyond its surface?

    2. Relevant equations

    Gauss's law?

    3. The attempt at a solution

    I followed a problem in the book that found an equation for the electric field of a uniformly charged sphere. I treated the proton as a uniform sphere of charge, so that the same equation could be applied.

    The equation was E = (1/4piE0)(Q/r^2)

    *E0 is constant 8.85 x 10^-12.

    So I just plugged in charge of electron and radius r of the proton.
    Last edited: Feb 1, 2009
  2. jcsd
  3. Feb 1, 2009 #2


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    Staff Emeritus
    Science Advisor
    Gold Member

    That looks fine. The result can of course be derived from Gauss' law. Remember that a proton has the same magnitude of charge as an electron but different sign.
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