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A question about Electric Charge

  1. Sep 26, 2009 #1
    We know that the negative charge on the electron and the positive charge on the proton are equal. Suppose, however, that these magnitudes differ from each other by 0.00007%. With what force would two copper pennies, placed 1.2 m apart, repel each other? Assume that each coin contains 3 multiplied by 10^22 copper atoms. (Hint: A neutral copper atom contains 29 protons and 29 electrons.)

    (From your answer, it should be obvious that the magnitude of the charge on a proton and the charge on an electron cannot possibly differ by as much as the given percentage.)
     
  2. jcsd
  3. Sep 26, 2009 #2

    rl.bhat

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    Hi Daysi, welcome to PF.
    Read the rules of PF. Before you ask for help you have to show you efforts.
    What are the relevant equations you can use in the problem?
     
  4. Sep 26, 2009 #3
    ahh sorry. haven't read the rules yet.
    I'm sure we can use Coulomb's law.
    F=KQq/r²
     
  5. Sep 26, 2009 #4

    rl.bhat

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    Your relevant equation is correct.What are the different forces acting on one pennies by the other?
     
  6. Sep 26, 2009 #5
    Repulsive force and attractive force? and the repulsive one is slightly larger?
     
  7. Sep 29, 2009 #6
    and q=29e?
    I don't know how to do the rest...
     
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