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Homework Help: Potential between two particles

  1. Dec 24, 2009 #1
    If we have two particles +q and -q. then the potential between them is <0 and therefore they will attract to each other. but what will happen when r is almost 0 (since we have r in the denominator)???
  2. jcsd
  3. Dec 24, 2009 #2


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    Homework Helper

    Re: Potential

    The force of attraction gets larger as the distance diminishes.
    The distance can never be zero because charges have size and the distance is measured from center to center. When the charges touch, some or all will cancel.
  4. Dec 24, 2009 #3
    Re: Potential

    We cannot make the separation 0 between the two charges, however if you place a third particle very far away the force on the test particle from the difference in the charges will approximately cancel out.
  5. Dec 25, 2009 #4
    Re: Potential

    I understand that, but lets say that the particles don't have "size", then in r=0 the potential will be infinity. the force of the attraction will cause them to get closer until r=0 , so how the potential can grow to infinty?
  6. Dec 25, 2009 #5


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    Re: Potential

    It can't because the particles do have size! You can't say "let's ignore physics" and then ask what physics says!
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