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Homework Help: Dipole question

  1. Feb 9, 2008 #1
    1. The problem statement, all variables and given/known data
    OK I really would appreciate some help on this - just a point in the right direction would be great:

    The potential due to the electron in a hydrogen atom at distance r from the nucleus is

    V = kq[(exp(-2r/a) - 1)/r + (exp(-2r/a)/a]

    Where k=1/(4pie0) where e0 is the electric constant

    where a is constant and is a measure of the "size" of the atom. Find the magnitude of the electric field at a distance r from the nucleus, r<<a

    When an external electric field is applied, show that the atom develops a dipole moment. By considering the force on the nucleus caclulate the size of the dipole moment p. (the answer is 3pie0a^3)

    2. Relevant equations

    3. The attempt at a solution

    I think the first bit is q/4pieoar from taking the negative grad of the potential and then approximating r/a to zero

    However this would mean that the force due to the electron at the proton is infinite - help!
    Last edited: Feb 9, 2008
  2. jcsd
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