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Homework Help: Emission spectrum for Helium

  1. Sep 25, 2010 #1
    1. The problem statement, all variables and given/known data
    The numbers following are the results of a lab experiment to find the spectral lines of Helium in a gas discharge tube. The lines I got were roughly:

    703nm, 660nm, 590nm, 500nm, 490nm, 470nm, 450nm.

    The question is, what possible electron transitions could the electrons have went though?

    2. Relevant equations
    Energy level of hydrogen like atoms is given by:

    E= [(-Z^2)(R)]/n^2

    3. The attempt at a solution

    I'm getting some crazy answers like transitions from n=20 to n=5, or n=9 to n=5. Intuitively, this does not seem to be correct, although my intuition is based on the hydrogen atom which has visible lines only at n=x to n=2.

    So... is this correct?
  2. jcsd
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