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Homework Help: Wavelength of a photon homework

  1. Jun 25, 2007 #1
    what is the wavelength of a photon emitted when a hydrogen electron drops from the n = 6 to the n = 3 level?
    (E1 = -13.6 eV and Planck's constant is 6.626 * 10^-34 J s)
  2. jcsd
  3. Jun 25, 2007 #2

    Doc Al

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    Staff: Mentor

    Look up the Bohr model for hydrogen.
  4. Jun 25, 2007 #3


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    Or take a quantum mechanics book which will tell you that
    [tex]E_n = - \frac{m}{2 \hbar^2} \left( \frac{e^2}{4 \pi \epsilon_0} \right)^2[/tex]
    are the energy levels of a hydrogen atom (I checked this in Mathematica, filling in the numbers and n = 1 indeed gives -13.6057 ElectronVolt :D).

    [edit] In fact, [tex]E_n = \frac{E_1}{n^2}[/tex] (Griffiths, Introduction to Quantum Mechanics, p. 149, [4.70]). Now if that doesn't make it easy on you, I give up :) [/edit]
    Last edited: Jun 25, 2007
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