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Homework Help: Wavelengths of photon

  1. Feb 18, 2009 #1
    1. The problem statement, all variables and given/known data

    The wavelength of the photon emitted when a hydrogen atom undergoes a transition from the k state to the n = 1 state is around 94.8 nm. How much is k?

    2. Relevant equations

    1/lambda= 1.97x10^7(1/1^2-1/k^2)

    3. The attempt at a solution

    1/9.48x10^-8=1.097x10^7(1-1/k^2)
    10548523,71=1.097x10^7(1-1/k^2)
    .9615791437=1-1/k^2
    -.03384208563=-1/k^2
    26.02753028=k^2
    k=5.1 i thought it had to be an integer? do i just round off?

    and im also a bit confused because when i get the energy of transition= hc/lambda, it is equal to 1.31, but (energyK-energyN=energy of transition) .544-13.6= is not even close to 1.31 and i thought it was supposed to equal 1.31 (hf, energy transition) or is that only when the photon absorbs, :/ a bit confused help out please
     
  2. jcsd
  3. Feb 18, 2009 #2

    Tom Mattson

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    Gold Member

    Yes. [itex]k=5[/itex].

    You miscalculated. The transition energy is 13.1eV, not 1.31eV.
     
  4. Feb 18, 2009 #3
    o ok.
    stupid me i see what i did now.
    and btw
    how do you know when a photon is absorbing energy?
    is it when the photon energy is the same to the energy transition? but im kind of confused because i thought they were always equal to each other
     
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