1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Atomic Physics - Xrays and energy

  1. Sep 27, 2010 #1
    1. The problem statement, all variables and given/known data
    5 The energy levels of a molybdenum atom are approximately:
    K shell ….. – 20.00 KeV
    L shell …... – 2.52 KeV
    M shell …... – 0.23 KeV

    i) Estimate the energy of the Kα, K[tex]\beta[/tex] and Lα x-ray emissions.
    ii) What are the wavelengths of these emissions?

    2. Relevant equations

    3. The attempt at a solution

    I think K[tex]\alpha[/tex] is from L shell to k shell??
    so EK[tex]\alpha[/tex]=-2.52KeV--20KeV

    and the K[tex]\beta[/tex] is from M shell to K shell?
    then find the difference again for the energy

    I don't know what the L[tex]\alpha[/tex] is but possibly L shell to ground state or M shell to L shell??

    not sure if anything im doing there is right?

    shouldn't be hard once I have energy's
    E=hf so E=hc/[tex]\lambda[/tex]

    not sure if anything im doing here is right???

    Thanks for any help!
  2. jcsd
  3. Sep 27, 2010 #2


    User Avatar
    Homework Helper

  4. Sep 27, 2010 #3
    Thanks ehild and wiki,
    so the Lα transition is from M to L.
    I'm a bit confused as to whether or not the element is relevant to any of the calculations, from what I read on wiki it seems related by the amount of energy gained form each transition but since I have those values I shouldn't even need to know that the element is molybdendum?
    also I did the wave length calculation for the first transition and it came out to 1.24*10^-9m, this seems about right for an xray? (changed energy from KeV to J)

  5. Sep 27, 2010 #4


    User Avatar
    Homework Helper

    The x-ray lines are named by the letter of the final state. The element is not relevant as you were given the level energies. Check the magnitude of the wavelength, I got a different result.

  6. Sep 28, 2010 #5
    Yeah, I converted 17.48eV instead of 17.48KeV
    now I get 7.1*10^-11 m?????
    seems like a tiny wavelength.
  7. Sep 28, 2010 #6


    User Avatar
    Homework Helper

    X rays are of very short wavelength. Read the first sentences of the article.

  8. Sep 28, 2010 #7
    Thanks for helping ehild!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook