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Homework Help: Xray characteristic

  1. Mar 15, 2015 #1
    1. The problem statement, all variables and given/known data
    What are the energies of the characteristic Kα line and Kβ lines?

    2. Relevant equations
    K-shell ( n =1):-69.5 keV
    L-shell ( n =2 ): -11.3 keV
    M-shell ( n =3 ): -2.30 keV
    Z = 74
    E = (energy level) (Z-1)2/n2

    3. The attempt at a solution
    for alpha i have
    (-11.3keV) (74-1)2/22 for n =2

    i know to find the energy characteristic i need to go from n=1 to n=2. so i know E = E1-E2
    but for n=1 do use the energy level of the Kshell or the energy level of the Lshell?
    in the lecture notes the instructed used the same energy level but didnt specify which one.
  2. jcsd
  3. Mar 16, 2015 #2


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    The emmission occur when the electron transits from a higher energy level to a lower energy level,
    eg E2 -E1
    The Kα line is produced by transitions from the L to the K shell and the Kβ for transitions
    from the M to the K shell - see HyperPhysics X-ray transitions.
  4. Mar 16, 2015 #3
    Ok thank you. So it's E2-E1? My instructor did it the other way.

    But I still don't know which energy level to use. Like I said my instructor used the same energy level twice. She didn't specify if it was the Kshell or the Lshell.
  5. Mar 16, 2015 #4


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    The picture Andrevs link is clear enough !
    Kα radiation is emitted when the energy of the electron goes down from E2 = -11.3 keV to E1 = -69.5 keV
  6. Mar 16, 2015 #5
    ok i get it guys. i was misinterpreting the question as well as the procedure to solve it.
  7. Mar 16, 2015 #6
    thank you!
  8. Mar 16, 2015 #7


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    You're welcome.
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