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XRAY - Mosley Question

  1. Aug 29, 2006 #1
    Hi, Im an amateur to physics, am trying to understand what Mosely actually did when he used 'K' and 'L' waves to derive atomic numbers of elements.

    Can someone please tell me what exactly the 'K' and 'L' waves are, respectively?

    What is a 'K' wave and what does it measure?
    What is a 'L' wave and what does it measure?

    THANKS !
  2. jcsd
  3. Aug 29, 2006 #2
    The K and L lines refer to certain atomic transitions. K electrons are the most tightly bound electrons in atoms. When a K electron is knocked off from an atom and the hole left behind is filled by an electron from a higher energy level radiation corresponding to the energy difference is emitted. When an electron is knocked off from one energy level above the K electrons (called L ) and the hole is filled with an electron from an energy level above L you get the L lines. The energies of the emission lines are element specific and depend on the atomic numbers.

    I don't know how clear I was being since I don't know your background but feel free to ask further questions.
  4. Aug 29, 2006 #3


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    1. The physics of the atomic electron was not very well understood at Moseley's (and Bohr's) time (not nearly as well as it was, about 50 years after), though it was a significant leap forward from previous knowledge.

    2. The K, L ,... structure is nothing but the n=1,2,... electronic shell description provided by Bohr (published a couple or so years before Moseley published his experimental results). These numbers loosely translate to the ratio between the circumference of each Bohr orbit and the wavelength of the electron in that orbit.

    3. [itex]K_{\alpha }, K_{\beta }, ...[/itex] are designations for characteristic x-rays emitted by an electron dropping down through, 1,2,... levels to reach the K-shell. A similar notation is used for the other shells.
  5. Aug 29, 2006 #4
    XRAY Question - Inha

    thank you very much for your reply! So then K and L are simply physical positions of displacement?

  6. Aug 29, 2006 #5
    Gokul43201 - XRAY QUESTION

    Thank you for your reply, very helpful and informative. I believe I understood most of what you described below but am still a bit fuzzy on the overall concept.....

    Gokul, is there any sort of similiar 'thing' to a K or L in nature, some sort of analogy to understand it better by, or if we were working with a simple type of geometry or physical mechanism, how might they be conceptualized.... any ideas?

  7. Sep 2, 2006 #6


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    Start here: http://www.colorado.edu/physics/2000/quantumzone/bohr.html [Broken]

    Click the NEXT button at the bottom of the page when you complete it. At the end of the discussion on Bohr orbits (at about the third page), you'll see a link to X-rays - follow that link.
    Last edited by a moderator: May 2, 2017
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