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Homework Help: Kinetic energy of an electron

  1. May 13, 2008 #1
    1. The problem statement, all variables and given/known data
    If an electron has a measured wavelength of 0.850 x 10^-10 m, what is its kinetic energy?

    2. Relevant equations
    I'm not sure.

    3. The attempt at a solution
    And once again, I'm not too sure. Where do I start?
  2. jcsd
  3. May 13, 2008 #2


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    Staff Emeritus
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    Homework Helper

    Find an equation in your textbook that deals with the wavelength of electrons or particles in general. That would be a start.
  4. May 13, 2008 #3
    Well, I've got this:

    I'm not sure if it's one to use.

    E = hc/[tex]\lambda[/tex]

    Similarly, I have this one:


    However, I'm not sure where or how to use it in this instance, or if I have to use it at all.

    Man, this stuff is getting tough. I was doing well there for a while too...
  5. May 13, 2008 #4


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    Homework Helper

    No, this equation will not work. Look back in your notes and try to figure out why.

    Look up "de Broglie wavelength."
  6. May 13, 2008 #5
    Aha! That is all I needed to know.

    Thanks a lot!
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