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Homework Help: Atomic Energy Levels

  1. Aug 1, 2009 #1
    1. The problem statement, all variables and given/known data
    Couple of questions

    State the De Broglie Wavelength for electrons with an energy of 50eV


    the following is a picture is a diagram of the energy levels in Fe:
    What is the energy required to ionise Fe in in the ground state

    2. Relevant equations
    *lambda* = h/p = h/mv = h/sqr(2Em)

    3. The attempt at a solution
    for the first question i got 1.74x10^-10m but that is not the solution

    and for the next question

    is it -11.6 or +11.6
  2. jcsd
  3. Aug 1, 2009 #2


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    Homework Helper

    you mean

    [tex]\lambda = \frac{h}{m \sqrt{2Em}}[/tex]

    did you remember to multiply by the mass again in the denominator?

    We'd need to see the diagram to help you with the next part of the question.
  4. Aug 2, 2009 #3


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    Homework Helper

    If it's "energy required", it's positive; in this case it makes no sense to talk about adding a negative amount of energy.
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