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Quantum Mechanics (need help)

  1. Dec 2, 2008 #1
    1. The problem statement, all variables and given/known data

    1. A photon is emmited when an electron confinded to a box of length 10^-9 m undergoes energy level transition, and has a frequency of 2.50 x 10^15 Hz. Find the energy levels associated with emited radiation

    2. Relevant equations

    E=n^2h^2/8mL^2
    E=Hc/wavelength
    E= -13.61/n^2

    3. The attempt at a solution

    i have no clue

    1. The problem statement, all variables and given/known data
    compute the wavelength of an electron having speed a) 3 x 10^4 m/s b)0.1 x speed of light

    2. Relevant equations

    E=n^2h^2/8mL^2
    E=Hc/wavelength
    E= -13.61/n^2

    3. The attempt at a solution

    not sure


    1. The problem statement, all variables and given/known data
    A hydrogen discharge tube(lamp) is excited with energy 13.15 eV. How many possible lines would be obsererved in the emission spectrum of these atoms as a result of this exciation, and which ones would be visible. Visible range 4000A and 8000A

    2. Relevant equations

    E=n^2h^2/8mL^2
    E=Hc/wavelength
    E= -13.61/n^2

    3. The attempt at a solution
    something with factorial not sure how to though
     
    Last edited: Dec 2, 2008
  2. jcsd
  3. Dec 3, 2008 #2
    Initially, the electron is in some unknown stationary state. Then the electron emits a photon of "specific" energy and is now in a lower state. What is special about the energies associated with the different stationary states? They are quantized:

    [tex] E_{n} = \frac{n^{2}\pi^{2}\hbar^{2}}{2mL^{2}} [/tex]

    Do you got it now? By the way, where did the 8 come from in your formula?
     
  4. Dec 3, 2008 #3
    im not sure its in my forumla book, where did you get the pie from i dont have that in the equation
     
  5. Dec 3, 2008 #4

    malawi_glenn

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    He is using h-bar.

    [tex]\hbar = h/(2\pi )[/tex]

    And you have all the equations you need for this, why don't you make a serious attempt to solve it?
    If you have NO clue, make a (motivated) guess!
     
  6. Dec 3, 2008 #5

    malawi_glenn

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    Science Advisor
    Homework Helper

    He is using equation with h, placks constat, you are using formula with h-bar. Be careful! :-)
     
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