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Electromagnetic Radiation

  1. Oct 26, 2006 #1
    The energy (in joules) of an electron energy level in the Bohr atom is given by the expression: [tex]E_{n}[/tex]= -2.179 x [tex]10^-18/n^2 J[/tex]where n is the principal quantum number for the energy level. What is the frequency in Hz of the electromagnetic radiation absorbed when an electron is raised up from level with n = 4 to that with n = 9?

    I'm unsure of the the formula to use, or even the first step. Any ideas??
     
  2. jcsd
  3. Oct 26, 2006 #2

    marcusl

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    First use your formula to calculate the energy difference between the two levels. Second, relate that to frequency. Look in your book for the formula giving energy of a photon (hint: it involves Planck's constant). You can show us what you get if you still have questions.
     
  4. Oct 26, 2006 #3
    use the equation [tex] \Delta E = R_{H}^{*} (\frac{1}{n_{f}^{2}} - \frac{1}{n_{i}^{2}}) = hv [/tex]
     
  5. Oct 26, 2006 #4
    Ok, so I plugged both of the numbers (4 and 9) into the equation. Then I subtracted answer #1 from answer #2. Then I divided this number by h (6.626E-34). Am I doing this correctly?
     
  6. Oct 26, 2006 #5

    marcusl

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    Yes, exactly.
     
  7. Oct 27, 2006 #6
    this is great!, I could learn something here....
     
  8. Oct 27, 2006 #7
    Great I got the answer, thanks for all the help!
     
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