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Homework Help: Energy directly proportional to frequency

  1. Apr 28, 2008 #1
    VERY SIMPLE!!! Please help!! - Energy of a gamma ray photon...

    1. The problem statement, all variables and given/known data

    The frequency of gamma radiation is 10[tex]^{22}[/tex] Hz. What is the energy of each gamma ray photon?
    Planck's constant, h, is equal to 6.6 x 10[tex]^{-34}[/tex] J*s.

    2. Relevant equations

    Energy = hf

    3. The attempt at a solution

    I'm having a problem with the units...

    Energy = (6.6 x 10[tex]^{-34}[/tex] J*s)(10[tex]^{22}[/tex] Hz)
    = (6.6 x 10[tex]^{-34}[/tex] J*s)(10[tex]^{22}[/tex] vib/s)
    = (6.6 x 10[tex]^{-34}[/tex] J)(10[tex]^{22}[/tex] vib)
    = 6.6 x 10[tex]^{-12}[/tex] J

    What happens to the 'vibration' unit?
    (note: I changed the Hz to vib/s. Is that correct?)
    Last edited: Apr 28, 2008
  2. jcsd
  3. Apr 28, 2008 #2
    Hz = 1/sec

    J*sec*Hz = (J*sec)/sec = J (Energy)
  4. Apr 28, 2008 #3
    Thank you!
  5. Apr 28, 2008 #4


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    Homework Helper

    Well a vibration per second is the same as just saying [itex]s^{-1}[/itex] I guess...why? Not too sure.
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