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Homework Help: Planck's constant calculation

  1. Apr 21, 2005 #1
    if you are given the stopping potential and the threshold frequency, how do you calculate Planck's constant from it?
     
  2. jcsd
  3. Apr 22, 2005 #2

    dextercioby

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    HINT:Assume all the energy of the electron/accelerated particle is converted into an energy of the photon...


    Daniel.
     
  4. Apr 22, 2005 #3
    ive used E=hf
    hf= Kmax + PHI
    Kmax=eV

    all it does is bring me round and round
     
  5. Apr 22, 2005 #4

    dextercioby

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    Hold on a second.Are talking about Bremsstrahlung,or photoelectrical effect...?I though u meant the former,but apparently i was wrong.Usually there's the plot KE vs incoming photon's frequency and u find "h" from the slope...

    Daniel.
     
  6. Apr 22, 2005 #5
    we are given a graph of stopping potential (y-axis) vs frequency (x-axis) thats it
     
  7. Apr 22, 2005 #6
    the stopping potential hits 0 at threshold frequency of 43.9 e13 Hz
     
  8. Apr 22, 2005 #7

    dextercioby

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    Well,the stopping potential is

    [tex] V=\frac{KE_{particle}}{q_{particle}} [/tex]

    Either way,u need the slope of that line.

    Daniel.
     
  9. Apr 22, 2005 #8
    but we are not iven the E of the particle?
     
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