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Photoelectric Effects?

  1. Sep 10, 2009 #1
    I have a few questions on the Photoelectric Effect.

    First off, what wavelengths could be used to cause a photoelectric on Stainless Steel?

    What widely available metals have the lowest eV for the photoelectric effect?

    Could a UV light of 380nm work to cause a photoelectric effect on Stainless steel or aluminum? Or does it have to be the exact energy level?
  2. jcsd
  3. Sep 10, 2009 #2


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  4. Sep 10, 2009 #3
    Aluminium would be your best bet (it is one of the most common metals and has a fairly low work function (4.08 eV). However, this corresponds to a wavelength of 304nm, so 380nm isn't short enough. The photons in the 380nm light will only have 3.3eV, enough to ionise sodium, potassium, cesium and any other metals with only 1 electron in the outer shell. These metals are pretty hard to get hold of though I would imagine, so I'm not sure you could do any experiments of this kind without a different UV source!

    Source: http://hyperphysics.phy-astr.gsu.edu/HBASE/Tables/photoelec.html
  5. Sep 11, 2009 #4
    I understand now that it wouldnt work with 380nm. Looks like I would need something around 300nm. Too expensive for now...

    Thanks everyone for the help!!!
  6. Sep 19, 2009 #5
    What if a high voltage is applied, will it have any effect on lengthening the wavelength needed?
  7. Sep 28, 2009 #6
    Hi HMS I read many papers stating that the work function lower in the case it is exposed to vacuum and an electric field.
  8. Sep 28, 2009 #7
    I would expect heating it would help out. Heating up the material can cause thermionic emission without the incident light. Basically, the electrons would be excited thermally to higher states requiring less photonic energy.
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