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Diffraction accompanied with photoelectric effect

  1. Mar 11, 2014 #1

    bgq

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    Hi,

    I have read that light could either behave as waves or particles but not both at the same time.

    What will happen if we perform the diffraction experiment, but replace the screen with a metal whose work function is small enough so electrons could be ejected from the metal? Do we see (using naked eye or any other device) the diffraction pattern, or photoelectric effect?

    Thanks in advance.
     
  2. jcsd
  3. Mar 11, 2014 #2

    ZapperZ

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    Not sure why this is an issue. The photons that hit the metal and didn't get through will be involved in the photoelectric effect, while the ones that do get through will be involved later at the screen to form the diffraction pattern. They are different photons involved in different phenomena.

    This doesn't prove anything.

    Zz.
     
  4. Mar 11, 2014 #3

    UltrafastPED

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    As I see it: you cannot construct an experiment which _simultaneously_ detects the wave and particle aspects of the photon. Nor of the electron.

    For some detailed analysis at an elementary level see Feynman's "Lectures on Physics", volume III, the first few chapters.
     
  5. Mar 11, 2014 #4

    Drakkith

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    I don't see how you can separate the wave and particle properties. A simple double slit experiment requires that both light and electrons behave in both ways. As a wave in order to get a diffraction pattern, and as a particle to be detected by the detectors.
     
  6. Mar 12, 2014 #5

    bgq

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    Actually, it is not my intention to show any issue, I am just looking for the expected result of the proposed experiment. As I understand from you reply, both diffraction and photoelectric effect occur as some photons participate in the diffraction phenomenon while the others participate in the photoelectric effect, but no photon participate in both of them. Is this true?
     
  7. Mar 12, 2014 #6

    ZapperZ

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    Well, think about it. Presumably, you know what a photoelectric effect is, don't you. Do you think that in the photoelectric effect, the photon "survived" after it has been absorbed by the metal and the photoelectron is ejected? Look at Einstein photoelectric effect equation. Don't you see a violation in the conservation of energy in that equation if that photon goes on to participate in the diffraction phenomenon?

    Zz.
     
  8. Mar 12, 2014 #7
    You observe both phenomena.

    They behave as a waves until they hit the detector where they behave as point particles, the distribution of which, forms the diffraction pattern.
     
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