Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Photoelectric effect and mirrors

  1. Feb 5, 2004 #1
    This may seem like a stupid question, but i just cant get my head around it. Basically i was wondering why a mirror refless light. Of course the simple answer suggests that it just reflexs it back (the basic laws of optics). But then i was also thinking about the photoelectric effect and was wondering why that didnt occur.

    Surely the photons would hit the mirror and be absorbed causing the photoelectric effect. So i guess im wondering why they dont get absorbed? or do they? What acctully causes reflextion on a sub atomic level?

    Thanks for any response, my mind is in a state of self doubt and reality twisting.
  2. jcsd
  3. Feb 5, 2004 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    The photoelectric effect only occurs when photons of the correct energy are adsorbed by specific metals. Mirrors do not emit photoelectric effect electrons.

    The reflections in mirrors occur because the surface of the mirror is a conductive surface with a electron gas type material. There are many weakly bound electrons which are free to migrate due the electromagnetic energy of the incident photons. The currents generated by the photons essentially result in emitted photons which are identical to the incident photons.
  4. Feb 5, 2004 #3
    Thanks, i knew it had to have something to do with the photons exciting the electrons and in turn a photon being emmited - hense the fact i had my mind set on the photoelectric effect.

    My mind is at rest now :)
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook