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

B About electrons and the photoelectric effect

  1. Jul 17, 2017 #1
    I understand that electrons can be released from a material, such as metal, through the photoelectric effect. I also understand that some of them might "re-attach" themselves to the metal. For practical uses, it sounds like the electrons would be re-captured in some way, but for the electrons that are cast away - how far away can they go? Do they just float around in space forever? Or can they attach to other things? If they do not attach to something else, can they "die," or are they converted to different forms of energy eventually?

    I am very much a beginner to physics, but I can't seem to find an explanation of this anywhere so would appreciate any help. Thank you!
  2. jcsd
  3. Jul 17, 2017 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor

    You need to figure out the rest of the setup.

    The standard photoelectric effect experiment has an anode to attract the emitted photoelectrons. So these electrons just simply do not "float" endlessly. It is how we could detect the photocurrent and thus, say that there is emitted electrons.

    If there is no anode source (such as in a photoemission experiment), then the electrons will simply go along the direction that they were emitted until they bump into something, usually the walls of the vacuum vessel. Most of the electrons are emitted with a net energy, so they already have a momentum in a particular direction. So again, they simply do not meander endlessly.

  4. Jul 19, 2017 #3
    That very much depends on the frequency provided by the source. The higher the frequency of the wave emitted, the more momentum the photo-electrons will have and thus will travel a longer distance (provided that it has not bumped into anything) than a photo-electron being emitted by a wave with the threshold frequency.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted