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

Photoelectric current: why does it decrease?

  1. Mar 31, 2015 #1
    In my book it is stated.When you keep the intensity constant and decrease the wavelength the photoelectric current decreases but I can't understand why?

    I thought it would stay the same since photoelectric current depends on the intensity of photons as more number oh photons means more e- released
     
  2. jcsd
  3. Mar 31, 2015 #2
    Are you talking about stopping potentials experiments? As in when EM radiation falls on a plate A and a potential difference is applied across plates A and B such that B is more negative?
     
  4. Mar 31, 2015 #3
    Should that not be the other way around?

    The electrons are not just being released from the surface. The ones further inside need to have more energy to escape the surface. If the wavelength of light is shorter electrons from further inside will make it out.
     
  5. Mar 31, 2015 #4
    The experiment is you supply light (photons) on a metal surface to release e-
    then they said 240 nm wavelength of radiation gives Max Photoelectric current.After that they said Intensity is constant and wavelength is reduced causing the current to decrease but I simply can't understand why
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook