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

What does light's frequency actually mean?

  1. Mar 7, 2005 #1
    Can a single photon have frequency?

    If a certain light is said to have a a frequency of, say, 500 units, what does that actually mean about how the individual photons act?
  2. jcsd
  3. Mar 8, 2005 #2
    It means each photon has energy:

    E = hf

    No, it does not make sense for a single photon to have a frequency.
  4. Mar 8, 2005 #3


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Yes a photon does have a frequency, determined by the energy, as given in the previous post. Not sure why the previous poster would think that in spite of the photon having energy it does not have a frequency.
  5. Mar 8, 2005 #4

    Claude Bile

    User Avatar
    Science Advisor

    Most photon/atom interctions are frequency-dependant. Things like refractive index and absorption vary considerably with frequency.

  6. Mar 9, 2005 #5
    I think what king is trying is ask is "why does a photon have a frequency?"
  7. Mar 9, 2005 #6

    It means it exhibits wavelike properties.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook