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Does a photon have energy density?

  1. Jul 17, 2010 #1
    Does a photon have energy density??

    can anyone help me what a photon behaves when talking about energy density?
    it seems that photon just travel through time but not space ,or im wrong?
    can anyone help? thx so much~~
  2. jcsd
  3. Jul 17, 2010 #2
    Re: Does a photon have energy density??

    yes a photon has energy density.

    Don't understand the first part of your question: Are you sure you mean energy density??
    See here http://en.wikipedia.org/wiki/Energy_density#Energy_density_of_electric_and_magnetic_fields

    for the energy density of an electromagnetic field.

    Since a photon is a probability function and perhaps also viewed as a point particle, "energy density" doesn't have a lot of value ....No one knows the physical size of any elementary particles....it's "uncertain"....

    Have you thought about light (on form of photons) traveling from the sun to the earth??
    Light travels to us here on earth over a period of minutes at an observed velocity close to "c".
  4. Jul 17, 2010 #3
  5. Jul 17, 2010 #4
  6. Aug 17, 2010 #5
    Re: Does a photon have energy density??

    I am wondering how a point like particle can have a wavelength. Wavelength implies spatial extension.

    Best wishes

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