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

What is a Photon?

  1. Mar 12, 2013 #1
    What is a photon?
    Does it have mass?(if no then why it has momentum)
    it travels with speed of light?
    Has it some wavelength associated with it,that can be calculated by De Broglie wave equation?
  2. jcsd
  3. Mar 12, 2013 #2


    User Avatar
    Gold Member

    https://www.physicsforums.com/blog.php?b=3588 [Broken]
    Last edited by a moderator: May 6, 2017
  4. Mar 13, 2013 #3
    A photon is a packet of Electromagnetic Energy. Quantized light energy.

    A photon doesn't have mass but it has energy which is why it has momentum. E=pc.

    It travels at the speed of light because it IS light. Photons are the particle aspect of light. Light does have a measurable wavelength obviously, hence the EM spectrum. To calculate its de broglie wavelength calculate λ=h/p, h is planks constant, p is momentum.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook