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Do the photons have mass?

  1. Aug 20, 2012 #1
    do the photons have mas???or just the momentum???or both??
  2. jcsd
  3. Aug 20, 2012 #2


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    Re: photons

    Photons have zero rest mass m=0. So the equation

    E² = (mc²)² + (pc)²

    relating energy E, rest mass m and momentum p reduces to

    E = pc

    Using Planck's constant h the energy E can be written in terms of frequency f as

    E = hf
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