Physics FAQ Physics Forums FAQ

  1. ZapperZ

    ZapperZ 30,166
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    This forum contains simple responses to the most frequently-asked questions in the Physics sub-forums. It is a continually evolving thread, and more FAQ's will be added.

    For more in-depth coverage of Physics FAQ's, refer to

    Please PM me all questions, comments, corrections, etc.



    List of questions covered in this FAQ:


    Light, Photons, and Relativity

    Is light a wave or a particle?

    Do Photons Move Slower in a Solid Medium?

    Do photons have mass?
    (Includes: But photons have energy. By E = mc2, doesn't this mean that they have a mass?)

    If photons don't have mass, why do their paths "bend" in a gravitational field?

    I've read that in relativity the concept of the rest frame of a photon doesn't make sense. Why is that?


    Quantum Physics (Excluding Light and Photons)

    Why don't electrons crash into the nucleus in atoms?

    Does the Heisenberg Uncertainty Principle imply energy nonconservation?



    What is Heat?
    (Includes definitions of internal energy, work, and heat)


    Classical (or Newtonian) Mechanics

    Why is acceleration due to gravity a constant?
    Last edited by a moderator: Jul 1, 2011
  2. jcsd
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