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Homework Help: Speed of light question

  1. Dec 19, 2006 #1
    this isn't actually homework but i fear it is too simple to put in any of the other forums :redface:
    why is it that you can calculate the speed of light by (permettivity*permeability of free space)^-0.5
    i can't seem to find it in any of my textbooks, but my physics teacher told me it was a standard proof thing...
  2. jcsd
  3. Dec 19, 2006 #2
    you can derive it using maxwell's equations
  4. Dec 19, 2006 #3


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    Staff: Mentor

    More specifically, if you use Maxwell's equations to derive the wave equation for E or B, you get something that looks just like the standard differential wave equation, with [itex]1/\sqrt{\epsilon_0 \mu_0}[/itex] where the wave speed should be.
  5. Dec 19, 2006 #4
    is it something doable by an A level student? cos i've heard about maxwell's equations but it's not on the syllabus...
    also, what are E and B?
  6. Dec 19, 2006 #5
    E = electric field
    B = magnetic field

    how much calculus have you done??
  7. Dec 19, 2006 #6
    int. by parts, substitution, integrating trig, first order differential equations
  8. Dec 19, 2006 #7


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    Staff: Mentor

    Sounds like you have a lot of the background, as long as you've had some vectors mixed in with the calculus. I googled something like maxwell equations derivation wave equation, and got lots of good hits. Here's one of the first hits on the list:


    EDIT -- Also, if you have access to a technical library, just check out some of the books on Electromagnetics. Most will have the derivation.
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