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Power irradiance

  1. Jul 3, 2015 #1
    1. The problem statement, all variables and given/known data
    30idtmc.jpg


    2. Relevant equations

    3. The attempt at a solution
    I found the expression for the magnetic field, and then the Poynting vector.
    2nu6e6u.jpg

    If i find the intensity, that's the same as finding the average value of the Poynting vector, and the cos^2 disappears... Can you tell me what to do next?
    Thank you.
     
  2. jcsd
  3. Jul 3, 2015 #2
    Bump Bump. Does anyone know what to do next?
     
  4. Jul 3, 2015 #3

    SammyS

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    Please observe the Forum Rule regarding bumping.

    Bumping
    Do not "bump" one of your threads to the top of a forum's thread list by posting a basically empty message to it, until at least 24 hours have passed since the latest post in the thread; and then do it only once per thread.​
     
  5. Jul 3, 2015 #4

    SammyS

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    What does the Poynting vector tell you about the wave's intensity? What are it's units?

    How is the speed of light, c, related to ε0 and μ0 ?
     
  6. Jul 4, 2015 #5
    I wasn't aware of that rule, thank you for pointing it out.
    The intensity is the mean value of the Poynting vector. The units of the Poynting vector are W.m^-2, the same for intensity..
    I can use the retation c=1/sqrt(ε0*μ0), and therefore reducing 1/cε0 = sqrt(ε0/μ0). What should i do next?

    Thanks for your reply.
     
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