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Questions about EM Amplitiude

  1. Jun 23, 2006 #1
    Hi, I have a question about electromagnetic amplitudes. we can easily find the wavelength of any EM, but how do we determine its amplitude? in terms of joules vs. length vs. frequency?
  2. jcsd
  3. Jun 23, 2006 #2
    I don't understand your question. How do you measure amplitude? or how do you calculate it given something else?
  4. Jun 23, 2006 #3


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    Staff Emeritus
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    The square of the amplitude [of the electric field carried by the wave] is proportional to the irradience (intensity) of the wave, which is the power per unit area and hence has SI units of watts per square meter (W.m-2)
  5. Jun 25, 2006 #4

    Claude Bile

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    The easiest way is to measure the power or irradiance and infer the amplitude from there, assuming of course that the wave is monochromatic, infinite etc. etc.

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