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What is the magnitude of the Electric field inside a light wave?

  1. Nov 21, 2006 #1
    I know the magnitude varys a lot, but I am just looking for some basic intuitive idea of light. Is the magnitude of light from my computer screen on the order of 10^6 N/C or more like 10^-6 N/C?
  2. jcsd
  3. Nov 21, 2006 #2
    Nevermind, I finally found it in my gen phys 2 book derived from the Intensity. 1300 W/m^2 ~ 1000 N/C
  4. Nov 22, 2006 #3
    I think the figure you quoted is the value for the intensity of light from the sun at a distance of 1 AU. But I'm not sure if that includes the entire EM spectrum, or just heat and visible light.
  5. Nov 22, 2006 #4

    Claude Bile

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    Classically at least, the field can vary widely, a laser beam for example might have a huge E field (enough to induce air to ionise in some cases). The light from a star obviously has a much weaker E field. Note that the amplitude of the E field is related to the intensity of a light beam. To give you an idea in terms of numbers (in intensity), we can detect 10^-14 W/m^2 and produce 10^12 W/m^2 (as a conservative estimate), that's 26 orders of magnitude right there.

    Last edited: Nov 22, 2006
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