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Electrodynamics related question

  1. Sep 26, 2010 #1

    fluidistic

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    I've "learned" how to make X-Rays with the Bremsstrahlung effect. That is, we accelerate electrons (that we get by a current passing through a resistance) through a difference of potential and we put a material (generally metallic) so that electrons get "decelerated" very quickly and they emit photons, X-rays.
    My question is: when we accelerate the electrons with the difference of potential, don't they radiate photons?
     
  2. jcsd
  3. Sep 26, 2010 #2
    For regular RF frequencies it is called a radio transmitter antenna. In this case the radio antenna (usually 1/2 or 1/4 wavelength long) radiates a coherent RF wave (photons) with wavelengths of a few centimeters to ~300 meters. Microwave antennas are slightly different in that the radio waves are often emitted directly from waveguides without physical antennas.

    Bob S
     
  4. Sep 26, 2010 #3

    Born2bwire

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    Yes, but the bandwidth of the emitted radiation is much lower than X-rays and the rate of emmission is lower due to the much slower acceleration when compared to the braking mechanism. You can actually calculate the power of the emited radiation using the Larmor formula. Jackson gives a detailed treatment of such problems in his textbook.
     
  5. Sep 27, 2010 #4

    fluidistic

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    Ok thank you guys, really awesome explanations. I get it.
     
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