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X-rays and transformer coils.

  1. Sep 12, 2012 #1
    The EM field of a magnet or electromagnet can be converted to electricity with the use of a transformer (coil). My question is... Does that hold up for the whole EM spectrum... IR through Gamma?
     
  2. jcsd
  3. Sep 12, 2012 #2

    mfb

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    You cannot convert "the field of a magnet/electromagnet to electricity" - in the way that afterwards the field would be gone.
    You can harvest energy from moving magnets, slowing them down in the process. Simple setups will give you alternating current, where the frequency is proportional to the (rotational) velocity of your moving objects, with a prefactor given by the setup itself.
    Rotations in useful setups are limited to ~10000 rotations per second, so you will not get any MHz-frequency from generators. And even that is far away from the frequency of infrared or even gamma radiation.
     
  4. Sep 12, 2012 #3
    Ok, I thought that I once saw a prof use a tesla coil, and a flourecent bulb to show that em fields were all around. Maybe I was mistaken.
     
  5. Sep 12, 2012 #4

    mfb

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    That is similar to a transformator - you use alternating current to generate an alternating field, and this can be used to light lamps.
     
  6. Sep 12, 2012 #5
    What rimmini seems to have been asking about is an antenna, or at least an antenna that takes the form of a coil. It takes some somewhat involved math to theoretically describe.

    Small antennas have been made that are efficient at absorbing visible light, although they don't look exactly like coils.
     
    Last edited: Sep 12, 2012
  7. Sep 12, 2012 #6

    sophiecentaur

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    For direct interaction, as with a radio antenna, the antenna would need to be a couple of hundred nanometers long - molecule sized. But the photon energy would make the situation different from what goes on in a wire antenna at RF.
     
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