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Question about electromagnetic waves

Discussion in 'Electronic Basics' started by Jack, Mar 3, 2006.

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  1. Jack

    Jack Guest

    Hi,
    When electric and magnetic waves are 90 degrees to each other, if I
    rotate the source of the waves by 90 degrees, electric and magnetic
    waves would interfere each other?
    Also, I assume that general transmission waves are of high frequecies
    and each TV antenna would recept same frequency on the same channel, so
    they might interfere with each other
    And general human speech is of extremely low frequencies so that
    transmission waves are at least several Kilo hertz are common, as
    normal human won't generate that high frequencies?
    Thanks
    Jack
     
  2. Jack

    Jack Guest

    I also apply superimposition thorem here
    Thanks
    Jack
     
  3. Bob Myers

    Bob Myers Guest

    I'm sorry, but I have absolutely no idea what you're trying to
    ask in the above. I strongly suspect that no one else who might
    be able to provide information does, either. If you have access
    to a local group where you can ask these questions in your
    native language, you may get better results there.


    Bob M.
     
  4. Anna Banana

    Anna Banana Guest

    Hi Jack,
    I know what you're getting at, and I see your command of the
    language is fine for your question.
    In your model, it seems that you are referring to field waves, but those of
    a squiggly line on paper... meaning a planar sinusoid I would guess. These
    don't exist in nature, though it is possible to generate and filter light,
    an electromagnetic wave, in this form... but without the squiggly line
    cartoon in actuality, though maybe effect.
    Electric fields and magnetic fields cannot cancel each other out. An
    electromagnetic wave
    can cancel another electromagnetic wave however, but to recreate this in a
    lab setting at radio frequencies would I think mean setting up a phase
    difference just right with full cancellation taking place within some
    aperature over a 1/4 the wavelength in diameter. An electric field and
    magnetic field within a radio wave can be seen as creating each other in the
    cause an effect view, and don't exist independantly.
    If you drop a pebble in water, you get an circular radiation
    pattern. Radio waves propagate outwardly this way,
    and light nearly the same way... though it is often more elliptical as
    measured, in a quantum sense spherical is the fundamental pattern and
    ellipses are the enhancements from antennas or optics.

    What you say about TV antennas sounds like you've made some
    observations fiddling with them, and there seems to be a kernal of truth in
    your understanding already. As the wavefront crosses the rabbit ear
    antenna, the wavefront can be out of phase at the second ear, as it arrives
    later.. this can be calculated as radio waves .. even the squiggly line
    cartoon kind, move at 2/3 the speed of light, so the radio wavelength would
    have to be around 4 times
    the space between the antennas to notice some imperfect cancellation between
    the two rods as you move them around.

    Well, consider that humans emit light at 10uM. Thats a high
    frequency, and it's an electromagnetic wave... but it's probably not what
    you were thinking of... Synaptic electrical activity I would think happens
    at fairly high rates, and I would think there is electro-chemical activity
    happening at very high speeds on a molecular level. Radio waves should
    indeed be emitted but would require extremely sensitive means to detect.
    For sensitivity, right now we humans are up to detecting radio waves from
    interstellar gas molecules 1000 light years away... so spectral analysis of
    a human sounds within reach, but a tuner for the gal you fancy may be a far
    way off... depending on your creativity.

    Typically eeg signals go up to 20 Hz. A normal or abnormal human I
    think would have similar radiation properties, though people with limbs
    might appear to be better radiators. Rosicrucians and Jehova's witnesses
    would be indestinguishable (so much for my doorbell / zapper idea).

    Another thing to keep in mind is us organic creatures probably do have
    a regular upper frequency limit for most of what we could conceivably
    radiate without being struck by a high energy 'particle', and while true
    it's also true that us organic creatures will probably never have access to
    the full span of frequencies existing, as the wavelengths are too short to
    measure. Future versions of physics will have slants in time, twists in
    space, and things we cannot imagine... so everything is suspect until then.

    Anna
     
  5. Jack

    Jack Guest

    Hi Anna,
    Thanks for your help. I just need to read further in order to
    understand the concepts.
    I appreciate it. Thanks
    Jack
     
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