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Question about electromagnetic waves

J

Jack

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
 
B

Bob Myers

Jack said:
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?

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.
 
A

Anna Banana

Jack said:
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

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
 
J

Jack

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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