| Topic: |
Science > Physics |
| User: |
"" |
| Date: |
08 Apr 2007 09:05:53 AM |
| Object: |
Magnetism question |
If the electromagnetic force is mediated by photons, then does that
mean that magnets emit photons and/or electromagnetic radiation? Seems
unlikely to me, but if not then how is the force between a magnet and,
say, a piece of iron transmitted? If so then what wavelength are they?
Can anyone please help, because I am as confused as hell, and reading
various articles about magnetism has not helped one bit.
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| User: "Androcles" |
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| Title: Re: Magnetism question |
08 Apr 2007 10:03:48 AM |
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<matt271829-news@yahoo.co.uk> wrote in message =
news:1176041153.387757.321890@b75g2000hsg.googlegroups.com...
If the electromagnetic force is mediated by photons, then does that
mean that magnets emit photons and/or electromagnetic radiation?
Yes, *moving* magnets emit photons.
http://www.androcles01.pwp.blueyonder.co.uk/AC/spin.gif
Seems
unlikely to me,=20
I can't help what it "seems" to you, a photon is a finite energy =
transfer
across space.=20
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| User: "Kelvin" |
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| Title: Re: Magnetism question |
08 Apr 2007 11:00:50 AM |
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wrote:
If the electromagnetic force is mediated by photons, then does that
mean that magnets emit photons and/or electromagnetic radiation? Seems
unlikely to me, but if not then how is the force between a magnet and,
say, a piece of iron transmitted?
It's a static field not a wave so I imagine you "transmit" it by
moving the magnet but the effect of its moving field propagates
at the speed of light.
If so then what wavelength are they?
Can you create a radio wave by spinning a magnet?
Can anyone please help, because I am as confused as hell, and reading
various articles about magnetism has not helped one bit.
When I'm confused it's usually because I have opinions,
so I stopped doing that.
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| User: "Edward Green" |
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| Title: Re: Magnetism question |
08 Apr 2007 12:08:56 PM |
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On Apr 8, 12:00 pm, Kelvin <Kel...@geothermal.oops> wrote:
matt271829-n...@yahoo.co.uk wrote:
If the electromagnetic force is mediated by photons, then does that
mean that magnets emit photons and/or electromagnetic radiation? Seems
unlikely to me, but if not then how is the force between a magnet and,
say, a piece of iron transmitted?
It's a static field not a wave so I imagine you "transmit" it by
moving the magnet but the effect of its moving field propagates
at the speed of light.
Something a cognoscentum is sure to bring up is the difference between
so-called real and "virtual" photons; the latter, as far as I
understand, being a description applied to element of the mathematics
of QED which are suggestive of photons in situations where no right
thinking person would suppose there are any damn photons being
exchanged: like, f'rinstance, the interaction between a static magnet
and a piece of iron, or between two static charges. It probably does
absolutely no good at all to agonize over just how photonish virtual
photons are, without understanding the mathematical development being
described, which renders the words superfluous.
I hope to achieve this state of understanding in the next life, if I
am very good in this one.
If so then what wavelength are they?
Can you create a radio wave by spinning a magnet?
What is the sound of one hand clapping?
(Eh... sorry... just got carried away).
That's a good question, and I would think the answer is yes, unless
you are spinning the magnet around a symmetry axis of the field. A
time varying magnetic field begets a time varying electric field, and
that's how electromagnetic waves are born.
Can anyone please help, because I am as confused as hell, and reading
various articles about magnetism has not helped one bit.
When I'm confused it's usually because I have opinions,
so I stopped doing that.
Honest confusion is better than a fraudulent certainty.
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| User: "Kelvin" |
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| Title: Re: Magnetism question |
08 Apr 2007 04:27:09 PM |
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Edward Green wrote:
On Apr 8, 12:00 pm, Kelvin <Kel...@geothermal.oops> wrote:
matt271829-n...@yahoo.co.uk wrote:
If the electromagnetic force is mediated by photons, then does that
mean that magnets emit photons and/or electromagnetic radiation? Seems
unlikely to me, but if not then how is the force between a magnet and,
say, a piece of iron transmitted?
It's a static field not a wave so I imagine you "transmit" it by
moving the magnet but the effect of its moving field propagates
at the speed of light.
Something a cognoscentum is sure to bring up is the difference between
so-called real and "virtual" photons; the latter, as far as I
understand, being a description applied to element of the mathematics
of QED which are suggestive of photons in situations where no right
thinking person would suppose there are any damn photons being
exchanged: like, f'rinstance, the interaction between a static magnet
and a piece of iron, or between two static charges. It probably does
absolutely no good at all to agonize over just how photonish virtual
photons are, without understanding the mathematical development being
described, which renders the words superfluous.
'Virtual' anything sounds like an applied math fudge.
I think of math only as a tool for understanding physics.
Otherwise how can we tell coding tricks used in
computer simulations from something that would more
substantially increase our understanding?
The Lorentz contraction explanation of magnetism
kind of resembles the piezoelectric effect.
I hope to achieve this state of understanding in the next life, if I
am very good in this one.
If so then what wavelength are they?
Can you create a radio wave by spinning a magnet?
What is the sound of one hand clapping?
(Eh... sorry... just got carried away).
That's a good question, and I would think the answer is yes, unless
you are spinning the magnet around a symmetry axis of the field. A
time varying magnetic field begets a time varying electric field, and
that's how electromagnetic waves are born.
I'm going to quess no, you'll need the other hand.
I'd think there would have to be a charge lying around
somewhere close to make that time varing electric field.
Can anyone please help, because I am as confused as hell, and reading
various articles about magnetism has not helped one bit.
When I'm confused it's usually because I have opinions,
so I stopped doing that.
Honest confusion is better than a fraudulent certainty.
.
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| User: "Sam Wormley" |
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| Title: Re: Magnetism question |
08 Apr 2007 06:47:37 PM |
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wrote:
If the electromagnetic force is mediated by photons, then does that
mean that magnets emit photons and/or electromagnetic radiation? Seems
unlikely to me, but if not then how is the force between a magnet and,
say, a piece of iron transmitted? If so then what wavelength are they?
Can anyone please help, because I am as confused as hell, and reading
various articles about magnetism has not helped one bit.
The electromagnetic force *is* mediated by photons (virtual or
real) including forces associated with magnetic fields.
Some Frequently Asked Questions About Virtual Particles
http://math.ucr.edu/home/baez/physics/Quantum/virtual_particles.html
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| User: "" |
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| Title: Re: Magnetism question |
08 Apr 2007 07:25:48 PM |
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On Apr 9, 12:47 am, Sam Wormley <sworml...@mchsi.com> wrote:
matt271829-n...@yahoo.co.uk wrote:
If the electromagnetic force is mediated by photons, then does that
mean that magnets emit photons and/or electromagnetic radiation? Seems
unlikely to me, but if not then how is the force between a magnet and,
say, a piece of iron transmitted? If so then what wavelength are they?
Can anyone please help, because I am as confused as hell, and reading
various articles about magnetism has not helped one bit.
The electromagnetic force *is* mediated by photons (virtual or
real) including forces associated with magnetic fields.
Some Frequently Asked Questions About Virtual Particles
http://math.ucr.edu/home/baez/physics/Quantum/virtual_particles.html
Thanks for the link. To be honest this may be a little above my level,
but then I did ask the question!
This article seems to be talking about wavelike phenomena. I have a
layman's picture of electromagnetic radiation (such as light from a
light bulb) having a wavelike nature, but I have problems about
whether a static magnetic (or for that matter electric) field has a
wavelike nature. If I have a static magnet sitting on a desk doing
nothing then does the (electro)magnetic field "emanating" from it
actually consist of waves in the same way as the light emanating from
a lightbulb does? Does constantly "emitting" those waves require
energy, meaning that the magnet will gradually lose energy (and so,
presumably, its magnetism) over time? I think I am still missing
something here.
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| User: "Sam Wormley" |
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| Title: Re: Magnetism question |
08 Apr 2007 08:31:07 PM |
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wrote:
On Apr 9, 12:47 am, Sam Wormley <sworml...@mchsi.com> wrote:
matt271829-n...@yahoo.co.uk wrote:
If the electromagnetic force is mediated by photons, then does that
mean that magnets emit photons and/or electromagnetic radiation? Seems
unlikely to me, but if not then how is the force between a magnet and,
say, a piece of iron transmitted? If so then what wavelength are they?
Can anyone please help, because I am as confused as hell, and reading
various articles about magnetism has not helped one bit.
The electromagnetic force *is* mediated by photons (virtual or
real) including forces associated with magnetic fields.
Some Frequently Asked Questions About Virtual Particles
http://math.ucr.edu/home/baez/physics/Quantum/virtual_particles.html
Thanks for the link. To be honest this may be a little above my level,
but then I did ask the question!
This article seems to be talking about wavelike phenomena. I have a
layman's picture of electromagnetic radiation (such as light from a
light bulb) having a wavelike nature, but I have problems about
whether a static magnetic (or for that matter electric) field has a
wavelike nature. If I have a static magnet sitting on a desk doing
nothing then does the (electro)magnetic field "emanating" from it
actually consist of waves in the same way as the light emanating from
a lightbulb does? Does constantly "emitting" those waves require
energy, meaning that the magnet will gradually lose energy (and so,
presumably, its magnetism) over time? I think I am still missing
something here.
Energy [often kinetic] isn't "used up" but conserved.
Conservation of energy and momentum is required at every vertex of
a Feynman diagram. Lines entering or leaving the diagram represent
real particles and must have E^2 = p^2c^2 + m^2c^4 .
See: http://www2.slac.stanford.edu/vvc/theory/feynman.html
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| User: "" |
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| Title: Re: Magnetism question |
08 Apr 2007 09:20:39 PM |
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On Apr 8, 5:25 pm, wrote:
On Apr 9, 12:47 am, Sam Wormley <sworml...@mchsi.com> wrote:
wrote:
If the electromagnetic force is mediated by photons, then does that
mean that magnets emit photons and/or electromagnetic radiation? Seems
unlikely to me, but if not then how is the force between a magnet and,
say, a piece of iron transmitted? If so then what wavelength are they?
Can anyone please help, because I am as confused as hell, and reading
various articles about magnetism has not helped one bit.
The electromagnetic force *is* mediated by photons (virtual or
real) including forces associated with magnetic fields.
Some Frequently Asked Questions About Virtual Particles
http://math.ucr.edu/home/baez/physics/Quantum/virtual_particles.html
Thanks for the link. To be honest this may be a little above my level,
but then I did ask the question!
This article seems to be talking about wavelike phenomena. I have a
layman's picture of electromagnetic radiation (such as light from a
light bulb) having a wavelike nature, but I have problems about
whether a static magnetic (or for that matter electric) field has a
wavelike nature. If I have a static magnet sitting on a desk doing
nothing then does the (electro)magnetic field "emanating" from it
actually consist of waves in the same way as the light emanating from
a lightbulb does? Does constantly "emitting" those waves require
energy, meaning that the magnet will gradually lose energy (and so,
presumably, its magnetism) over time? I think I am still missing
something here.
It's all about the electrons and their state of motion.
In the lightbulb you have electrons flapping around because they're
hot. Because they're charged, they emit photons, the energy to make
which comes from the heat. Every photon emitted by the bulb is
evidence an electron just fell to a low-energy state, from which it
can be thermally excited to a higher one, then spit out a photon, and
so on.
In the "static magnet sitting on a desk doing nothing" you have
orbital electrons (more correctly, magnetic domains made up of groups
of atoms, some of whose orbital electrons are) mutually aligned so
their fields add producing the macroscopically observable magnetic
field. Since the electrons are bound in stable orbitals they aren't
radiating anything. The field isn't being "emanated", it's just a
direct consequence of angular motion of the electrons. And no, it
isn't losing its magnetism except for those times when a magnetic
domain flips over so its field subtracts from a neighboring one. The
condition of "magnetism" is an unstable state; it generally must be
induced and over time will decay to the "unmagnetized" state as heat
joggles the domains. Superconductors avoid this because they
effectively only have one domain.
Mark L. Fergerson
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| User: "Edward Green" |
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| Title: Re: Magnetism question |
08 Apr 2007 12:11:47 PM |
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On Apr 8, 10:05 am, wrote:
If the electromagnetic force is mediated by photons, then does that
mean that magnets emit photons and/or electromagnetic radiation? Seems
unlikely to me, but if not then how is the force between a magnet and,
say, a piece of iron transmitted? If so then what wavelength are they?
I'm going to take a wild guess, and say imaginary. Let's see what
happens...
Can anyone please help, because I am as confused as hell, and reading
various articles about magnetism has not helped one bit.
You should realize that the electromagnetic field can also be
described as a classical field, which doesn't give one figo about
photons.
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| User: "" |
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| Title: Re: Magnetism question |
08 Apr 2007 02:14:25 PM |
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On Apr 8, 6:11 pm, "Edward Green" <spamspamsp...@netzero.com> wrote:
On Apr 8, 10:05 am, wrote:
If the electromagnetic force is mediated by photons, then does that
mean that magnets emit photons and/or electromagnetic radiation? Seems
unlikely to me, but if not then how is the force between a magnet and,
say, a piece of iron transmitted? If so then what wavelength are they?
I'm going to take a wild guess, and say imaginary. Let's see what
happens...
Can anyone please help, because I am as confused as hell, and reading
various articles about magnetism has not helped one bit.
You should realize that the electromagnetic field can also be
described as a classical field, which doesn't give one figo about
photons.
OK, well suppose we forget about photons, real or virtual, for the
moment. Is it an electromagnetic field around a (static) magnet that
causes it to attract a piece of iron? Is it also an electromagnetic
field about a (static) charged particle that causes it to attract (or
repel) other charged particles? Is there a qualitative difference
between the two?
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| User: "Freiddie" |
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| Title: Re: Magnetism question |
08 Apr 2007 03:31:19 PM |
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Well, yes. A field is DEFINED as something that exerts forces at
varying positions (varying x,y,z values in classical/simplified
mathematical way). I can't say they are 100% the same, but they are
not separate things either. It's because magnetic fields can induce an
electric field and vice versa. So they are like very intimate. But
they have differences - you don't expect them to be identical things,
of course.
Freiddie
http://fei.yuanbw.googlepages.com/
http://freiddy.blogspot.com/
http://crazibe.blogspot.com/
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