| Topic: |
Science > Physics |
| User: |
"Iam anonimous" |
| Date: |
19 Sep 2006 01:56:51 AM |
| Object: |
Flux |
Hello,
I'm having some hard time understanding Electric flux and guass's law.
Can somone help me by explaining it in their own terms rather than
giving the usual "Follow the link......"?
Thank you,
Iam anonimous
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| User: "Sorcerer" |
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| Title: Re: Flux |
19 Sep 2006 06:18:20 AM |
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"Iam anonimous" <iam.anonimous@gmail.com> wrote in message
news:1158649011.466636.70780@k70g2000cwa.googlegroups.com...
| Hello,
|
| I'm having some hard time understanding Electric flux and guass's law.
| Can somone help me by explaining it in their own terms rather than
| giving the usual "Follow the link......"?
|
| Thank you,
| Iam anonimous
Follow the link.
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| User: "Brit" |
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| Title: Re: Flux |
19 Sep 2006 07:30:15 AM |
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Iam anonimous wrote:
Hello,
I'm having some hard time understanding Electric flux and guass's law.
Can somone help me by explaining it in their own terms rather than
giving the usual "Follow the link......"?
Thank you,
Iam anonimous
'Flux' is Latin for 'flow'. A static electric or magnetic field can be
envisioned as a space containing lines of force. Where the field is
strong the lines are close together and where they are further apart
the field is weaker.
A single charge sitting in an electric field feels a force, and the
direction of the force is along the force line it's sitting on.
So, these fields can be thought of (very crudely!) as 'force-flow'
fields - hence 'flux'.
Hope this helps a bit.
Cheers,
Pete
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| User: "Igor" |
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| Title: Re: Flux |
19 Sep 2006 10:29:10 AM |
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Iam anonimous wrote:
Hello,
I'm having some hard time understanding Electric flux and guass's law.
Can somone help me by explaining it in their own terms rather than
giving the usual "Follow the link......"?
Thank you,
Iam anonimous
Flux is defined as the integral of the component of the field normal to
the surface over the area of the surface, or Phi = Int ( E dot dA).
Gauss's Law says that the amount of charge contained within a closed
surface will be directly proportional to the flux across the closed
surface. If the surface is chosen with appropriate symmetries, the
integral doesn't even need to be evaluated to find E. A good example
is a point charge, having a purely radial field. A spherical surface
with the charge as the center has a constant field everywhere on the
surface and so the flux is simply the surface area of the sphere times
the field or 4pi r^2 E. This leads to the electrostatic field.
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| User: "Iam anonimous" |
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| Title: Re: Flux |
19 Sep 2006 10:55:16 AM |
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Thanks guys. I guess i'm more clear now.
Cheers,
Iam anonimous.
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| User: "Sue..." |
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| Title: Re: Flux |
19 Sep 2006 08:17:28 AM |
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Iam anonimous wrote:
Hello,
I'm having some hard time understanding Electric flux and guass's law.
Can somone help me by explaining it in their own terms rather than
giving the usual "Follow the link......"?
Thank you,
Iam anonimous
Think of one perforated sphere with smoke blowing
out of the holes and another perforated sphere
connnected to a vacuum cleaner.
When the spheres are close, more smoke follows
curved paths to move from one sphere to the other.
If you have followed the links then you found the pic.
What replaces the smoke to explain the Coulomb
force ?
Stuff! 99&44/100% pure unadulterated stuff. :o)
We know electrons and positrons only by what
we can measure. Anything more fundamental
other than mass and charge is just musings.
The flux lines are just mental aids to help us
extend an analogy.
You can also view elecrons as imaginary points
that we use in describing the motion of other
imaginary points. Often that description matches
phenomena we see on some other scale.
And just as often it seems completly absurd. So for
the moment, most theorists consider charges
fundamental and inexplicable on any smaller scale.
Sue...
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| User: "rds" |
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| Title: Re: Flux |
21 Sep 2006 08:04:26 AM |
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Sue... wrote:
The flux lines are just mental aids to help us
extend an analogy.
Magnetic Flux lines are real and can be seen and felt suing iron
filings or fero fluid.
http://www.teachersource.com/catalog/page/Electricity_Magnetism_Engines/Ferrofluids/
Sue...
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| User: "Greg Neill" |
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| Title: Re: Flux |
21 Sep 2006 09:09:42 AM |
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"rds" <rdschwarz61@yahoo.com> wrote in message
news:1158843866.653594.246950@h48g2000cwc.googlegroups.com...
Sue... wrote:
The flux lines are just mental aids to help us
extend an analogy.
Magnetic Flux lines are real and can be seen and felt suing iron
filings or fero fluid.
How do you know that the resulting pattern isn't
simply due to the flux spontaneously rearranging
the particles to form lower energy conduits for
the field? Do you imagine that the field strength
between the lines of particles is actually zero?
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| User: "RP" |
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| Title: Re: Flux |
21 Sep 2006 08:49:33 AM |
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rds wrote:
Sue... wrote:
The flux lines are just mental aids to help us
extend an analogy.
Magnetic Flux lines are real and can be seen and felt suing iron
filings or fero fluid.
http://www.teachersource.com/catalog/page/Electricity_Magnetism_Engines/Ferrofluids/
Sue...
Then why, when you remove the filings and sprinkle them again over the
surface, are the lines moved from their former positions? And why, if
the filings are made smaller are there more lines formed?
What is happening with the iron filings is that they are magnetized by
induction, all with the same polarity as their adjacent neighbors, and
will thus be attracted to other filings lying more or less along a line
corresponding to the direction of their own magnetic field, which field
is more or less homogeneous, i.e. a continuum. The number of lines
formed is thus a function of the average width of the filings and of
the surface density of the filings. Each of these filings repels the
filings lying to either side of them, and attracts those lying off to
either end. You can experiment with two bar magnets to see that this is
so.
The tendency is for two parallel bar magnets whose poles are
constrained to face in the same direction to shift in position either
foward or backward with respect to each other, so that they can join
end to end with each other. Given two infinitely long parallel bar
magnets they will simply repel each other. This is essential what
causes the marked open spaces between the lines of iron filings, that
is, they are constriained from shifing position along thier lengths,
and so they simply separate from each other as far as mechanical and
frictional limitations will allow. This is why the filings line up as
they do, and this is no indication that the field exists in the form of
lines of flux.
HTH
Richard Perry
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| User: "Sue..." |
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| Title: Re: Flux |
21 Sep 2006 09:12:40 AM |
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rds wrote:
Sue... wrote:
The flux lines are just mental aids to help us
extend an analogy.
Magnetic Flux lines are real and can be seen and felt suing iron
filings or fero fluid.
If they were real you could count them as well.
The word flux is used in preference to something like
thread, string or wire to denote a mathmatical
abstraction.
Flux is viewed just as we do a point or a line.
Infintessimally thin lines that can be infinte in
number don't exit so neither does a collection of them.
Electrons and positrons ~exist~ in a form that taxes
our everyday notions of matter and what is real and
reasonable arguments can be advanced for moving
the dividing line one way or the other. So unless you
are writing a Nobel class paper to explain pair creation
it is best to just accept the convention that any
particular discipline is using while keeping in mind
that fundamental particles aren't quite real anyway...
as we define *real* in our everyday macroatomic
experience.
Sue...
http://www.teachersource.com/catalog/page/Electricity_Magnetism_Engines/Ferrofluids/
Sue...
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| User: "rds" |
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| Title: Re: Flux |
21 Sep 2006 10:15:23 AM |
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Electrons and positrons ~exist~ in a form that taxes
our everyday notions of matter and what is real and
reasonable arguments can be advanced for moving
the dividing line one way or the other.
I agree with this, however I would say it this way:
Flux lines can be observed indirectly, and they produce demonstrable
effects, and so are real in that sense. For example you can oberve that
the field curves around a bar magnet. The curve (direction) is real and
you can feel it and see its effect
It is a line of force set up between two polarized fabrics of space.
The width of the lines depends on the width of the fabric peices, but
the path and the polarization points are real.
For example:
Charged particles--ions and electrons--can be trapped by the Earth's
magnetic field. A fast rotation (or "gyration") around magnetic field
lines, typically thousands of times each second.
ions are real and observable matter which can be seen rotationg aound
distinct magnetic lines of flux.
see:
http://www-istp.gsfc.nasa.gov/Education/wtrap1.html
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| User: "pom" |
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| Title: Re: Flux |
21 Sep 2006 12:06:49 PM |
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rds a écrit :
Electrons and positrons ~exist~ in a form that taxes
our everyday notions of matter and what is real and
reasonable arguments can be advanced for moving
the dividing line one way or the other.
I agree with this, however I would say it this way:
Flux lines can be observed indirectly, and they produce demonstrable
effects, and so are real in that sense. For example you can oberve that
the field curves around a bar magnet. The curve (direction) is real and
you can feel it and see its effect
It is a line of force set up between two polarized fabrics of space.
The width of the lines depends on the width of the fabric peices, but
the path and the polarization points are real.
For example:
Charged particles--ions and electrons--can be trapped by the Earth's
magnetic field. A fast rotation (or "gyration") around magnetic field
lines, typically thousands of times each second.
ions are real and observable matter which can be seen rotationg aound
distinct magnetic lines of flux.
see:
http://www-istp.gsfc.nasa.gov/Education/wtrap1.html
The "lines" that the iron filings form are just an experiment on
interaction of magnetizable form-anisotropic particles with a magnetic
field.
The latter does not consist of "lines" but is continuous. The particles
are discrete magnetic dipoles that try to arrange in the lowest enrgy
configuration possible.
If you repeat this experiment several times, you will observe that the
line system formed by the filings is never exactly the same. There is an
infinite number of ways to arrange the magnetized particles in a
configuration of minimum (may be local only) energy.
I suspect that by superposing an alternating field, they will arrange in
a still lower energy configuration (technique of simulated thermal
annealing)
You can look up "Bitter stripes" or "decoration"
Pom
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