Electron Model
Earl Palmer
have been following this news group for a couple of weeks now and have the
following questions.
1. What is the current model of the electron? What are it's components and
how can I visualize it?
2. Does the electron have a magnetic field?
3. Does the electron in orbit around the nucleus of an atom have the
properties of an electromagnetic filed?
4. Is there an analog in nature for something with only one charge like the
negative charge of the electron? In other words how can a free electron
have a negative charge without a positive charge?
5. Is the mass of an electron a real mass, or is it the E=mc^2 mass?
Enough stupid questions for now.
Thanks, Earl in Beautiful Seattle
Matthew Nobes
On Sat, 31 Jul 1999, Earl Palmer wrote:
> My knowledge of physics is based on college physics classes 40 years ago. I
> have been following this news group for a couple of weeks now and have the
> following questions.
>
> 1. What is the current model of the electron?
It's a point particle, with charge=1, spin=1/2 etc.
> What are it's components and how can I visualize it?
It has no known componants. And due to quantum mechanics its
rather hard to visualize this sort of thing. (You could try to think of
it as a little sphere (very,very small) which behaves accoring to rules
that are not given by classical mechanics).
> 2. Does the electron have a magnetic field?
That is somewhat of a tricky question. The short answer is no.
But that all depends on what you mean by "have". A moving electron will
_produce_ a magnetic field.
> 3. Does the electron in orbit around the nucleus of an atom have the
> properties of an electromagnetic filed?
I'm not entirely sure what you are getting at here. Again the
short answer is no.
> 4. Is there an analog in nature for something with only one charge like the
> negative charge of the electron?
A proton?
> In other words how can a free electron have a negative charge without a
> positive charge?
That's just the way things are. It is importent to point out
here, that if you do relativistic quantum mechanics (Dirac equation is the
word you want) you are _forced_ to introduce states exactly like the
electron only with one unit of positive charge. These are antielectrons
(=positrons).
> 5. Is the mass of an electron a real mass, or is it the E=mc^2 mass?
Again, a somewhat tricky question. The m in E=mc^{2} is the
_rest_ mass of the particle (which is what I think you mean by _real_
mass).
> Enough stupid questions for now.
Not stupid at all (but perhaps somewhat unclear). It definitely
helps a lot if you state how much physics background you have though.
> Thanks, Earl in Beautiful Seattle
Well, if it's half as sunny there as it is here in Vancouver then
beautiful is not the right word.
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Ian Bannister
<EarlP...@Seatac.net> wrote:
>
> My knowledge of physics is based on college physics classes 40 years ago.
> I
> have been following this news group for a couple of weeks now and have the
> following questions.
>
> and how can I visualize it?
Point particle theories end with the electron. It is fundamental and has no
structure. It is a point source of charge with a small mass.
>
> 2. Does the electron have a magnetic field?
It has a magnetic moment since it can spin align to a magnetic field.
>
> 3. Does the electron in orbit around the nucleus of an atom have the
> properties of an electromagnetic filed?
It has the properties of a charge distribution around the nucleus. The
electromagnetic field is between the nucleus and the electron.
>
> 4. Is there an analog in nature for something with only one charge like
> the
> negative charge of the electron? In other words how can a free electron
> have a negative charge without a positive charge?
I don't understand this. Free charges are OK as a particle property just as
a positive charge is.
> 5. Is the mass of an electron a real mass, or is it the E=mc^2 mass?
>
Since the origin of mass is not well understood it is difficult to answer
this. The origin of a protons mass may be said to be relativistic since it
is composed of fast moving particles. There is no similar mechanism to
derive the mass of something with no structure.
Elad Tsur
>My knowledge of physics is based on college physics classes 40 years ago. I
>have been following this news group for a couple of weeks now and have the
>following questions.
Hi,
I'll try to answer you briefly. In any case, the answers can be found in any
good introduction to modern physics book. Also have a look at the Particle
Data Group site at http://pdg.lbl.gov/ - and the Physics FAQ at
http://math.ucr.edu/home/baez/physics/faq.html .
>1. What is the current model of the electron? What are it's components and
>how can I visualize it?
As far as we know today, the electron is pointlike and has no components
(unlike the proton).
>
>2. Does the electron have a magnetic field?
Yes. The magnetic moment of the electron is both measured experimentally and
calculated from QED (Quantum Electro-Dynamics), and the two values agree
with amazing accuracy.
>3. Does the electron in orbit around the nucleus of an atom have the
>properties of an electromagnetic filed?
The electron is not "orbiting" the nucleus in a classical sense. This is
impossible, because classicaly it will lose energy due to radiation. This
was one of the reasons Quantum mechanics was invented. However, bound
electrons behave as expected from QED.
>4. Is there an analog in nature for something with only one charge like the
>negative charge of the electron? In other words how can a free electron
>have a negative charge without a positive charge?
Sure - there is no problem with a free charged particles. You can get free
protons (Hydrogen ions), alpha particles, positrons... What we don't (and
can't) see as free particles are quarks, but that's another story.
>5. Is the mass of an electron a real mass, or is it the E=mc^2 mass?
It is the rest mass (what you call "real"). Anyway, the realtivistic mass
(E=mc^2) isn't much used today, since it is simply the energy in different
units.
>Enough stupid questions for now.
>
>Thanks, Earl in Beautiful Seattle
--
Elad Tsur
http://lep1.tau.ac.il/elad/