|I was read that we have magnets N45 to 50,000x
more powerful than the earth. My question is if we
have magnetic fields so powerful then why is there
magnetic fields so small in comparison to the
earth's field which is huge but not so strong?
How strong is the magnetic force that holds atoms
together 00.03645 Gauss? Also I would like to try
to build a permanent magnet motor to power a
generator, is it possible? |
|Question Date: 2019-06-08|
The Earth's magnetic field is generated in a
different way from the magnetic field in the
permanent magnets we use on the surface. It is
generated by flowing currents of molten iron in
the outer shell of the core. This does not
create a very large magnetic field (around 25
gauss at the surface of the core), but because
the core is so massive, the weak field is very
large in space. Out here, at the surface, the
field strength is only 0.25 gauss to 0.65 gauss,
because we are so far away from the core where the
magnetism originates. A strong permanent magnet
like N45-grade supermagnets are made out of a
highly magnetic material called neodymium iron
boride. This materials is way more magnetic
than the iron in the Earth's core, and a small
supermagnet can easily generate fields up to
thousands of Gauss right next to them. However,
because the magnets are not very big (compared to
the Earth's core), that field is not very big
spatially, and decays within a few inches or feet.
So, Earth's field is a big, weak magnet and N45
magnets are strong, small magnets.
How strong is the magnetic force that
holds atoms together 00.03645 Gauss?
Atoms aren't really held together by magnetic
forces. Rather, the nuclei are held together by
the strong nuclear force, which is much
stronger than a magnetic force. The electrons are
held to the nucleus by electrostatic interactions,
which are also much stronger than the magnetic
forces inside of atoms.
Also I would like to try to build a
permanent magnet motor to power a generator, is it
I'm not sure I totally understand this question.
A generator and a permanent magnet motor are
basically the same thing. If you take a motor
and attach its leads to a voltmeter and then spin
its shaft, you will see a voltage. This is using a
magnet as a generator. You can build a motor or a
generator using a permanent magnet and some magnet
wire (which you will have to wind into coils).
However, if you try and use a motor to power a
generator. You will have to supply electricity to
make the motor turn, which in turn will turn the
shaft of the generator to make electricity. But,
since the motor and the generator are both less
than 100% efficient, you will always get less
energy out of the generator than you supplied to
Earth's magnetic field is weak because the
electromagnetic dynamo that generates the Earth's
magnetic field doesn't actually propagate that
much electrical current, which means that the
magnetic field created by said current is weaker
than with a magnet created specifically to be a
Magnetism does not hold atoms together. The
electrons in an atom are held together by
electromagnetic force, but the force consists of
quantum energy states referred to as
'orbitals'. A strong enough electrical field
will strip the electrons off of atoms (this is
what causes lightning), but I am not sure how the
dielectric constants of matter that determines the
voltage per unit distance required to create an
electric spark works at the quantum level.
I am not sure what the number 0.03645 Gauss refers
to, or what a "permanent magnet motor" means. If
you are trying to build a perpetual motion machine
(a machine that produces energy without consuming
some kind of potential energy), then that is
impossible, as it would violate both the first and
second laws of thermodynamics.
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