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Questions tagged [electromagnetism]

147 questions
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Moving carbon nanotube in a magnetic field

When a metal wire moves across a magnetic field, voltage is induced across it, which is equal to $BLV$, where $B$ is strength of magnetic field, $L$ is the length of wire and $V$ is its velocity. Will a carbon nanotube also exhibit this phenomenon?…
qwe
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How is it possible electromagnets keep a heavy maglev train levitating without forcing anything metallic to be flinged away?

I always wondered how it is possible to have electromagnets so strong that they keep a heavy maglev-train levitating without forcing anything metallic to be flinged away or to be pressed against the ceiling of the vehicle-cabin? And how come a…
t0bias
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Why is the current that can be drawn from an electric generator constant?

In an answer to this question, for a motor used as a generator, the following was said: The maximum current that can be drawn from a generator is generally a fixed value that is not determined by speed. What equation(s) show this?
Jodes
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Superconductor Magnetic Field Limit

Not sure if this is a question for the engineering or physics stack exchange: The current maximum magnetic field for a nonpulsed magnetic field is around 45 Tesla while pulsed is around 100 Tesla. I'm assuming the primary reason for the limitation…
dl19
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In induction heaters why do metal pieces levitate in center of radial axis?

In induction heaters metal seems to levitate in center of radial axis, as well as longitudinal axis (see video). Is by any chance the reason for that like in this schematic, that magnetic field lines of a metal rod, forming closed loops, move in…
Dino
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magnetic levitated tower - magnetic fields and tensile strengths of materials

I was considering a system made from a stack of electromagnetically levitated platforms and wondering how you would go about comparing its tensile (and or compressive) strength to that of a solid material. There is a similar question and answer here…
Bruce Adams
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Can you shape a magnet and how would it effect its field

Long story short im playing with mental designs of an electric motor and I'm not sure on some things regarding magmets/magnrtic materials and my designs are in flux do to these variables. I'm wondering one if you can put a "blade" along an auger…
damian ritter
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Determining the magnetic reluctance of a straight flux path

Currently I run into an issue understanding the following. The bottom part of this magnetic circuit is made from steel which has a finite relative permeability. However, the flux paths is made out of 3 parts, namely lt1, lt2 and lt3. How could I…
Kevin Laemers
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Diametrically magnetised ring magnet, opposite poles on the inside?

I am wondering about the magnetic field on the inside of hollow magnets. As an example, will use a ring magnet. In a diametrically magnetised ring magnet, does the magnet have the same pole on the inside and outside diameter, like this? Or, does it…
StatQ
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How much does human tissue attenuate radio frequency signal of a given frequency?

Attenuation of radio frequency (rf) signals in a medium depends upon medium characteristics and frequency of the signal. How much does human tissue attenuate rf signal of a given frequency?
pkm
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How powerful should a magnet be to be able to pick the cans from the floor?

I bought a 4 W Electromagnet to collect aluminium cans laying on the floor. A can weighs around 0.015 kg. I read aluminium is only paramagnetic. And playing manually with the current magnet, I cannot appreciate any force being exerted to the…
Pep
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DC Motor Powered Car

So I run an engineering class even though I mostly just do theory myself, so when it comes to actually building stuff I miss some basic ideas I should know. I am having them make a DC motor out of a battery, magnet wire, a magnet of some sort, and…
Patrick Flint
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Why isn't power going into my apparatus

I am using a LightingWill Waterproof IP67 LED Power Supply: https://www.amazon.ca/gp/product/B07T1WRQ4H/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1 to power a magnetohydrodynamic drive with a circuit diagram that looks like this: the solenoids…
Faito Dayo
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Is there an inward (radial) force acting on a magnet inside a magnet?

With a magnet inside another hollow magnet, for example an iron rod in a hollow cylinder, the iron bar placed inside the cylinder with poles attracted to opposite poles of cylinder (likes repel opposites attract), is there also a force along the…
Dino
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Are the magnetic field lines flowing from north to south _inside_ a bar magnet as well?

It seems based on the magnetic field of ring magnets like the magnetic field lines of a bar magnet actually runs from N to S also inside the magnet, yet schematic images tend to show the field lines running from N to S outside the magnet, then…
StatQ
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