Questions tagged [electromagnetism]
122 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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Is there any material that blocks a static magnetic field?
Is there any material that blocks a static magnetic field? So that if I put it between a magnet and a piece of metal, they won't interact with each other?
ergon
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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?
CL22
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Can a Foucault's current brake be used on the rails themselves to brake trains?
Your typical Foucault's current brakes operate on a disk, which is placed in an electromagnetic field in order to transform kinetic energy into heat without friction. The problem is that the disk still overheats, just like an usual disk brake. In…
Bregalad
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Quantifying Static Electricity Hazard with High Explosives
In the making of firework explosives, the explosive mixtures are handled with great care to avoid static electricity induced detonation of the explosives. Is it a good idea that they store the explosives in a plastic container - isn't there a risk…
Hypnos Stratagem
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Magnetic decoupling torque
I have a system consisting of 4 magnets rotating at speeds between 200 and 6,000rpm, which are facing 4 other magnets with a 0.5mm gap between the two sets. The set-up looks like this:
Both sets of magnets have their noth pole facing out so that…
am304
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Magnetic levitation
I am currently considering turning my fascination with magnets into a diy activity.
How feasible is it for a hobbyist to construct a working model of a maglev device?
I'm looking to build something really small for now,just a demonstrative…
Ibrahim
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3
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How do old wind turbine towers pickup magnetism overtime?
I was conducting some robotics tests on a old wind turbine today, and noticed strong magnetic fields around the steel tower. This magnetic field does not exist on other modern wind turbines at the same site. I am completely baffled by this, so I’m…
Anshuo Liu
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What is the material requirement for Van der Graff generator sphere?
I would like to make a Van der Graff generator for my science fair project out of aluminized mylar. Do you think this might be feasable or do I need to use thick stainless steel ball? Is there some sort of charge or conductivity limit that I need to…
user2820052
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Dynamic magnetic field Vs electronics
It seems dynamic magnetic field may damages electronics components like diode, transistor etc, probably via electromagnetic induction. How much strength and what frequency magnetic field is dangerous? Surprisingly there is hardly any info on…
pkjhgy
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3
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How to split mercury with a magnetic force?
Do you think, one could split a mercury drop into two drops with the magnetic force? Mercury is a liquid metal, hence if I put a current through it, it will become a electromagnet (a wire with a current induces a magnetic field).
If I then place…
henry
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How to make the magnetic field intensity from a DC electromagnet bigger without changing its current, number of turns, or geometry?
I'm currently doing a project on magnetic haptic feedback using DC electromagnet. The principle of my haptic feedback system is very simple (figure shown below):
A permanent magnet is stuck to the user's finger (It doesn't necessarily have to be…
NakedRaccoon
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Do infrared heaters have a special blackbody radiation specturm?
There are many infrared heaters on the market, that I would put in 3 categories, filament in quartz tube, filament in ceramic, and carbon film (for flat panel heaters).
They all claim to be "infrared heaters" however, as far as I can tell, they all…
Manu de Hanoi
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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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