this post was submitted on 07 Aug 2023
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Science Memes

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482
Frequency Rule (feddit.de)
submitted 1 year ago by [email protected] to c/[email protected]
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[–] lowleveldata 1 points 1 year ago (2 children)

Does it tho? It's basically an electric generator

[–] [email protected] 16 points 1 year ago (3 children)

It wouldn't produce anything. For magnets to induce electricity they require a conductor and air isn't one, at least not a good enough one. Without electrical current, there's no voltage, nor constant or oscillating kind of current and therefore no radio frequencies. An electronic crystal and a handful of components could.

[–] [email protected] 7 points 1 year ago* (last edited 1 year ago) (2 children)

No. Electromagnetic radiation. It doesn't need a conductor. Think of it as a loop antenna except instead of a coil of wire generating the field a permanent magnet does.

An electric field is produced by any moving magnet, all a nearby conductor does is provides easily movable electrons that can flow in response to it.

[–] [email protected] 1 points 1 year ago (1 children)

So are you saying that a fidget spinner equipped with a couple of magnets and spun fast enough to generate that radio frequency can interfere with a purpose built radio broadcasting antenna set for the same (or resonant) frequency? In other terms, it will be able to radiate enough mV over the air to disrupt it?

[–] [email protected] 5 points 1 year ago

The fast enough part is key. To generate a signal on the AM broadcast band you would have to rotate it at 800 thousands rotations per second. As for being able to interfere, radio signals are often in the microvolt/m range by the time they reach the reciver, and a strong magnet can produce a few volts in a small (10-20 turns) coil just being moved by hand. If you somehow managed to get a magnet spining at the 1575 million rotations per second as in the meme (without it disintegrating on contact with air, or getting ripped apart, or turning the air to plasma), it would produce massive amounts of field, tens of thousands of volts per meter.

GPS signals are actually especially weak, as low as 0.3 uV/m.

[–] lowleveldata 4 points 1 year ago (1 children)

they require a conductor

Well I mean, he's holding it in his hand...

[–] [email protected] 2 points 1 year ago (1 children)

They mean a conducting medium like an electrolyte

[–] [email protected] 2 points 1 year ago (2 children)

Like Gatorade?

[–] [email protected] 3 points 1 year ago

It's got what rotating magnets crave.

[–] [email protected] 3 points 1 year ago

More like Brawndo. It's got what you crave.

[–] [email protected] 4 points 1 year ago (1 children)

Electricity isn't the same as electromagnetic radiation. A varying magnetic field induces a varying electric field which radiates into space as an EM wave. See Maxwell's equations.

[–] [email protected] 0 points 1 year ago

Please describe "as if I'm 5yo" how a radio broadcasting antenna works? Thanks! =)

[–] [email protected] 1 points 1 year ago* (last edited 1 year ago)

That's not how that works...

The magnets aren't being moved across conductors to induce currents.