Can The Faraday Paradox Be Solved?

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I should note that Faraday's disk itself is an exception to Faraday's law. When the disc rotates there is an emf from v×B, but with no change in the linked flux.There are a few others as well, like when two metal plates with slightly curved edges are rocked in a uniform magnetic field, there can be a large change in the flux linkage without the generation of an emf. Also, another interesting point. Notice how when I moved the whole contraption with the multimeter and the red wire on the magnet, there was no induced voltage. That is because everything is moving, even the measurement reference frame. If I only moved the red wire and the magnet together but left the other wires on the table then I would still get a voltage. That means that when I set the magnet on the moving disk, if the measurement device were rotating with the disk then there would be no voltage induced. Here is a great paper that actually tests out spinning the closing circuit. www.nature.com/articles/s41598-022-21155-x. And a lot of people are getting upset about magnetic field lines in the comments. I didn't make up the concept of magnetic field lines, nor Faraday's paradox. This concept and Faraday's paradox have been discussed for over 200 years, lol.

Spinning the magnet and the disc together still produces a voltage because OTHER parts of the circuit are stationary. There is still relative motion between the magnet and the circuit, just not between the magnet and the disc specifically. If you put the entire apparatus on a turntable, then you will get no voltage, as expected. As for why the spinning magnet doesn't produce a voltage, actually it does -- but it produces the SAME voltage on both sides of the circuit. If you connected two multimeters to the circuit, one on each side, with a ground connection in the middle, you would see identical voltage readouts on both multimeters.

Here's the next experiment you need to do: The same spinning disk but your closing wires run parallel to the magnetic field (i.e. Straight up and down), so they don't cut through the field lines.

Only 60 seconds in and already understand how generators/motors work. 🎉 Phenomenal

I think the description that magnetic field lines is just a construct make the most sense to me. An electromagnetic field is literally just described with the polarity and strength of a section of the field, and any "lines" just outline areas where the strength is the same, kind of like a pressure or temperature map.

I tried this in college with two toroidal magnets out of speakers (same as you had with your drill) but I machined a brass disk mounted to a brass axle such that the two toroidal magnets were placed on either side of the disk and because the disk was only about an eighth of an inch thick, the natural magnetic attraction of the two magnets clamped and rotated with the disk. I then put a multimeter from a brush on the outside edge of the disk and the axle and noted that in either case (whether magnet was held stationary or allowed to spin with the disk) a voltage was developed. I asked my physics professor and we never figured out what was going on. He referenced a very old book where the author claimed that the resolution lie in something to do with relativity (not around during Faraday). But I honestly never understood it sufficiently. I do remember the author claiming that if two equally charged particles a distance x apart were stationary then the force of repulsion was purely electrostatic. But if you as the observer were moving relative to the two particles, then the observed force between them was then a combination of electrostatic and magnetic because the motion gave rise to magnetic field around the charged particles. I found your description excellent. Now subscribed.

The shot you use that shows the scientists talking about something was very helpful to illustrate the concept of scientists discussing science.

Please solve Fermi's Paradox next :)

Your disc magnet has north / south poles on it's faces, and the field lines are concentrated around the edge by the steel cup it's mounted in. When the aluminum disc is rotating under it. it's cutting through the field as it passes by the edge of the magnet. When the magnet is rotating, the edge field is equal all around, so it's not cutting through the conductor, and not generating voltage. If you had a magnet disc with north and south poles alternating around one face, it would work.

REALLY Really need more such videos, As a high school student, it's fascinating for me because I Have learnt about these topics in school and now I'm applying these concepts in this paradoxes which is very cool

It sounds really suspicious when the youtuber paid to promote a product says “it has been found that the optimal health benefits are found at 3x the government reccomendations”

The plane of rotation is orthogonal to the field. When the metal is rotating, it is moving at right angles to the field, whether the magnet rotates of not.

Dr Stone fans already knowing this information: 🤓

Now I understand, thank you for the demo. The circuit drags, then jumps, then drags again.

what if the closing wires are oriented differently and come from the bottum instead of from the side for example?

I think "cutting field lines" is a red herring. What induces a voltage is a change in flux through a closed circuit, whether the magnet producing that flux is rotating or not is irrelevant. Consider a single wire rotating from the axis. As it rotates past the brushes the enclosed area changes, and flux being field * area this results in the induced voltage. But this requires a finite width brush. In the limit of infinite wires and an infinitely thin brush you will still get a voltage but generate no current. To generate current you require a finite width brush.

@electroboom where you at? 👀

When you spin magnet above starionary circuit nothing should happen. Magnet rotates yes but the magnet field doesnt change. So both are basicly stationary then how there should be voltage if both are stationary? ---- this happen also when magnet is attached to disc... the field is stationary but circuit under it rotates thefore there should be voltage --- nothing confusing therd.

I have an answer now; the emf/voltage in the wire is generated by the electrons as we know. The electrons need to be moving in a magnetic field to cause them to side-deflect and the final voltage is the sum of all the deflection forces. Because of uniformity, the magnetic field of the disc is the same if it is moving or not.. this is like seeing a row of 11111 moving along and noticing no change. So when the disc magnet is rotated and the conductor(electron-carrying disc) is stationary, there will be no emf- as the electrons are not moving. When both the magnet and disc are rotating there will be emf as the electrons are moving- as they see a uniform magnetic field- whether the magnet is rotating or not. So if we now rotate the emf sensor with the rotating metal disc(as in my last month's comment) there will be an emf according to the above. The wires of the external circuit being stationary or not doesn't make a difference- contrary to what has been suggested by some books.