Magnet vs CRT TV a.k.a question about magnetic poles of electrons

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Discussion Overview

The discussion revolves around the interaction between a neodymium magnet and a CRT TV, specifically focusing on the behavior of electrons emitted from the cathode and their response to magnetic fields. Participants explore the implications of magnetic poles on charged particles, the effects of magnetic fields on electron movement, and the complexities of CRT technology.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant describes an experiment where a magnet affects the display of a CRT TV, noting the appearance of dark and illuminated spots on the screen due to electron movement.
  • Another participant states that all moving charged particles are deflected by magnets, indicating that the interaction is not solely related to the intrinsic magnetic moment of the electrons.
  • A participant questions whether the behavior of magnetic poles can be interpreted as having positive and negative charges based on their effects on negative charges.
  • Another response clarifies that the magnetic force on a charged particle depends on its speed and direction, emphasizing that the poles of a magnet should not be thought of as having electric charges.
  • A warning is issued against attempting similar experiments with a TV, suggesting potential damage to the device.
  • One participant suggests that the magnet likely interferes with the internal workings of the TV, expressing skepticism about the initial explanation provided.

Areas of Agreement / Disagreement

Participants express differing views on the nature of magnetic interactions with charged particles, with no consensus reached on whether the poles of a magnet can be equated to positive and negative charges. The discussion remains unresolved regarding the specific effects observed in the CRT TV experiment.

Contextual Notes

Some assumptions about the behavior of electrons and magnetic fields are not fully explored, and the complexity of CRT technology is acknowledged but not detailed. There is also a lack of references to the video mentioned, which limits the ability to verify claims made in the discussion.

Dummienoob
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When watching some videos about neodymium magnets, I came upon a very interesting phenomenon. Namely, the maker of the video put a large magnet near an old CRT TV.

At first, a big black spot appeared on the screen. This means that the electrons were repelled from from the magnet and didn't hit the screen. After that, he turned the magnet around and approached the screen again. This time, the electrons rushed to the magnet and created one illuminated spot, leaving the other parts of the screen dark.

My question is, why are the magnetic poles of the electrons emerging from the cathode all lined up in the same direction and why don't they 'turn around'? When I approach 1 big magnet's south pole with some small magnets' south pole, the small magnets always turn around, exposing their north pole and are attracted to the big one instead of reataining the same position and being repelled.
 
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Yes, I know that moving charged particles are affected by magnetic fields. But that means that 1 pole of the magnet attracts negative charge and the other one repels it. From that can we derive that one pole of the magnet has + charge and the other one has - charge or not?
 
Dummienoob said:
Yes, I know that moving charged particles are affected by magnetic fields. But that means that 1 pole of the magnet attracts negative charge and the other one repels it. From that can we derive that one pole of the magnet has + charge and the other one has - charge or not?

Charged particles are affected by magnetic fields, but not the way that you're thinking. The magnetic force a charged particle experiences depends on the particle's speed and direction. There is no force at all if the particle is not moving; if it is moving the force is at right angles to the direction of movement. There's no arrangement of electrical charges that will produce these effects, so it doesn't work to think about the poles of a magnet as if they're charged.

The force on a particle with charge ##q## moving with velocity ##\vec{v}## in a magnetic field ##\vec{B}## is ##\vec{F}=q\vec{v}\times\vec{B}## where the ##\times## operation is the vector cross-product.

Google for "Lorentz force" for more information.
 
Heads up: Don't try this with a TV unless you want to ruin it.
 
The magnet is likely interfering with the internal workings of the TV... But, without the reference, it is not possible to be sure.
It is unlikely that the offered explanation re post no 1 is correct.
Please provide a link or a reference to the video.
 

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