Why is the force pushing electrons downwards in this scenario?

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Discussion Overview

The discussion centers around the direction of the force acting on electrons in a magnetic field, specifically in the context of electromagnetic induction. Participants explore the application of the right-hand rule and its implications for the motion of charged particles within a metallic lattice.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant expresses confusion regarding the direction of the force on electrons, referencing an article that states the force pushes them downwards, contrary to their understanding based on the right-hand rule.
  • Another participant clarifies that the force on a charged particle is determined by the equation ##\mathbf{F} = q \mathbf{v} \times \mathbf{B}##, noting that the right-hand rule indicates the direction of the vector ##\mathbf{v} \times \mathbf{B}##, which points upwards in this scenario.
  • A later reply acknowledges the clarification and emphasizes that the right-hand rule indicates the direction of the vector rather than the force itself, while also correcting a notation error regarding the vector representation.

Areas of Agreement / Disagreement

Participants appear to agree on the application of the right-hand rule and the relationship between the velocity, magnetic field, and force. However, the initial confusion regarding the direction of the force indicates that there may still be some unresolved aspects of the discussion.

Contextual Notes

There is a potential misunderstanding regarding the interpretation of the right-hand rule and its application to negative charges, which may affect the clarity of the discussion.

Saracen Rue
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Hello Physics Forums users,

Thank you for taking the time to read my thread. I has just reading through this following article: http://www.sciencehq.com/physics/electromagnetic-induction.html when I came across this:
upload_2017-3-16_11-6-54.png

And became rather confused. The right hand rule dictates that in this scenario; positive particles moving towards the left through a magnetic field into the page should result in a force that acts upwards. Due to the fact that electrons are the only free-moving component inside a metallic lattice, they should be forced upwards. However, this article states that the force pushes them downwards. Any help with understanding what's happening here is much appreciated.

Again, thank you for your time :)
 
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Remember that ##\mathbf{F} = q \mathbf{v} \times \mathbf{B}##. By the right-hand rule, ##\mathbf{v} \times \mathbf{B}## is a vector that points up in this scenario, and since ##q## is negative (it is the charge of the electron), you know the rest.
 
Last edited:
Ah thank you very much, that makes a lot more sense now. The right hand rule isn't indicating the direction of the force but rather the direction of vector ##v*B##.

Again, thank you for your help! :)
 
Saracen Rue said:
Ah thank you very much, that makes a lot more sense now. The right hand rule isn't indicating the direction of the force but rather the direction of vector ##v*B##.

Again, thank you for your help! :)
You're welcome!

Just a clarification, the vector we're looking at is ##\mathbf{v} \times \mathbf{B}##. What you wrote, ##v*B##, seems like the product of their lengths.
 

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