Why is the force pushing electrons downwards in this scenario?

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In summary, the conversation is about understanding the direction of the force in an electromagnetic induction scenario. The article states that the force pushes electrons downwards, which is confusing as the right hand rule suggests it should be upwards. However, it is clarified that the right hand rule indicates the direction of the vector ##v*B##, not the force itself. The force is determined by the product of the charge and the vector.
  • #1
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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  • #2
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.
 
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  • #3
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! :)
 
  • #4
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.
 

1. What is EMF?

EMF stands for electromagnetic force, which is a force created by the interaction between electric and magnetic fields. It is also known as electromotive force.

2. How is EMF induced in a wire?

EMF can be induced in a wire by moving the wire through a magnetic field or by changing the magnetic field around the wire. This movement or change in magnetic field creates a current in the wire, which generates an EMF.

3. What is the principle behind moving a wire to induce EMF?

According to Faraday's law of induction, a changing magnetic field will induce an electric field, which in turn causes a current to flow in a conductor. Therefore, by moving a wire in a magnetic field, we are changing the magnetic field, which induces an EMF in the wire.

4. What are some real-life applications of moving a wire to induce EMF?

Moving a wire to induce EMF is the principle behind the working of electric generators, which are used to convert mechanical energy into electrical energy. It is also used in transformers to change the voltage of an alternating current.

5. Are there any safety concerns when working with moving wires to induce EMF?

Yes, it is important to be cautious when working with moving wires to induce EMF as it involves working with electricity. Safety precautions such as wearing protective gear and following proper procedures should be followed to avoid any accidents or injuries.

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