Quick question on Faraday's law.

In summary, a student is studying for a physics final and is struggling with a problem involving a wire loop and induced current. They question whether there will be a change in flux and if the problem could have a simple answer. It is determined that there will be no net current flow in the wire loop, but charges will still be forced in the same direction. In a different scenario, there would be a separation of charges and the buildup of an electric field until the electric and magnetic forces are equal.
  • #1
15
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So I'm studying for my physics final, and I ran across a problem that is giving me a bit of trouble.

http://cyclotron.tamu.edu/dhy/sample_final_exam.pdf [Broken]

the question is 3b.

I'm thinking that the wire loop will have no induced current in it since there isn't a change in flux when you consider a loop rather than a bar, but it doesn't seem right that a 13 point problem would have such a simple answer.
 
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  • #2
cair0 said:
So I'm studying for my physics final, and I ran across a problem that is giving me a bit of trouble.

http://cyclotron.tamu.edu/dhy/sample_final_exam.pdf [Broken]

the question is 3b.

I'm thinking that the wire loop will have no induced current in it since there isn't a change in flux when you consider a loop rather than a bar, but it doesn't seem right that a 13 point problem would have such a simple answer.

I think you've got it. If you look at it from the point of view of charges moving with velocity v through a magntetic field, charges in both vertical parts of the loop will be forced in the same direction. There will be shift of charge until the electric force offsets the magnetic force, but no net current flow. Charges in the top and bottom of the loop just get pushed to the side of the wire.
 
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  • #3
Dan,

what happens in the case of Figure (a)? Is there a separation of charges, positive ones accumulating at the top of the stick, negative ones at the bottom?
 
  • #4
quasar987 said:
Dan,

what happens in the case of Figure (a)? Is there a separation of charges, positive ones accumulating at the top of the stick, negative ones at the bottom?

Yes, and the same thing would happen for the loop. Charge separates and builds up an electric field. There will be equilibrium when the electric force and the magnetic force are equal and opposite.
 

1. What is Faraday's law?

Faraday's law, also known as the law of electromagnetic induction, states that a changing magnetic field can induce an electric current in a conductor.

2. Who discovered Faraday's law?

Faraday's law was discovered by the English scientist Michael Faraday in the 1830s.

3. What is the mathematical equation for Faraday's law?

The mathematical equation for Faraday's law is: emf = -N (dΦ/dt), where emf is the electromotive force, N is the number of turns in the conductor, and dΦ/dt is the rate of change of magnetic flux through the conductor.

4. How is Faraday's law applied in everyday life?

Faraday's law is applied in many everyday devices, such as generators, electric motors, and transformers. It is also used in power plants to generate electricity.

5. What are some real-world examples of Faraday's law?

Some real-world examples of Faraday's law include the use of induction cooktops, electric toothbrushes, and wireless charging of electronic devices. It is also used in MRI machines to create images of the body's internal structures.

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