Swinging a hanging copper ring with a bar magnet

In summary, the ring will move back and forth in direction normal to the plane of the page as long as the magnet is moving along the normal direction too and of course inside the area of the ring.
  • #1
versine
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Homework Statement
Figure 34-26 shows a copper ring that is hung from a ceiling by two threads. Describe in detail how you might most effectively use a bar magnet to get this ring to swing back and forth.
Relevant Equations
Faraday's law
Force on current carrying wire
1627185878414.png

I thought of few scenarios and they ended up as follows:
The ring must have an induced current. Due to the symmetry of the ring, if one part of the ring feels a force, the part of the ring radially opposite this part will feel a force opposite in direction, since the current will be opposite in direction relative to the magnetic field. So they will either cancel out or cause the ring to spin, even if the magnetic field is moved to one side, making one side stronger.
 
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  • #2
No, the ring will not spin, in my opinion it will move back and forth (that is in direction normal to the plane of the page) as long as the magnet is moving along the normal direction too and of course inside the area of the ring.
 
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  • #3
Delta2 said:
No, the ring will not spin, in my opinion it will move back and forth (that is in direction normal to the plane of the page) as long as the magnet is moving along the normal direction too and of course inside the area of the ring.
In that case won't everything cancel?
1627187006370.png
 
  • #4
versine said:
In that case won't everything cancel?
View attachment 286533
The magnetic field from a bar magnet isn't exactly as you put it in that picture. It has a component like this (a z- component) but it also has x and y components (xy is the plane of the page). It is the force due to the x and y components that will make the current loop swing back and forth.
 
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  • #5
Thanks, makes sense
 
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  • #6
I wonder if you get a better swinging motion of the ring if you move the bar magnet left to right and back across the face of it, or if you push the magnet in and out of the ring in the direction normal to the page...
 
  • #7
All I could find is a piece of copper plumbing and a hard drive magnet.
copper.png
 

1. How does swinging a hanging copper ring with a bar magnet create electricity?

Swinging a hanging copper ring with a bar magnet creates electricity through the process of electromagnetic induction. When the magnet moves through the ring, it creates a changing magnetic field. This changing magnetic field induces a current in the copper ring, resulting in the production of electricity.

2. What is the purpose of using a copper ring in this experiment?

The copper ring is used because it is a good conductor of electricity. When the magnet moves through the ring, it induces a current due to the movement of the electrons in the copper atoms. This current can then be harnessed and used to power devices.

3. How does the strength of the magnet affect the amount of electricity produced?

The strength of the magnet does affect the amount of electricity produced. A stronger magnet will create a stronger magnetic field, resulting in a larger current being induced in the copper ring. However, there is a limit to how much electricity can be produced, as the resistance of the copper ring will also play a role in the amount of current that can be generated.

4. Can any type of metal be used in place of copper for this experiment?

No, not all metals can be used in place of copper for this experiment. Copper is a good conductor of electricity and is also non-magnetic, making it the ideal choice for this experiment. Using a magnetic metal, such as iron, would not produce the same results as the magnetic field would not be able to induce a current in the metal.

5. Is there a limit to how long the copper ring can continue to produce electricity?

There is no limit to how long the copper ring can continue to produce electricity as long as the magnet is in motion. However, the amount of electricity produced may decrease over time due to factors such as the resistance of the copper ring and the strength of the magnet. Eventually, the magnet will also lose its magnetic properties and the experiment will no longer work.

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