# Dropping two magnets through a copper tube

• Xiao10
In summary, the conversation discusses the effects of two bar magnets being dropped through a copper tube at the same time, with the same pole facing each other, and whether they would fall faster or slower than if only one magnet was dropped. The consensus is that the magnets would fall slightly faster due to the decreased field density between them, resulting in a weaker effect of eddy currents. However, the experiment was unreliable and may need to be repeated with better equipment.
Xiao10
Hi,

In class we were discussing the effects of a two bar magnets being dropped through a copper tube at around the same time, with the same pole facing towards each other, so that the two magnets repel - would the magnets fall through the tube faster or slower than if only one was dropped through?

At a guess I think the magnets will fall slightly faster, the field density between the two magnets should be decreased as the lines are pointing in opposite directions, this means that flux is cut at a lesser rate so the strength of the eddy currents should be decreased.

(The experiment was attempted once, and the effect was seen to be small, however it was quite a unreliable set-up).

I think the lower one would fall quicker, the upper one would fall slower, as both are repelling and therefore accelerating away from each other ;).

Considering eddy currents: I don't know the relative sizes of your setup parts. However, the field lines are mainly parallel to the direction of movement, right? In that case, I wouldn't expect a large effect from eddy currents.

Thanks, that makes sense, will try the experiment again if time and equipment allowsl

## 1. How does dropping two magnets through a copper tube create an electric current?

When the magnets are dropped through the copper tube, they create a changing magnetic field. This changing magnetic field induces an electric current in the copper tube, according to Faraday's Law of Induction.

## 2. What factors affect the strength of the electric current produced?

The strength of the electric current produced by dropping magnets through a copper tube depends on the strength of the magnetic field, the speed at which the magnets are dropped, and the material and dimensions of the copper tube.

## 3. Can any type of magnet be used for this experiment?

Yes, any type of magnet can be used as long as it has a strong enough magnetic field to induce an electric current in the copper tube.

## 4. How can this experiment be used to demonstrate electromagnetic induction?

By dropping the magnets through the copper tube, the changing magnetic field and resulting electric current demonstrate the process of electromagnetic induction, which is the production of an electric current by a changing magnetic field.

## 5. Is the electric current created by this experiment strong enough to power anything?

The electric current produced by dropping magnets through a copper tube is typically very small and not strong enough to power anything. This experiment is more of a demonstration of electromagnetic induction rather than a practical source of electricity.

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