# Electromagnets Repelling Metal

• Kalrag
In summary: This repulsion force slows the magnet down and causes it to "float."In summary, the statement that running electricity through a magnet will repel metal is not entirely true. While it is possible to use electromagnets to repel non-ferrous metal, it is not the electricity itself that causes the repulsion, but rather the changing magnetic fields created by the electricity. This effect is described by Lenz's Law, which states that an induced current will flow in a direction to oppose the change that caused it.
Kalrag
I have a small physics book that states that if you run electricity throught a magnet it will repel metal. I just want to know if this is true.

I'm pretty sure that is false.

Electromagnets can be used to launch non-ferrous metal rings. See here.

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If the word "magnet", in the OPs question, is changed to "wire" or "conductor", then the statement would be true. It's an effect described by Lenz's Law.

http://en.wikipedia.org/wiki/Lenz's_law

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Now say I did change the word magnet to "wire" or "conductor". Could you explain how that would work?

Kalrag said:
Now say I did change the word magnet to "wire" or "conductor". Could you explain how that would work?

Did you look at the links? In the case of the video link, when a changing current flows through the wire, it sets up a changing magnetic field around the wire. This changing magnetic field induces a current in the nearby metal plate, which in turn creates another magnetic field that opposes the magnetic field created by the current in the wire. Because the two fields oppose, there is a repusion force between the wire and the metal plate.

Here's another cool demonstration of Lenz's law:

Notice how the magnet appears to momentarily float before it touches the copper base. In this case, the magnet has a steady magnetic field around it. However, because the magnet is moving as it approaches the copper base, the magnetic field of the magnet cuts across the copper plate inducing a current in it, which in turn creates another magnetic field that apposes the magnetic field of the magnet.

## What is an electromagnet?

An electromagnet is a type of magnet that is created by passing an electric current through a wire. This current generates a magnetic field that can attract or repel other metals.

## How do electromagnets repel metal?

Electromagnets repel metal through the use of a magnetic field. When an electric current is passed through a wire, it creates a magnetic field. This magnetic field then interacts with the magnetic field of the metal, causing repulsion.

## What types of metals can be repelled by electromagnets?

Electromagnets can repel any type of metal that is capable of being magnetized, such as iron, nickel, and cobalt. However, the strength of the electromagnet and the distance between the magnet and the metal will also affect the level of repulsion.

## How can the strength of an electromagnet be increased?

The strength of an electromagnet can be increased by increasing the number of coils in the wire, increasing the electric current flowing through the wire, or using a core material with high magnetic permeability, such as iron. Additionally, the distance between the electromagnet and the metal can also affect the strength of the repulsion.

## Can the direction of the repulsion be changed?

Yes, the direction of the repulsion can be changed by reversing the direction of the electric current passing through the wire. This will change the direction of the magnetic field and thus, the direction of the repulsion.

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