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Q & A: Electromagnetism

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Most recent answer: 10/22/2007
Q:
what is electeromagnetism
- Anonymous
queens Ny US
A:
My dictionary says that electromagnetism is "the phenomena associated with electric and magnetic fields and their interactions with each other and with electric charges and currents". This is basically just a long way of saying that electricity and magnetism are very closely related.

A great example of this is an electromagnet. You can build one of these at home by wrapping a fine insulated electrical wire many times around a nail, and then hooking it up to a battery. The nail will be turned into a temporary magnet. The principle behind this says that magnetic fields are produced by moving electric charges (called currents). In this case, there is a current flowing in the wire wrapped around the nail, and it produces a magnetic field along the direction of the nail. The nail itself is not needed to produce this field, but helps to contain and guide the field so you can (for example) pick up some paper clips with it.

Going the other way, you can create an electrical current by using a changing magnetic field. You can show this using a small coil of electrical wire hooked up to a very small light. Take a bar magnet and move it back and forth through the middle of the coil. (It won't work if you just hold the magnet still, since it has to be a changing magnetic field.) You should be able to see the light turn on because of the current that is induced in the wire. This is the same principle that makes electric generators possible.

-Tamara

(published on 10/22/2007)

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