Question

Hi There, I'm trying to learn more about the electromagnetic field. In particular I want to understand how I can use electromagnetic to hold structure. A door holder for example.
I'm not a physics major.

Answer 1

An electromagnet is made up of a coil of wire which has to carry an electric current, wound round a piece of iron, which is a ferro magnet. When the coil has a current flowing in it, the coil AND the iron become MAGNETISED STRONGLY and will attract other bits of iron and quite a few other things too.
Holding a structure depends VERY MUCH on the structure. In a car breaking yard, the electromagnets which throw the cars around are very powerful AND heavy. It takes a very high current. On the other hand, a titchy EM can probably be much lighter - takes lower currents.
http://perendis.webs.com