Editing Magnet (section)

== Electromagnets ==
{{Main|Electromagnet}}

An electromagnet, in its simplest form, is a wire that has been coiled into one or more loops, known as a [[solenoid]]. When electric current flows through the wire, a magnetic field is generated. It is concentrated near (and especially inside) the coil, and its field lines are very similar to those of a magnet. The orientation of this effective magnet is determined by the [[right hand rule]]. The magnetic moment and the magnetic field of the electromagnet are proportional to the number of loops of wire, to the cross-section of each loop, and to the current passing through the wire.<ref>{{cite book | title = Physics for Scientists and Engineers | first1 = Todd | last1 =  Ruskell | first2 = Paul A.  | last2 = Tipler | first3 = Gene | last3 = Mosca | edition = 6 | publisher = [[Palgrave Macmillan]] | year = 2007 | isbn = 978-1-4292-0410-1 }}</ref>

If the coil of wire is wrapped around a material with no special magnetic properties (e.g., cardboard), it will tend to generate a very weak field. However, if it is wrapped around a soft ferromagnetic material, such as an iron nail, then the net field produced can result in a several hundred- to thousandfold increase of field strength.

Uses for electromagnets include [[particle accelerator]]s, [[electric motor]]s, junkyard cranes, and [[magnetic resonance imaging]] machines. Some applications involve configurations more than a simple magnetic dipole; for example, [[quadrupole magnet|quadrupole]] and [[sextupole magnet]]s are used to [[strong focusing|focus]] [[particle beam]]s.