why magnet only attract iron particles?

Asked by rkjsgr | 11th Sep, 2010, 12:00: AM

Expert Answer:

First of all, Magnets do not attract only iron. They attract a whole class of elements known as  ferromagnetic materials.   These include iron, nickel, cobalt, some alloys of rare earth metals, and some naturally occurring minerals such as lodestone.
Magnets work in the following way:
Magnets attract iron due to the influence of their magnetic field upon the iron. Before a piece of iron first enters the magnetic field of a magnet. the polarization of the iron's atoms is random. As it is exposed to the magnetic field, the atoms of the iron begin to align their electrons with the flow of the magnetic field, which makes the iron magnetized as well. This, in turn, creates an attraction between the two magnetized objects.
Why ferromagnetic materials only, and not others:
Actually Magnets attract all objects, but Something that is strongly attracted to a magnet is said to have a high permeability. Iron and steel are two examples of materials with very high permeability, and they are strongly attracted to magnets. Liquid oxygen is an example of something with a low permeability, and it is only weakly attracted to a magnetic field. Water has such a low permeability that it is actually repelled by magnetic fields. Everything has a measurable permeability: people, gases and even the vacuum of outer space.

In electromagnetism, permeability is the degree of magnetization of a material that responds linearly to an applied magnetic field.

Answered by  | 11th Sep, 2010, 07:35: PM

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