# What does it mean by Electromagnetism | phycic

### Starting off with the definition of a Magnetic material:Any material which has its atoms ordered such that it exhibits the properties of magnetism | phycic

Any metal can be turned into a magnet giving it the characteristics of:

Temporary Magnetism: Rub a metal on an already existing magnet in one direction, this process will cause the metal to polarize and inherent magnetic properties. But this will only last for a small while.

Permanent Magnetism: If a metal is permanently polarized then it will not lose its magnetic properties. The best way to make a strong magnet is by inducing a magnetic field using an electric current.

In order to tell the strength of a magnet the units “Weber” and “Maxwell” are used, these units are defined using the “magnetic flux”, Magnetic flux is the total number of magnetic lines passing through a unit area (denoted by Φ or ΦB).

1 Maxwell (Mx) = 1 magnetic line of force
1 Weber (Wb) = 10^8 Maxwell

You cannot tell the strength of a magnet just by the number of magnetic lines of force passing through it, you need to know the relative area of the surfaces in comparison. Simply put it, you need to know the flux density (B). And you need to know the angle which the surface makes with the lines of force, (the angle between the normal of a surface and the flux).

Φ=BA —-> NΦ= NBA (for more than one turn)
B= Φ/A —-> (Weber/ meter^2)

The flux density is measured using the unit “Tesla”

1 Tesla = 1 Weber/ meter^2
similarly 1 Gauss = 1 Mx/ cm^2

1 Wb/m^2 = (10^8)/(100^2)
= 10^4 Mx /cm^2
That means: 1 Tesla = 10^4 Gauss