# Magnetic Field Part II

A magnetic field can be formed by a magnetic material, but a magnetic field can also be formed by electric current flowing through a wire. This forms what we can call an electromagnet.

The way this works is: we take a battery and the wires attach to the positive and negative ends and that wire is wrapped around an iron bar like right there. It doesn’t necessarily have to be an iron bar, but it needs to be made of thermomagnetic material.

Mini-test: MAGNETIC FIELD PART II

Question 1: An electromagnet
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Question 2: A magnetic domain
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The transcript is for your convenience.
Here we have an electromagnet and so what happens here, is when the current is turned on there is a magnet, this becomes magnetic, but when the battery is turned off and the current is turned off, the magnetism is lost. The magnetism can be turned on and off. This has many practical implications in real life and so electromagnets are often used in our society.

Now a magnetic domain occurs when the magnetic fields of atoms are grouped and aligned and so these groups form what can be thought of as miniature magnets within a material. Here these groups, these magnetic fields of atoms that are now grouped and aligned are considered miniature magnets within a material.

This is what happens when an object like an iron temporarily magnetized, that right there could be an iron nail. Prior to magnetization, the organization of atoms and their various polarities are sometimes random with respect to where the north and south poles are pointing. But after magnetization, a significant percentage of the poles are lined up in one direction, which is what causes the magnetic force exerted by the material. The north and south poles were pointing all over the place, but now they’re all pointed in the same direction, which allows a magnetic field to now be in place.