Electric currents produce magnetic fields and moving magnetic fields produce electric currents. This module looks that this property of electric and magnetic fields in detail. You will learn about the magnetic fields generated by a wire and a solenoid, then go on to look at motors generators and transformers.
Review of Magnetism
From work in lower school you should already be familiar with the basic properties of magnets. They are:
- Magnets strongly attract magnetic materials such as iron, steel, nickel, cobalt, and some alloys and ceramics.
- Magnets have two poles: a north and a south.
- Like poles repel, unlike poles attract.
Notice the similarity between magnetism and electricity. Electricity attracts neutral materials (recall a rubbed balloon picking up small bits of paper). Electricity comes in two forms:positive and negative. Like charges repel, unlike charges attract. Physicists long ago realised that these similarities were important. It is now realised that electricity and magnetism are closely related forces. They are really two different aspects of the same force! We call that force electromagnetism. This next section of the electricity module is probably the hardest. But it is also the most interesting. Work the problems in the text as you go along and you will be able to cope.