Text of Chapter 36 Magnetism. The Big Idea A changing electric field makes a magnetic field. This means that...
The Big IdeaA changing electric field makes a magnetic field.
This means that a moving charge makes a magnetic field.James Maxwell
Some FactsWe use the letter B to represent the magnetic field.It is a vector field.It is measured in Teslas orWebers or Gauss. TeslaWeberGauss
Magnetic PolesTwo Poles: North and South.
Magnetic poles always exist in pairs.
Keep breaking a magnet in half and you will never isolate a single pole.
Magnetic FieldsCompare the magnetic field produced by a bar magnet and the electric field produced by two charges.Magnetic Field from a bar magnetElectric Field from two opposite charges
Magnetic Field Produced by a Current in a wire.Use the Right Hand Rule
With your right hand point your thumb towards the direction that the current flows.
As you curl your fingers, the magnetic field points the way your fingers do.
One more important FactA changing magnetic field will create an electric field.
When this electric field is created by a conductor, a current will flow through the conductor.The current in the conductor is said to be induced.
InductionUsing a changing magnetic field to induce a current is how all electricity is made.Nikola Tesla is THE man who created the AC generator. His device uses magnets to induce an alternating current in a wire.
Other source of magnetic FieldsSome material, by its nature, is magnetic.