Course:SCIE001/Physics/Reading Guides/Chapter 33

33.1 Magnetism

Magnetism is different than electricity. They have similar behaviour, but they're not the same. There are six key properties of magnets listed that you should probably read.

Monopoles and Dipoles

Unlike electricity, magnetism seems to only come in dipoles. In electricity a dipole is made of two opposite charges separated by a distance. In magnetism there is no fundamental charge, or monopole. There are only dipoles.

Fun Fact: The discovery of a magnetic monopole would give a natural reason for why electric charge is quantized (it only come in multiples of 1/3 e). This was discovered by Dirac. He looked at what would happen if we assumed magnetic monopoles existed. He proved that the product of the electric charge and the charge of the magnetic monopole would have to be an integer.

Compasses and Geomagnetism

Geographic North pole is in fact a magnetic South pole, and you should be able to reason why.

33.2 The Discovery of the Magnetic Field

Hans Christian Oersted discovered that electric current makes the magnetic field.

The Effect of a Current on a Compass

When the current flows, a magnetic field forms in the direction of the right hand rule, with the thumb being the direction of the current and the rest of the fingers being the direction of the magnetic field.

The Magnetic Field

Magnetic Field has a lot of similarities with the electric field. However, "N" pole is used instead of the "positive test charge."

Two Kinds of Magnetism?

33.1 discusses the magnetic field by the magnet, and 33.2 discusses the magnetic field by the current. They are essentially one kind of a magnetic field.