9.1 The Nature of Magnetism
- Learn the origin of magnetism in materials.

9.2 Magnetic Poles
- Describe the magnetic poles and the interactions  between magnets.
- Calculate the magnetic field magnitude.

9.3 The Generator
- Explain how an electric generator works and how it differs from
  a motor.

9.4 The Transformer
- Describe a transformer and solve problems involving voltage,
  current and turn ratios.