## Summary

#### The nature of waves

- A wave is a disturbance in a medium.
- It carries energy from one point to another without transferring matter.
- There are two main types: Longitudinal and Transverse.
- Sound waves are an example of longitudinal waves.
- Typically, sound waves travel at about 340 meters per second in air at room temperature and pressure.

#### Ways of showing waves

We use three ways of representing the propagation of waves:

- Dots.
- Colour maps.
- Line graphs.

#### Wavelength-frequency relation

Frequency *f*, wavelength λ and wave velocity *v* are mathematically related by:

*v = f λ*

#### Point sources and inverse-square law

The energy carried by waves that radiate uniformly in all directions from a point source decay as the inverse of the square of the distance from the point source. This is known as the inverse square law.