###### Properties of Waves

#### A Wave

Above is a displacement / distance graph showing a wave. It is labeled with some key terms

**Amplitude** is the height of the wave from 0 displacement (normal) to the peak, where the peak is the highest point. The **Wavelength** is the distance from the start to the second point the wave passes 0. i.e. a complete wave.

**Period**: if it was a displacement/time graph, the period would be equivalent to wavelength, so period is the time for the wavelength. The **frequency** is 1 / period and measured in Hz (1Hz = 1wave per second).

#### The Wave Equation

Have a look at the examples using this equation, below.

A loundspeaker reproduces a note of frequency 320Hz. It travels through the air with a speed of 340ms^{-1}.

*a)*What is the wavelength in air?

l = v/f

l = 340ms^{-1} / 320Hz

__l = 1.06m__

*b)* The sound passes through water where its wavelength is 4.5m.

Calculate the speed of sound in water

V = fl

V = 320Hz x 4.5m *(frequency doesn't change)*

__V = 1,440ms ^{-1}__

#### Types of Wave: Transverse or Longitudinal?

There are two basic types of wave. They are

**Transverse**

The oscillation/vibration is at right angles to the direction of travel. An example of transverse waves are
electromagnetic waves

**Longitudinal Wave**

The oscillations/vibrations are along the line of travel.

Are mechanical waves because it actually moves particles. E.g. sound waves.