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Wave parameters

Waves have moving crests (or peaks) and troughs. A crest is the highest point the medium rises to and a trough is the lowest point the medium sinks to.

This graph shows a wave travelling from left to right. The horizontal axis (x-axis) shows the distance x  travelled by the wave. The vertical axis (y-axis) show how far (distance) the surface of the medium has been displaced from  its normal level.
  From the representation of the wave in the above figure we can define:

1- Wavelength:
The wavelength of a wave is the distance from one crest to another ( or from one trough to another).
science the wavelength is a distance, it is measured in meters, (m). 
Its symbol is 
 , The Greek letter 'Lambda'. 

2- Amplitude:

The amplitude of a wave is the maximum distance that the surface of the medium (ex: water)
is displaced from its undisturbed level - in other word the highest of the crest. The amplitude is a distance, measured by meter (m). Its symbol is A .

3- Frequency and period:


The frequency of a wave is the number of waves produced by a source each second. It is also the number of waves that pass a certain point each second. 

The unit of frequency is cycle/sec or  the hertz (Hz). It is common for kilohertz (kHz), megahertz (MHz) and gigahertz (GHz) to be used when waves have very high frequencies.

 For example, most people cannot hear a high-pitched sound above 20kHz, radio stations broadcast radio waves with frequencies of about 100MHz, while most wireless computer networks operate at 2.4GHz.

Period of a wave: For reading only

Is the time taken for one complete wave to pass a point. 

The period unit is T and measured in seconds (s).

 Frequency (f) and period (T) are related to each other, as waves with a short period have a high frequency .