The amplitude of a wave is a measurement of the distance from the top of a crest through the centre line (the still position, zero-point, mid-point) to the bottom of a trough.
In the case of an electromagnetic wave, amplitude corresponds with the intensity of light and the brightness of colour perceived by an observer.
- When the amplitude of an electromagnetic wave of a specific wavelength increases so does the overall distance between the peak and the trough of the wave.
- The measurement taken between the topmost point on a wave (the peak) and the centre line of the wave is called peak amplitude.
- Amplitude is measured in metres (m).
- The greater the amplitude of a wave, the more energy it carries.
- When amplitude increases so does the perceived vividness of a colour.
- Whilst the perceived brightness of a colour depends on the amplitude of a light wave, brightness is also somewhat influenced by wavelength. So for example yellows tend to look brighter than reds or blues.
https://en.wikipedia.org/wiki/Amplitude