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Dispersion

The Components of White Light

Light is an example of an electromagnetic wave. X-rays and radiowaves are other examples. The differences between these waves are due to their different wavelengths. X-rays have a shorter wavelength than light does, therefore, they have a higher frequency and are of higher energy. Radiowave have a longer wavelength and are lower frequncy and, hence lower energy.

White light is a combination of a spectrum of wavelengths. Each wavelength is a different colour. See below.

There are six main colours: red, orange, yellow, green, blue and violet. You may have heard that there are seven colours of the rainbow but there are really only six.

Note:

When all of the wavelengths between 780 nm and 390 nm enter our eyes in roughly equal intensity, we perceive white light. White light is the sum of all of the colours of a rainbow.

Splitting the Colours

When refraction occurs, light is bent according to an increase or decrease of speed. The magnitude of the change in speed determines the amount of bending that takes place. Violet light has a higher frequency and energy than red light. Hence violet light travels slightly faster than red light. The result of this difference is that when white light is refracted, the violet component is bent most and the red component is bent least. Prisms show this particularly well, see below.

The Components of White Light

Splitting the Colours

The Components of White Light

Splitting the Colours

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