Dispersion of Light (Cambridge (CIE) O Level Physics): Revision Note

White light is a mixture of all the colours of the spectrum

Each colour has a different wavelength (and frequency), making up a very narrow part of the electromagnetic spectrum

White light may be separated into all its colours by passing it through a prism

• This is done by refraction

• Violet light is refracted the most, whilst red light is refracted the least

• This splits up the colours to form a spectrum

This process is similar to how a rainbow is created

Visible light is defined as the range of wavelengths which are visible to humans

Visible light is the only part of the spectrum detectable by the human eye

• However, it only takes up 0.0035% of the whole electromagnetic spectrum

In the natural world, many animals, such as birds, bees and certain fish, are able to perceive beyond visible light and can see infra-red and UV wavelengths of light

The different colours of waves correspond to different wavelengths:

• Red has the longest wavelength (and the lowest frequency and energy)

• Violet has the shortest wavelength (and the highest frequency and energy)