Dispersion of Light (Cambridge O Level Physics)

• 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

Dispersion of White Light through a Prism

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

• 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)

The Spectrum of Colours of Visible Light

The colours of the visible spectrum: red has the longest wavelength; violet has the shortest