Dispersion of Light (Cambridge International IGCSE Science)

Dispersion of light

• The dispersion of light is illustrated by the refraction of white light by a glass prism

• White light contains the wavelengths 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 glass 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 light through a prism

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

The visible spectrum of light

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

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

• The seven different colours of visible light waves correspond to different wavelengths

• In order of longest wavelength and lowest frequency to shortest wavelength and highest frequency :

  • Red
  • Orange
  • Yellow
  • Green
  • Blue
  • Indigo
  • Violet

The dispersion of light creates the seven colours of the visible spectrum

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

Exam Hint To remember the colours of the visible spectrum you could remember either:

• The name “Roy G. Biv”
• Or the saying “Richard Of York Gave Battle In Vain”