Revision Notes

3.2.5 Dispersion of Light

What is Dispersion of Light?

  • When light enters a denser medium, such as glass, it slows down (refracts), which causes it to bend
  • Different colours, however, slow down by different amounts, which causes them to bend by different amounts
  • This effect is known as dispersion and can be used to separate white light into its individual colours

refraction-by-prism, IGCSE & GCSE Physics revision notesWhen white light is shone through a prism it is dispersed into its individual colours

  • The seven colours of the spectrum are:

Light Spectrum, IGCSE & GCSE Physics revision notes

Red, Orange, Yellow, Green, Blue, Indigo, Violet

  • You can remember these colours either by remember the name:
Roy G. Biv
  • Or by remembering the phrase:
Richard Of York Gave Battle In Vain
Extended Only

Light as a Wavelength

  • Light is a transverse wave
  • The different colours of light all have different wavelengths (and frequencies)
    • Red has the largest wavelength
    • Violet has the shortest wavelength
  • Light of a single wavelength (a single colour) is known as monochromatic

Author: Jenna

Jenna studied at Cardiff University before training to become a science teacher at the University of Bath specialising in Biology (although she loves teaching all three sciences at GCSE level!). Teaching is her passion, and with 10 years experience teaching across a wide range of specifications – from GCSE and A Level Biology in the UK to IGCSE and IB Biology internationally – she knows what is required to pass those Biology exams.

Join Save My Exams

Download all our Revision Notes as PDFs

Try a Free Sample of our revision notes as a printable PDF.

Join Now