AQA GCSE Physics

Revision Notes

6.1.2 Describing Wave Motion

Describing Wave Motion

  • When describing wave motion, there are several terms which are important to know, including:
    • Amplitude
    • Wavelength
    • Frequency
    • Period


  • Amplitude is defined as:

The distance from the undisturbed position to the peak or trough of a wave

  • It is given the symbol A and is measured in metres (m)
  • Amplitude is the maximum or minimum displacement from the undisturbed position


  • Wavelength is defined as

The distance from one point on the wave to the same point on the next wave.

  • In a transverse wave:
    • The wavelength can be measured from one peak to the next peak
  • In a longitudinal wave
    • The wavelength can be measured from the centre of one compression to the centre of the next
  • The wavelength is given the symbol λ (lambda) and is measured in metres (m)
  • The distance along a wave is typically put on the x-axis of a wave diagram

Amplitude and wavelength, downloadable AS & A Level Physics revision notes

Diagram showing the amplitude and wavelength of a wave


  • Frequency is defined as:

The number of waves passing a point in a second

  • Frequency is given the symbol f and is measured in Hertz (Hz)

Time Period

  • The time period of a wave is defined as:

The time taken for a single wave to pass a point

  • The time period is given the symbol T and is measured in seconds (s)

Frequency equation, downloadable AS & A Level Physics revision notes

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