Parts of a wave

Waves are described using the following terms:

  • Rest position – the undisturbed position of particles when they are not vibrating.
  • Displacement – the distance that a certain point in the medium has moved from its rest position.
  • Peak – the highest point above the rest position.
  • Trough – the lowest point below the rest position.
  • Amplitude – the maximum displacement of a point of a wave from its rest position.
  • Wavelength – distance covered by a full cycle of the wave. Usually measured from peak to peak, or trough to trough.
  • Time period – the time taken for a full cycle of the wave. Usually measured from peak to peak, or trough to trough.
  • Frequency – the number of complete waves passing a point each second.
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Wavelength can be defined as “the distance between two adjacent points in a wave that move in phase (or in step)”. Frequency can be defined as “the number of cycles of a wave that occur in one second”.

Diagram of a wave

A diagram showing the different components of a wave, which include peaks, troughs, amplitude, wavelength and the rest position.