• The principle of superposition states that?when two or more waves with the same frequency travelling in opposite directions overlap, the resultant displacement is the sum of displacements of each wave
• This principle describes how waves which meet at a point in space interact
• When two waves with the same frequency and amplitude arrive at a point, they superpose either:
  • in?phase, causing?constructive interference.?The peaks and troughs line up on both waves. The resultant wave has double the amplitude
  • or, in?anti-phase, causing?destructive interference.?The peaks on one wave line up with the troughs of the other. The resultant wave has no amplitude

Waves in superposition can undergo constructive or destructive interference

• The principle of superposition applies to all types of waves i.e. transverse and longitudinal