Key Points: 3. Waves: Paper 1: Physics A Level AQA

Displacement

The distance and direction of a particle from the equilibrium position.

Amplitude

Maximum displacement of a vibrating particle.

Wavelength

Shortest distance between two particles in phase.

Frequency

Number of wave cycles occurring each second.

Wave speed

Distance travelled by a wave each second.

Phase difference

Measured in degrees or radians, the amount by which one wave lags behind another wave.

Path difference

Measured in metres, the difference in the lengths of two waves.

Progressive

Waves whose oscillations travel and transfer energy.

Transverse

Waves whose oscillations are perpendicular to the direction of propagation of energy e.g. electromagnetic waves.

Longitudinal

Waves whose oscillations are parallel to the direction of energy transfer. They consist of compressions and rarefactions e.g. sound waves.