CIE AS Level Physics: Transverse and Longitudinal Waves

Transverse waves

A wave in which the particles oscillate perpendicular to the direction of motion and energy transfer.

Longitudinal waves

A wave in which the particles oscillate parallel to the direction of motion and energy transfer.

Transverse wave examples

Electromagnetic waves e.g. radio, visible light, UV; Vibrations on a guitar string.

Longitudinal wave examples

Sound waves.

Rarefaction

An area of low pressure, with the particles being further apart from each other.

Compression

An area of high pressure, with the particles being closer to each other.

Propagation of transverse waves

Transverse waves do not need particles to propagate, and so they can travel through a vacuum.

Propagation of longitudinal waves

Longitudinal waves need particles to propagate, and so they cannot travel through a vacuum.

Polarisation of transverse waves

Transverse waves can be polarised.

Polarisation of longitudinal waves

Longitudinal waves cannot be polarised.

Wavelength in longitudinal waves

The diagram shows the equivalent of a wavelength on a longitudinal wave.

Displacement in transverse waves

Displacement is perpendicular to the direction of propagation (energy transfer).

Displacement in longitudinal waves

Displacement is parallel to the direction of propagation (energy transfer).

Wave period and frequency

The wave has a period of 1.0 s, a frequency of 1.0 Hz and could be either transverse or longitudinal.

Amplitude of a wave

The wave has an amplitude of 2 cm and could be either transverse or longitudinal.

Period of a wave

The wave has a period of 4 s.

Graph interpretation

The x-axis of this graph is time, so all that can be inferred is that the particle is displaced periodically.

Wave type determination

Both transverse and longitudinal waves can look like transverse waves when plotted on a graph.