7.2.1—Transverse and longitudinal waves
- Syllabus
- 9702–2028–2029
- Objective
- 7.2.1
- Level
- AS
Transverse and longitudinal waves differ by particle motion relative to propagation
In a transverse wave, particles oscillate perpendicular to propagation; in a longitudinal wave, they oscillate parallel, producing compressions and rarefactions.
Classify the wave from particle motion, not from whether it is visible or mechanical. Polarisation is possible only for transverse waves.
A rope pulse is transverse; sound in air is longitudinal because air pressure changes travel through compressions.
Longitudinal does not mean “slow”, and transverse does not mean “up-down” in every orientation.
ConceptA-Level CAIE Physics AS