IGCSE §3: Waves · IGCSE
Transverse and Longitudinal Waves
Revision notes on Transverse and Longitudinal Waves for the OCR A-level Physics specification (H556). Free to read, with 4 practice questions in the app.
Transverse wave — the particles oscillate at right angles to the direction the wave travels.
Examples: all electromagnetic waves, water ripples, waves on a rope or spring shaken side to side, and S-waves from an earthquake.
Transverse waves have crests (highest points) and troughs (lowest points).
Longitudinal wave — the particles oscillate parallel to the direction the wave travels, along the same line.
Examples: sound in any medium, ultrasound, and P-waves from an earthquake.
Longitudinal waves have compressions — regions where the particles are bunched together and the pressure is higher — and rarefactions, where they are spread out and the pressure is lower. The wavelength is the distance from one compression to the next.
A slinky shows both. Flick one end sideways and a transverse pulse travels along it. Push and pull one end along its length and a longitudinal pulse of compressions travels along it instead.
The test that matters: ask which way the particles move compared with the direction of travel. At right angles, transverse. Along the same line, longitudinal.
Sound cannot travel through a vacuum. A longitudinal wave needs particles to compress and spread out, and a vacuum has none. Electromagnetic waves are transverse oscillations of electric and magnetic fields rather than of matter, so they cross empty space perfectly well — which is why we can see the Sun but not hear it.
Example: the bell-in-a-vacuum-jar demonstration. As the air is pumped out, the bell is still visibly striking but the sound fades to nothing. The light still reaches you; the sound has nothing left to travel through.
4 questions on Transverse and Longitudinal Waves
Reading is not revising. This topic has 4 questions in the app — multiple choice, calculations, and written answers marked against the mark scheme, point by point. Miss one and it comes back later with its options reshuffled, so you have to know it rather than remember where the answer sat.
- Every topic of Edexcel International GCSE Physics (4PH1)
- Flashcards and every equation, linked to the topic it comes from
- Full mock papers in the real paper structure
20 minutes a day is free. No card, nothing to cancel — and the paid version never renews itself either.
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