Longitudinal and Transverse Waves & Polarisation | A-Level Physics

Can the same sine curve describe both a transverse wave and a longitudinal wave? The curve alone cannot tell you—the oscillations and direction of energy transfer do. This A-level Physics lesson explains longitudinal and transverse waves, compressions and rarefactions, polarisation, Polaroid filters and Malus's law. You will learn how to: • classify waves by comparing oscillation with energy transfer • distinguish a wave graph from the physical shape of a medium • explain transverse waves using strings and electromagnetic fields • explain longitudinal sound using compressions and rarefactions • locate compressions and rarefactions on a displacement–distance graph • use polarisation as evidence that light is transverse • predict transmission through parallel and crossed Polaroid filters • apply I = I₀cos²θ as a Cambridge International extension • explain receiving-aerial and microwave-grille orientations Key rule: transverse oscillations are perpendicular to energy transfer; longitudinal oscillations are parallel to it. Lesson notes: https://inkphysics.co.uk/physics/wave... AQA specification: https://www.aqa.org.uk/subjects/physi... Cambridge International 9702 syllabus: https://www.cambridgeinternational.or... Chapters: 00:00 Same curve, two wave types? 00:18 Transverse waves 00:38 Electromagnetic waves 00:52 Longitudinal waves and sound 01:19 The displacement graph of sound 01:35 Compressions and rarefactions 02:13 Wavelength and sign convention 02:30 The wave-classification rule 02:42 Polarisation and Polaroid filters 03:02 Analysers and crossed Polaroids 03:36 Malus's law 04:08 Aerials and microwave grilles 04:27 Summary Subscribe for clear, concise A-level Physics lessons from InkPhysics. InkPhysics is independent revision content and is not affiliated with or endorsed by any examination board. #ALevelPhysics #Waves #Polarisation