Transverse & Longitudinal Waves
Section: Waves | Syllabus: Cambridge AS Level Physics 9702
Transverse Waves In transverse waves, particles vibrate perpendicular (at right angles) to the direction the wave travels. Transverse Wave A wave in which particles vibrate perpendicular to the direction of energy transfer.
Particle motion: Up and down (or side to side) Wave direction: Left to right (horizontal) Key features: Peaks (crests) and troughs Example: Shaking a rope up and down-the wave travels horizontally along the rope, but the rope moves up and down (perpendicular) Examples of Transverse Waves: Light waves (electromagnetic waves) Water waves (ripples on a pond) Waves on a string or rope Seismic S-waves (secondary earthquake waves) All electromagnetic radiation (radio, microwaves, infrared, visible light, UV, X-rays, gamma rays) Diagram Placeholder [Diagram showing a transverse wave with particles moving perpendicular to wave direction - to be added] Longitudinal Waves In longitudinal waves, particles vibrate parallel (along the same direction) to the direction the wave travels.
Longitudinal Wave A wave in which particles vibrate parallel to the direction of energy transfer. Particle motion: Back and forth (parallel) Wave direction: Same direction as particle motion Key features: Compressions and rarefactions Example: Pushing and pulling a slinky-the wave travels along the slinky, and the coils also move back and forth in the same direction Compression A region where particles are pushed close together, creating higher pressure.
Rarefaction A region where particles are spread apart, creating lower pressure. Examples of Longitudinal Waves: Sound waves (in air, liquids, and solids) Ultrasound waves Seismic P-waves (primary earthquake waves) Pressure waves in gases Diagram Placeholder [Diagram showing a longitudinal wave with compressions and rarefactions, particles moving parallel to wave direction - to be added] Transverse vs Longitudinal Waves Property Transverse Waves Longitudinal Waves Particle vibration Perpendicular to wave direction Parallel to wave direction Wave features Peaks (crests) and troughs Compressions and rarefactions Can travel through vacuum?
Yes (electromagnetic waves only) No (need particles to compress) Can be polarized? Yes No Main examples Light, water waves, waves on strings Sound, ultrasound, P-waves Memory Trick: Transverse = "T" for "Top and bottom" (particles move up and down) Longitudinal = "L" for "Length-wise" (particles move along the wave direction) Important Note About Water Waves: Water waves appear transverse when viewed from the side (particles move up and down), but technically they're a combination of both transverse and longitudinal motion.
For IGCSE purposes, treat them as transverse waves .
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