AQA A Level Physics Waves with correct answers

Longitudinal wave Particle vibration is parallel to direction of wave propagation Examples of a longitudinal wave Sound waves, seismic p-waves 00:37 01:24 Transverse wave Particle vibration is perpendicular to direction of wave propagation Only transverse waves can be polarised Examples of a transverse wave Electromagnetic radiation, seismic s-waves Particle displacement The distance of a particle from its equilibrium position in given direction Amplitude the maximum displacement of a particle (wave) from its equilibrium (or rest) position Frequency Number of oscillations (of a particle) per second Time period The time for one complete oscillation Wavelength (for non stationary wave) Shortest distance between two points in phase wavelength for stationary wave Distance between alternate nodes or distance from peak to peak/ trough to trough Diffraction Spreading out of a wave (when it passes through a gap or past the edge of an object) Refraction Wave bends/changes direction when its speed changes 00:00 01:24 Polarisation (transverse) wave oscillation is in one plane Application of polarisation in sunglasses • Light reflected from surfaces is (weakly) polarised in one plane (horizontal) • Polaroid in sunglasses can be orientated to remove this reflected light • Reducing glare