Topic 4.4: Wave Characteristics Flashcards
• 4.4.1: Describe a wave pulse and a continuous progressive (travelling) wave
o OSCILLATIONS: A repeated back and forth motion.
o CYCLE: One complete oscillation.
o TRAVELLING WAVE: A disturbance moving from a source and transferring energy from one point to another.
• 4.4.3: Describe and give examples of transverse
o Transverse Waves: Where the disturbance is at right angles to the direction of travel of the wave.
Cannot be propagated in gases
Examples:
• Light waves
4.4.3: Describe and give examples of longitudinal waves
o Longitudinal Waves: Where the disturbance is parallel to the direction of travel of the wave.
Examples:
• Sound waves
Define wavefronts
o WAVEFRONT: A line of surface which joins all points which have the same displacement at the same moment (they are all in phase).
Define rays
o RAY: A line at right angles to the wavefronts which shows the direction of energy travel of the wave.
Describe crest and trough
o CREST AND TROUGH: For a transverse water wave, the maximum and minimum displacements.
Describe compression and rarefraction
o COMPRESSION AND RAREFACTION: For a longitudinal wave, points of maximum and minimum density of the medium.
Define displacement
o DISPLACEMENT: The distance of the disturbance measured from its equilibrium position.
Define amplitude
o AMPLITUDE: The maximum displacement from the equilibrium position
Define frequency
o FREQUENCY: The number of oscillations completed in a second (hertz)
Define period
o PERIOD: The time taken for an oscillation. f=1/T; T=1/f
Define wavelength
o WAVELENGTH: The distance between consecutive points on the wave which are in step (ie in phase)
Define wave speed
o WAVE SPEED: The speed of travel of the energy of the wave.
Define intensity
o INTENSITY: The rate of flow of energy through unit area perpendicular to the direction of travel of a wave. Unit: Wm-2
