Waves

• Wavelength


  The distance between equivalent points on two adjacent waves
• Displacement of a wave

  The distance the wave is from its equilibrium position
• Amplitude of a wave

  The wave's maximum displacement from its equilibrium position
• Frequency of a wave

  The number of waves that pass a point each second
• Unit of frequency


  Hertz (Hz)
• Time period of a wave

  The time it takes for a whole wave to pass a given point
• Frequency=


  1/Time Period
• Phase of a wave


  A measure of how far through its cycle a wave is
• In phase


  Two waves are at the same position in their cycles, with a phase difference of zero (or a multiple of 360°)
• Antiphase


  The waves are an odd multiple of 180°/π radians out of phase
• Coherent waves have a constant phase difference
• Path difference


  The difference between the distances travelled by two waves
• Standing wave


  A wave that appears to remain in a fixed position
• Effect that produces a standing wave

  Superposition
• Standing waves store energy - they don't transfer it from one point to another
• Formation of a standing wave

  1. When waves meet in phase, constructive interference occurs and an antinode is formed

  2. When waves meet in antiphase, destructive interference occurs and a node is formed
• Antinode


  A point of maximum displacement
• Node


  A point of zero displacement
• An antinode will always form at the open end of a tube
• A node will always form at the closed end of a tube</b>
• The distance between two adjacent nodes is equal to half the wavelength of the standing wave
• Standing waves can be formed in both transverse and longitudinal waves
• Refraction


  The change in speed of a wave as it changes medium, causing a change in direction
• Wave passing from a less dense medium into a more dense one

  The wave speed will reduce, and it will bend towards the normal
• Wave passing from a less dense medium into a more dense one


  The angle of refraction will be greater than the angle of incidence
• Refractive index


  The ratio of the speed of light in two different mediums
• Absolute refractive index


  The ratio of the speed of light in a material to the speed of light in a vacuum
• Diffraction


  The spreading out of waves as they pass through a gap
• Diffraction is at its greatest when the wavelength and the gap are of the same magnitude
• Young's double slit experiment

  An experiment that supported the wave theory of light
• The light rays passing through each gap in Young's double slit experiment diffracted and interfered with each other to form a series of bright and dark fringes
• Production of bright fringes in Young's double slit experiment

  The two waves meet in phase and so constructively interfere to produce a point of maximum intensity
• Production of dark fringes in Young's double slit experiment

  The two waves meet in antiphase and so destructively interfere to produce a point of minimum intensity
• Phase

  V= FA
• $

  ware 3
• Two coherent Sauces have

  Fixed phase relationship