Waves

• Whats a waves amplitude


  The amplitude is the maximum displacement from its equilibrium position
• Whats a waves frequency


  The frequency of a wave is the number of complete waves that pass a point per second
• Whats the period of the wave


  The period of a wave is the length of time taken for one complete wave to pass a given point
• Frequency and period relation


  Frequency = 1 / period
• What is wavelength


  The distance between the same point on two adjacent waves
• Wave speed equation


  Speed = frequency x wavelength
• Whats a longitudinal wave


  Particle oscillations are parallel to the direction of waves motion, containing rarefactions and compressions
• Whats a transverse wave


  Particle oscillations are perpendicular to the direction of the waves motion consisting od peaks and troughs
• Whats a progressive wave


  A progressive wave is one that transfers energy from one point to another without any transfer of matter
• Whats a standing wave


  A wave that stores energy rather than transferring it from one place to another
• What does path difference measure


  Its a measure of how far ahead one wave is compared to another
• What is a waves phase


  A waves phase at a given point is a measure of how far through its cycle the wave is
• Whats the phase difference between two waves at a given point


  The phase difference is the difference between the phases of two waves
• What is interference


  When two waves meet
• What is constructive interference


  When two waves meet in phase
• Whats destructive interference


  When two waves meet in antiphase
• How is a standing wave formed on a string


  • A wave reflects from a closed end meaning two identical waves are travelling in opposite directions down the same string
  • At points where the waves meet in phase, constructive interference occurs and an antinode is formed
  • At points where the waves meet in antiphase destructive interference occurs and a node is formed
• What is a node


  A node is a point of minimum displacement
• What is an antinode


  An antinode is a point of maximum displacement
• What two factors does the speed of a transverse wave on a string depend on


  • Tension
  • Mass per unit length of the string
• Transverse wave on a string equation


  v = (square root) T / U
• What is unpolarised light


  Oscillations in many directions which are perpendicular to the direction of energy transfer
• What is polarised light


  Oscillations in singular directions which are perpendicular to direction of energy transfer
• What is polarisation


  The process of selecting one out of the infinitely many planes of vibration
• What determines the rate at which energy is delivered by a wave

  Intensity/Amplitude of the wave
• Displacement time wave graph characteristics

  • Amplitude
  • Period
  • Frequency
• Convex lenses form


  Virtual and real image
• Concave lenses form


  Real images
• Photon and electron interaction

  A single photon can be absorbed/emitted by a single electron which gains/loses the energy of a photon