waves and wave movement

Cards (29)

  • Wave
    A means of transferring energy from one place to another via a travelling disturbance or oscillation
  • Transverse wave
    • Direction of vibration is perpendicular to the direction in which the wave travels
  • Longitudinal wave
    • Direction of vibration is parallel to the direction in which the wave travels
  • examples of longitudinal waves are:
    • Sound waves in solid, liquid or gas
    • Compression waves on a spring
  • Wavelength
    The distance from one point on the wave to the corresponding point on the next cycle
  • Frequency
    A measure of the number of oscillations of the wave per second
  • Periodic time
    The time it takes to complete one full cycle
  • Amplitude
    The maximum displacement from the mean position, measured in metres
  • Characteristics of a wave
    • Reflection
    • Refraction
    • Diffraction
    • Interference
  • Reflection
    The bouncing of waves off an obstacle in their path
  • Refraction
    The changing of direction (by the changing of speed) of a wave as it travels from one medium to another, with frequency remaining constant
  • Diffraction
    The spreading of waves around a slit or an obstacle, significant when slit width is approximately the same size as the wavelength
  • Interference
    The meeting of waves from two sources to produce a wave of different amplitude
  • Coherent waves
    Waves with the same frequency and are in phase (or have a constant phase difference)
  • Constructive interference
    Waves from two coherent sources meeting to produce a wave of greater amplitude
  • Total constructive interference
    Crests of one wave over crests of another
  • Destructive interference
    Waves from two coherent sources meeting to produce a wave of lower amplitude
  • Total destructive interference
    Crests of one wave over troughs of another, when waves are half a wavelength out of phase
  • Polarised waves
    Waves vibrating in one plane only
  • Stationary/standing waves
    Formed when two periodic waves of the same frequency and amplitude travelling in opposite directions meet
  • Fundamental frequency/first harmonic
    The simplest pattern of a stationary wave
  • Nodes
    Locations where the amplitude is minimum
  • Antinodes
    Locations where the amplitude is maximum
  • Doppler effect
    The apparent change in the frequency of a wave due to the relative motion between the source and the observer
  • Applications of Doppler effect
    • Police speed traps
    • Monitoring blood movement or heartbeat of a foetus
    • Weather forecasting
  • to find frequency when given time
    f= 1/T
  • relationship between periodic time and frequency
    T= 1/F
  • distance between 2 consecutive nodes or anti nodes
    lamda/2
  • distance between node and anti-node
    lamda/4