Wave motion

• Describing Wave Motion

  • When describing wave motion, there are several terms which are important to know, including:
  • Amplitude
  • Wavelength
  • Frequency
  • Period
• Amplitude

  • Amplitude is defined as: The distance from the undisturbed position to the peak or trough of a wave
  • It is given the symbol A and is measured in metres (m)
  • Amplitude is the maximum or minimum displacement from the undisturbed position
• Wavelength

  • Wavelength is defined as: The distance from one point on the wave to the same point on the next wave.
  • In a transverse wave:
  • The wavelength can be measured from one peak to the next peak
  • In a longitudinal wave
  • The wavelength can be measured from the centre of one compression to the centre of the next
  • The wavelength is given the symbol λ (lambda) and is measured in metres (m)
  • The distance along a wave is typically put on the x-axis of a wave diagram
• Waves:

  A) Wave length

  B) Amplitude

  
• Frequency

  • Frequency is defined as:The number of waves passing a point in a second
  • Frequency is given the symbol f and is measured in Hertz (Hz)
• Time Period

  • The time period of a wave is defined as: The time taken for a single wave to pass a point 
  • This can also be stated as The time taken for one full cycle of a wave
  • The time period is given the symbol T and is measured in seconds (s)
• Frequency equation:

  A) Frequency

  B) Time

  
• The Wave Equation

  • Wave speed is defined as: The distance travelled by a wave each second
  • Wave speed is given the symbol ν and is measured in metres per second (m/s)
  • Wave speed is the speed at which energy is transferred through a medium
• • Transverse and longitudinal waves both obey the wave equation:

  A) Frequency

  B) Wave length

  
• • v = wave speed in metres per second (m/s)
  • f = frequency in Hertz (Hz)
  • λ = wavelength in metres (m)