Waves

• Displacement


  How far a particle is from equilibrium position. A particle can be above(crest) or below(trough) the equilibrium position
• Amplitude (A)


  The maxiumum displacement. Measured in metres
• Wavelength ,\


  The distance between two adjacent crests or troughs. Measured in meters
• Frequency (f)


  The number of waves which pass a point in one second. Measured in Hertz(Hz)
• Time period (T)


  The time it takes for one complete wave to pass.Time between one crest/ trough and the next.Measured in metres
• Longitudinal waves


  Motion of particles is parallel to the direction of the energy transfer
• Transverse waves


  The motion of particles is perpendicular to the direction of energy transfer
• Equation for frequency


  f=1/T

  Frequency= one/ time period
• Equation for speed


  v=λf

  (Speed = wavelength x frequency)
• What do waves do

  Waves transfer energy without transferring matter
• What is the Doppler effect?

  The perceived change in frequency when the source of the waves is moving
• How does the Doppler effect happen?

  Wavefronts are squashed ahead of the source so as the wavelength decreases, frequency increases.

  
  

  Wavefronts are spread out behind the source so as wavelength increases, frequency decreases( constant speed)
• Electromagnetic spectrum order

  radio, microwave, infrared, visible, ultraviolet, x-ray, gamma ray
• Electromagnetic spectrum

  All waves in this spectrum travel at the same speed

  All are transverse

  All can travel through a vacuum