CP4-waves

• Waves


  Transfer energy from one place to another but do not transfer matter
• Types of waves


  • Transverse
  • Longitudinal
• Transverse wave


  A wave for which the oscillations(vibrations) are at a right angle to the direction of energy transfer
• Longitudinal wave


  A wave for which the oscillations are parallel to the direction of energy transfer
• Transverse waves


  • Electromagnetic waves
  • Seismic s-waves
• Longitudinal waves


  • Sound waves
  • Seismic p-waves
• Parts of a transverse wave


  Peaks and troughs
• Amplitude

  The maximum displacement of a point on a wave from its rest position
• Wavelength


  The distance from a point on a wave to the same position on the adjacent wave, most commonly peak to peak or trough to trough
• Frequency


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


  Hertz, Hz
• Wave speed


  The speed at which energy is transferred through a medium
• Waves transfer energy
• Wave speed

  Wave speed (measured in metres per second) is equal to the product of the wavelength and frequency of the wave
• Calculating wave speed

  1. Wave Speed = Frequency x Wavelength

  2. Speed (m/s), Frequency (Hz), Wavelength (m)
• Period of a wave

  The length of time it takes for one full wave to pass through a point
• Name three different types of waves

  light waves

  sound waves

  seismic waves
• what word is used to describe waves on water?

  transverse waves
• what are waves?


  oscillations that transfer energy from one place to another without transferring any matter
• Do transverse waves move in the same direction that the wave is travelling or different?

  They move at a right angle to the direction that the wave is travelling so they move in a different direction
• If a wave has a large wavelength, then the wave points e.g crests will be further apart
• if a wave has a short wavelength the wave points e.g crests are close together
• what are the two calculations for wave speed?

  Frequency x wavelength

  distance/time
• Wave speed equation


  Wave Speed = Frequency x Wavelength
• Wave speed units


  Speed (m/s), Frequency (Hz), Wavelength (m)
• Reflection


  When a wave bounces off a surface
• Normalline

  A vertical imaginary line which is perpendicular to the boundary
• Refraction


  The change in speed of a wave as it reaches a boundary between two media, usually resulting in a change in direction (if it enters at an angle)
• Refraction of light


  1. Light changes speed and direction in the new medium

  2. If the new medium is more dense, the light will travel slower and bend towards the normal

  3. If the new medium is less dense, the light will travel faster and bend away from the normal
• When entering a denser material


  Light waves slow down and bend towards the normal
• When light waves enter a less dense material, what do they do?

  Light waves speed up and bend away from the normal line
• Measuring refraction


  The angle of incidence, i, and angle of refraction, r, can be measured and compared. All angles are measured relative to the normal.
• Absorption of different wavelengths in different mediums


  • Some materials behave differently depending on the wavelength
  • An example is glass which will transmit visible light, but reflect UV light
• Sound waves in solids

  The particles in the solid vibrate and transfer kinetic energy through the material