Topic 4

• The maximum displacement of a wave from its undisturbed (equilibrium) position.

  Amplitude
• The angle between the incident ray and the normal.

  Angle of Incidence
• The angel between the reflected ray and normal.

  Angle of Reflection
• A method of producing an image of a foetus in a womb through the emmison, reflecting and detection of ultrasound waves.

  Foetal Scanning
• Sound waves that have a frequency lower than the lower limit of human hearing (20Hz).

  Infrasound
• The angle of incidence must always equal the angle of reflection when a wave reflects.

  Law of Reflection
• The changing of speed, and consequently the direction, of a wave as it changes medium. The wavelength of the wave will also change but the frequency remains constant

  Refraction
• Waves that are produced by earthquakes.

  Seismic Waves
• A method of determining distances in water using the emission, reflection and detection of ultrasound waves.

  Sonar
• The time it takes for one complete wave to pass a given point. It is the inverse of frequency.

  Time Period
• Waves that have a frequency higher than than the upper limit of human hearing (20kHz).

  Ultrasound Waves
• An imaginary surface representing points of a wave that are at the same point in their cycle.

  Wavefront