Waves Definitions

Here are some definitions to learn for the waves topic. Remember you must be able to spell:


Term Definition
Amplitude (A) the distance from the middle of the wave to the top (or the bottom) measured in metres. Maximum displacement from the mean position!
amplitude, (A) maximum disturbance of the particles in a wave. (or distance from middle to top of wave) (m)
Angle of incidence  the angle between an incident ray and the normal (a line perpendicular to the reflecting surface at the point of incidence) (°)
Angle of reflection  the angle between a reflected ray and the normal (°)
Angle of refraction the angle between the light ray in the more optically dense material and the normal. (°)
Critical angle The critical angle is the angle of incidence above which total internal reflection occurs. (°)
Diffraction occurs when wave meet a barrier, the waves bend around an obstacle. Long waves diffract more thank short waves.
Energy and waves Waves transmit energy. The greater the amplitude the more energy is transferred.
Frequency, (f) the number of waves per second. Frequency is measured in hertz (Hz).
Frequency, (f)  number of waves produced or passing a point per second. (Hertz or Hz)
Law of reflection The angle of incidence = the angle of reflection
Longitudinal wave In a longitudinal wave the particles move along the line of the direction of travel of energy.
Normal a line at 90° to the surface at the point of incidence, (from which all angles are measured.)
Period. (T)  Time for one wave to pass a point or time for one wave to be produced. (s)
Principle of reversibility of light The principle of reversibility of light states that a ray of light which travels along any particular path from some point A to another point B travels by the same path when going from B to A.
Reflection when a wave “bounces off” a surface we say it is reflected. (Particles can also reflect)
Refraction when light waves travel from one material to another the waves slow down and there is a reduction in wavelength in the optical thicker material. Unless the waves enter along the normal there is also a change of direction.
Speed, (v) rate of covering a distance. Number of metres travelled per second. (ms-1) The speed of the waves is represented by the formula
Total Internal Reflection When a wave hits a boundary at an angle larger than the critial angle the wave is entirely reflected if the material on the other side of the boundary is less optically dense.
Transverse wave In a transverse wave the particles move at 90 degrees to the direction of the flow of energy.
Wave  a way of transferring energy.
Wave speed the speed at which the wave travels
Wavelength the distance between the same point on successive waves.
Wavelength, (λ)  the distance between two successive points on a wave. (metre or m)
Wavelength, (λ) The wavelength of a wave is the horizontal distance between two adjacent troughs or crests or any two corresponding points on the wave

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