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PHYSICS

A wave has a certain speed, frequency, and wavelength. These are connected by a simple relation: Speed = Frequency * Wavelength The wavelength (sometimes referred to as lambda, λ) is the distance measured from a point on one wave to the equivalent part of the next (or, in a more technical way, to the next point that is in the same phase), for example from the top of one peak to the next. The frequency is the number of whole waves that pass a fixed point in a period of time. Speed is measured in metres/second, frequency is measured in cycles per second (or Hertz, represented by the symbol Hz), and wavelength is measured in metres. For example, if a wave on water travels at one metre per second, and it oscillates five times per second, then each wave will be twenty centimetres long: 1 metre/second = 5 cycles/second *W W = 1 / 5 metres W = 0.2 metres = 20 cm Waves also have a property called amplitude. This is the distance from the centre of the wave to the extreme of one of its peaks, and can be thought of as the “height” of a water wave. Frequency, wavelength, and amplitude are shown in Figure RP 1.

Figure RP 1: Wavelength, amplitude, and frequency. For this wave, the frequency is 2 cycles per second, or 2 Hz, while the speed is 1 m/s.