Wave amplitude formula_4 described by the equation: where The units of the amplitude depend on the type of wave. Transverse mechanical waves (e.g., a wave on a string) have an amplitude expressed as a distance (e.g., meters), longitudinal mechanical waves (e.g., sound waves) use units of pressure (e.g., pascals), and electromagnetic waves (a form of transverse vacuum wave) express the amplitude in terms of its electric field (e.g., volts/meter). The wavelength formula_30 is the distance between two sequential crests or troughs (or other equivalent points), generally is measured in meters. A wavenumber formula_17, the spatial frequency of the wave in radians
Sound space. Note that the particles of the medium do not travel with the sound wave. This is intuitively obvious for a solid, and the same is true for liquids and gases (that is, the vibrations of particles in the gas or liquid transport the vibrations, while the "average" position of the particles over time does not change). During propagation, waves can be reflected, refracted, or attenuated by the medium. The behavior of sound propagation is generally affected by three things: When sound is moving through a medium that does not have constant physical properties, it may be refracted (either dispersed