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
Acid dissociation constant proton. The constant for dissociation of the first proton may be denoted as "K" and the constants for dissociation of successive protons as "K", etc. Phosphoric acid, HPO, is an example of a polyprotic acid as it can lose three protons. When the difference between successive p"K" values is about four or more, as in this example, each species may be considered as an acid in its own right; In fact salts of may be crystallised from solution by adjustment of pH to about 5.5 and salts of may be crystallised from solution by adjustment of pH to about 10.