# wave number

wave number
the number of waves in one centimeter of light in a given wavelength; the reciprocal of the wavelength.
[1900-05]

* * *

a unit of frequency in atomic, molecular, and nuclear spectroscopy equal to the true frequency divided by the speed of light and thus equal to the number of waves in a unit distance. The frequency, symbolized by the Greek letter nu (ν), of any wave equals the speed of light, c, divided by the wavelength λ: thus ν = c/λ. A typical spectral line in the visible region of the spectrum has a wavelength of 5.8 × 10-5 cm; this wavelength corresponds to a frequency (ν) of 5.17 × 1014 Hz (hertz equals one cycle per second) obtained from the equation. Because this frequency and others like it are so extremely large, it is convenient to divide the number by the speed of light and hence reduce its size. Frequency divided by the speed of light is ν/c, which from the above equation is 1/λ. When wavelength is measured in metres, 1/λ represents the number of waves of the wave train to be found in a length of one metre or, if measured in centimetres, the number in one centimetre. This number is called the wave number of the spectrum line. Wave numbers are usually measured in units of reciprocal metres (1/m, or m-1) and reciprocal centimetres (1/cm, or cm-1).

* * *

Universalium. 2010.

### Look at other dictionaries:

• wave number — bangos skaičius statusas T sritis Standartizacija ir metrologija apibrėžtis Dydis, apibūdinantis elektromagnetinės bangos lauko stiprio kitimo erdvėje dažnį. Jis atvirkščiai proporcingas bangos ilgiui, t. y. σ = 1/λ; čia λ – bangos ilgis.… …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

• wave number — bangos skaičius statusas T sritis chemija apibrėžtis Dydis, atvirkščias bangos ilgiui. atitikmenys: angl. wave number rus. волновое число …   Chemijos terminų aiškinamasis žodynas

• wave number — bangos skaičius statusas T sritis fizika atitikmenys: angl. wave number vok. Wellenzahl, f rus. волновое число, n pranc. nombre d’onde, m …   Fizikos terminų žodynas

• wave number — wave′ num ber n. phs the number of waves in one centimeter of light in a given wavelength; the reciprocal of the wavelength • Etymology: 1900–05 …   From formal English to slang

• wave number — noun the reciprocal of the wavelength of a wave • Hypernyms: ↑frequency, ↑frequence, ↑oftenness • Hyponyms: ↑rydberg, ↑rydberg constant, ↑rydberg unit …   Useful english dictionary

• wave number — noun Date: 1873 the number of waves per unit distance of radiant energy of a given wavelength ; the reciprocal of the wavelength …   New Collegiate Dictionary

• wave number — noun The number of waves per unit length; the reciprocal of wavelength …   Wiktionary

• wave number — (Physics) number of waves in radiant energy of a certain wavelength over a distance of one centimeter (reciprocal of wavelength) …   English contemporary dictionary

• wave number — noun Physics the number of waves in a unit distance …   English new terms dictionary

• wave number — /ˈweɪv nʌmbə/ (say wayv numbuh) noun the number of waves per unit length; the reciprocal of wavelength …