# Light wave

Calculates the characteristics of a light wave in air or vacuum.

Use this calculator to convert one of the following light wave characteristics into another : frequency, wavelength, photon energy, temperature, wavenumber, spectroscopic wavenumber and color (for visible light).

## Light wave formulas

We consider a light wave which propagates in a medium of refractive index n = 1 (ie air or vacuum). Its characteristics are denoted as follows,

f: frequency in hertz (Hz)
lambda: wavelength in meter (m)
E: a photon energy in joule (J)
T: Temperature in Kelvin (K)
n: wavenumber in rad/m
ns: spectroscopic wavenumber in 1/m or m-1
c: speed of light in vacuum

### Relationship between frequency and wavelength

f = c/lambda

### Photon energy

E = (h*c)/lambda

h is the Planck constant, h = 6.62607015.10-34 J.s

### Temperature

Temperature is calculated by using Wien law formula which establishes a relationship between the temperature of a body emitting radiation and the wavelength of peak emission lambda_max.

T = (2.8977719 * 10^(-3))/ lambda_max

with T in Kelvin and lambda_max in meter.

### Wavenumber

The wavenumber also called angular wavenumber is calculated as follows,

n=(2*pi)/lambda

### Spectroscopic wavenumber

ns=1/lambda