bølgetall

Bølgetall, often denoted by the Greek letter sigma (σ) or kappa (κ), is a concept used in physics and chemistry to describe the spatial frequency of a wave. It is defined as the number of wavelengths that fit into a unit of distance, typically one meter. Mathematically, bølgetall is the reciprocal of the wavelength (λ). Therefore, σ = 1/λ.

This quantity is particularly useful in spectroscopy and the study of wave phenomena. For instance, in atomic spectroscopy, the energy levels of atoms can be related to the bølgetall of the emitted or absorbed photons. A higher bølgetall corresponds to a shorter wavelength and thus higher energy, while a lower bølgetall signifies a longer wavelength and lower energy.

The units of bølgetall are inverse length, commonly expressed as per meter (m⁻¹) or per centimeter (cm⁻¹). The latter is often referred to as wavenumber. When discussing electromagnetic radiation, the bølgetall is directly proportional to frequency and energy, offering an alternative way to characterize spectral lines or wave properties. Its use simplifies certain equations in wave mechanics and quantum mechanics, making it a convenient parameter for calculations and analysis.