# Calculations

## Wavelength-energy converter

Here, the characteristic quantities of electromagnetic waves can be calculated.

Wavelength | 1 | nm | Nanometre |

Wavelength | 1⋅10^{-9} | m | Metre |

Frequency | 299.792⋅10^{15} | Hz | Hertz (299.792 PHz) |

Energy | 1.24⋅10^{3} | eV | Electron volt (1.24 keV) |

Energy | 198.623⋅10^{-18} | J | Joule |

Wave number | 10⋅10^{6} | 1/cm | Inverse centimetre |

Range: | XUV |

One of the most important findings while developing the concept of quantummechanics was that light can not only be described as electromagnetic wave but also as particle. This particle is called phonon and it has no rest mass. Between the photon energy and the frequency of the electromagnetic wave there is the following relation:

E = h ⋅ ν

Here h = 4.13566733⋅10^{-15} is the Planck constant.

Since the speed of light c = 299792458 m / s is known, the wavelength can be calculated from the frequency:

λ = c / ν