Speed of light dimensions of a capacitor, whereas the value of the vacuum permeability is fixed at exactly through the definition of the ampere. Rosa and Dorsey used this method in 1907 to find a value of . Another way to measure the speed of light is to independently measure the frequency "f" and wavelength "λ" of an electromagnetic wave in vacuum. The value of "c" can then be found by using the relation "c" = "fλ". One option is to measure the resonance frequency of a cavity resonator. If the dimensions of the resonance cavity are also known, these can be used
Max Planck Institute for the Science of Light Max Planck Institute for the Science of Light The Max Planck Institute for the Science of Light (MPL) performs basic research in optical metrology, optical communication, new optical materials, plasmonics and nanophotonics and optical applications in biology and medicine. It is part of the Max Planck Society and was founded on January 1, 2009 in Erlangen near Nuremberg. The Institute is based on the Max Planck Research Group "Optics, Information and Photonics", which was founded in 2004 at the University of Erlangen-Nuremberg, as a precursor. The institute currently comprises five divisions. The institute currently is organized in five divisions, each