Quantum hypothesis

The quantum hypothesis states that radiation (e.g. light) cannot exchange any amount of energy with matter , but only certain discrete "energy packages" called quanta (from the Latin quantum = "how much"). The hypothesis was supported by the Max Planck introduced in 1900 in order to be radiation law of black body derive. Accordingly, the amount of energy that is emitted or absorbed by a radiation field of the frequency is always an integral multiple of ${\displaystyle \Delta E}$ ${\displaystyle \nu }$

${\displaystyle \Delta E=h\nu }$,

where is the constant Planck constant . ${\displaystyle h}$

Planck was initially very skeptical of his own hypothesis.

Albert Einstein suggested that these quanta are not just a matter of calculation, but that the radiation field itself consists of quanta. With this hypothesis he succeeded in explaining the experimental findings of the external photoelectric effect . For this work Einstein received the Nobel Prize in 1921 . The term photons was later introduced for light quanta .

The quantum hypothesis turned out to be necessary not only for the derivation of Planck's law of radiation and the photoelectric effect, but also for the explanation of the line spectra and the short-wave limit of X-rays , to name just a few examples.

The work of Planck and Einstein is considered to be the hour of birth of quantum physics . Today quanta are no longer a hypothesis, but an empirical fact. With the photomultiplier, a device is now available with which individual light quanta can be detected and counted.

See also

• Quantization (physics)

Individual evidence

1. ↑ Max Planck: On the theory of the law of energy distribution in the normal spectrum. In: Negotiations of the German physical society. 2, No. 17, 1900, p. 245, Berlin (presented on December 14, 1900; PDF ( Memento of the original of February 4, 2017 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original - and archive link according to the instructions and then remove this note. ). 
2. ↑ "I can only characterize the whole procedure as an act of despair, since I am naturally peaceful and reject all dubious adventures." (Max Planck, quoted from: Tipler, Llewellyn: "Moderne Physik", Oldenbourg 2003, ISBN 3 -486-25564-9 ).
3. ↑ Albert Einstein: On a heuristic point of view relating to the generation and transformation of light , Annalen der Physik 17, 1905, pp. 132ff.