Radiation defined

The acronym LASER (Light Amplification via tire Stimulated Emission of Radiation) defines the process of amplification. For all intents and purjDoses tliis metliod was elegantly outlined by Einstein in 1917 [H] wherein he derived a treatment of the dynamic equilibrium of a material in a electromagnetic field absorbing and emitting photons. Key here is tire insight tliat, in addition to absorjDtion and spontaneous emission processes, in an excited system one can stimulate tire emission of a photon by interaction witli tire electromagnetic field. It is tliis stimulated emission process which lays tire conceptual foundation of tire laser. 

Reflectance A measure of the extent to which a surface is capable of reflecting radiation, defined as the ratio of the intensity of reflected radiant flux to the intensity of the incident flux. 

Not to be confused with insulation, the word insolation (acronym for incoming solar radiation") defines the rate at which direct solar radiation is incident upon a unit horizontal surface at any point on or above the surface of the earth. The unit of insolation is the Langley, named after Samuel Pierpoint Langley (1834-1906). an American astronomer, physicist and pioneer in the utilization of solar energy ... 

Oscillator strength or transition probability is the individual characteristic of a separate atom or ion. However, in reality we usually have to deal with a large number of them, where, depending on the specific physical situation, various elementary processes of excitation, ionization, recombination, etc. may take place. Real spectral lines are characterized by the intensity of radiation, defined in the conditions of natural isotropic excitation as... 

Raman spectrum. In order to make Raman spectra easier to evaluate, frequency shifts are usually recorded the exciting radiation defining the zero frequency shift. 

C How i.s the intensity of emitted radiation defined For a diffusely emitting surface, how is the emissive power related to (he intensity of emitted radiation ... 

It should be mentioned here that the quantum multipole radiation, defined in terms of the source, has also been considered [56]. 

The advent of a radiation defined to 1 part in 10 to 10 prompted many physicists to find means of using it to verify some of the predictions of relativistic mechanics experimentally. In fact, many of the early Mossbauer experiments were directed towards such ends. After an early flood of papers, it was realised that many of the experiments could not provide an unambiguous proof of the validity of the physical laws with which they were predicted and interpreted, and consequently interest waned again. However, many of the experiments are extremely interesting in their own right, and some of them will now be outlined. 

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