Introduction.
In one phenomena, which are bound to distribution of light, its undular properties (interference, diffraction) are shown. In other phenomena its quantum properties (photoeffect, radiation and uptake of a light, process of interaction of a light with substance) are shown.
The light has simultaneously undular and quantum properties, which are differently shown in the different phenomena. However, when the wave length of a light is diminished, its undular properties are attenuated and the quantum properties are shown.
topñ
Compton's effect.
The experience of Arthur Holly Compton (1892-1962) on a dispersion of Roentgen rays by substances, which consist of atoms of light devices, have shown, that the dispelled Roentgen rays have a major wave length l¢, than impinging l. Thus the residual Dl = l¢ - l depends on properties of scattering substance and wave length of an impinging light:
The quantity lK is a stationary value for all substances also is termed as Compton's wave length, lK = 2,43 x 1012 m. This phenomenon, which is termed as Compton's recoil, is impossible to explain by a wave theory of light. In quantum theory the magnification of wave length of radiation at a dispersion is explained by interaction of photons of impinging radiation with electrons of atoms and molecules. The part of energy of an impinging photon, which is transmitted to electrons of scattering substance, depends on a scattering angle of photon. At q = p, that is provided that after a dispersion a photon will fly in the party, which is opposite to a tentative direction, the losses by a photon of energy will be maximal, that will give in maximal magnification of a wave length of radiation.
topñ
Light pressure.
Some properties, for example light pressure, can be surveyed simultaneously in the electromagnetic theory and in the quantum theory. According to the electromagnetic theory of light, the pressure p, which renders a luminous flux with power W, impinging normally on a simple surface, is equal:
| For an ideal black body (R = 0): p = |
|
| For an absolute reflecting body (R = 1): p = |
|
If N of quantums of a luminous flux with frequency n, which bears(carries) energy W = N · hn, impinges on a simple surface for 1 second, then the blanket impulse at a reflectivity R will look like:
Thus, electromagnetic theory and quantum theory give identical results. However it is essential different representations will be utillized in the electromagnetic and quantum theories of light. The concept of an electromagnetic wave of application to a light guesses existence of a wave in particular field(area) of space, which is capable to contain even some lengths of waves of light. The light quantums are considered as a particle, which are localized in very small volume of space. The representation about a light wave guesses a continuous distribution of energy in a spatial wave, the representation about quantums guesses localization of energy in a small part of space. Both these incompatible representations reflect unity of a wave-corpuscle nature of light, which is shown at distribution of light and its interaction with substance.
topñ
ïback nextð
|
Properties
of a light
introduction
Properties
Examination
of properties
Library
