cavity radiation การใช้

• In thermodynamic equilibrium the cavity radiation will precisely obey Planck's law.
• Black-body radiation provides insight into the thermodynamic equilibrium state of cavity radiation.
• In 1898, Otto Lummer and Ferdinand Kurlbaum published an account of their cavity radiation source.
• When the small piece of carbon is put in, it transduces amongst radiation frequencies so that the cavity radiation comes to thermodynamic equilibrium.
• Published by Albert Einstein in September 1905 in the " Annalen der Physik "  a few editions after Hasen鰄rl published his results on cavity radiation.
• When there is thermodynamic equilibrium at temperature, the cavity radiation from the walls has that unique universal value, so that " B ? " ( " T " ) } }.
• In this sense, thermodynamic equilibrium cavity radiation may be regarded as thermodynamic equilibrium black-body radiation to which Kirchhoff's law applies exactly, though no perfectly black body in Kirchhoff's sense is present.
• The importance of the Lummer and Kurlbaum cavity radiation source was that it was an experimentally accessible source of black-body radiation, as distinct from radiation from a simply exposed incandescent solid body, which had been the nearest available experimental approximation to black-body radiation over a suitable range of temperatures.
• In the laboratory, black-body radiation is approximated by the radiation from a small hole in a large cavity, a hohlraum, in an entirely opaque body that is only partly reflective, that is maintained at a constant temperature . ( This technique leads to the alternative term " cavity radiation " . ) Any light entering the hole would have to reflect off the walls of the cavity multiple times before it escaped, in which process it is nearly certain to be absorbed.