Maxwell’s theory of electromagnetic radiation

After holding posts at the universities of Munich and Kiel, Planck succeeded Kirchhoff at the University of Berlin in 1888 after the latter s death. Planck continued his research in thermodynamics, including attempts to connect heat with the Scottish physicist James Clerk Maxwell s theory of electromagnetic radiation. He also addressed a problem suggested by Kirchhoff, who had earlier established that the energy of radiation emitted by a blackbody depends on temperature and the frequency of the radiation. 

It follows from Maxwell s theory of electromagnetic radiation that e = n, where s is the dielectric constant measured at the frequency for which the refractive index is n. Equation (9.8) thus leads immediately to the Lorentz-Lorenz equation... 

Heinrich Rudolf Hertz (1857-1894). German physicist. He performed a number of experiments confirming Maxwell s theory of electromagnetic radiation. His discovery of radio waves led to the development... 

Maxwell s theory of electromagnetic radiation fits within the classical doctrine because the electric and magnetic fields (and their rates of change with time) take on well-defined values at all times and the future values of the fields can be predicted with arbitr y precision fr MJjlSif iililial te usiiig the Maxwell equations. In Maxwell s theoryV] f upon the amplitude of the elec-... 

Theory The initial understanding of the refraction of light dates back to Maxwell s study of electromagnetic radiation. Ernst Abbe invented the first commercial refractometer in 1889 and many refractometers still use essentially the same design. 

The nuclear theory of the atom assumed that the negatively charged electron was in orbit about a more massive nucleus. However, Maxwell s theory of electromagnetism requires that when charged matter changes its direction, it must emit radiation as it accelerates. But electrons in atoms don t emit radiation as they orbit the nucleus, as far as scientists could tell. 

It is universally agreed nowadays that radiation is electromagnetic in character. When an electrically charged particle is subjected to rapid accelerations it produces electromagnetic disturbances in the surrounding space. The nature of these disturbances can.be calculated by Maxwell s theory of the electro-... 

Max Planck in 1900 derived the correct form of the blackbody radiation law by introducing a bold postulate. He proposed that energies involved in absorption and emission of electromagnetic radiation did not belong to a continuum, as implied by Maxwell s theory, but were actually made up of discrete bundles—which he called quanta. Planck s idea is traditionally regarded as the birth of quantum theory. A quantum associated with radiation of frequency v has the energy... 

In view of the experimental difficulties a theory for radiation properties is desirable. The classical theory of electromagnetic waves from J.C. Maxwell (1864), links the emissivity e x with the so-called optical constants of the material, the refractive index n and the extinction coefficient k, that can be combined into a complex refractive index n = n — ik. The optical constants depend on the temperature, the wavelength and electrical properties, in particular the electrical resistivity re of the material. In addition, the theory delivers, in the form of Fresnel s equations, an explicit dependence of the emissivity on the polar angle / , whilst no dependence on the circumferential angle ip appears, as isotropy has been assumed. 

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