Stefan Boltzmann Law

Blackbody Radiation Engineering calculations of thermal radiation from surfaces are best keyed to the radiation characteristics of the blackbody, or ideal radiator. The characteristic properties of a blackbody are that it absorbs all the radiation incident on its surface and that the quality and intensity of the radiation it emits are completely determined by its temperature. The total radiative fliix throughout a hemisphere from a black surface of area A and absolute temperature T is given by the Stefan-Boltzmann law ... 

I By Radiation (Wr) This heat loss is related to the difference of the fourth power of the absolute temperatures and the emissivity of the enclosure, and is represented by the Stefan-Boltzmann law expressed by (see Dwight ci al.. 1940)... 

Stefan-Boltzmann law and is usually written The name Stefan-Boltzmann law... 

The most common states of a pure substance are solid, liquid, or gas (vapor), state property See state function. state symbol A symbol (abbreviation) denoting the state of a species. Examples s (solid) I (liquid) g (gas) aq (aqueous solution), statistical entropy The entropy calculated from statistical thermodynamics S = k In W. statistical thermodynamics The interpretation of the laws of thermodynamics in terms of the behavior of large numbers of atoms and molecules, steady-state approximation The assumption that the net rate of formation of reaction intermediates is 0. Stefan-Boltzmann law The total intensity of radiation emitted by a heated black body is proportional to the fourth power of the absolute temperature, stereoisomers Isomers in which atoms have the same partners arranged differently in space, stereoregular polymer A polymer in which each unit or pair of repeating units has the same relative orientation, steric factor (P) An empirical factor that takes into account the steric requirement of a reaction, steric requirement A constraint on an elementary reaction in which the successful collision of two molecules depends on their relative orientation. 

The total quantity of radiation emitted by a black body can be calculated by integrating the curves of Figure 3.19. This has been supplemented by experimental data. The result is the Stefan-Boltzmann law, which is given by... 

The Net OLR, Aq (W m-2), from the ground surface to the atmosphere is given by the Stefan-Boltzmann law. The linear temperature change between the surface temperature of the Earth (Ts) and the effective temperature of the atmosphere (Te) indicates that the radiation occurs layer-by-layer through the atmosphere (Figure 9). Since the net OLR is constant through the atmosphere the net OLR through layer n is... 

Also known as the Stefan-Boltzmann law. The total radiation from a black body is proportional to the fourth power of its absolute temperature. 

The first of the laws is the Stefan-Boltzmann Law relating the amount of energy emitted from a black body, F, to its temperature T ... 

This quantity is the total amount of radiation at all wavelengths radiating through the surface of the sphere and is simply the Stefan-Boltzmann Law multiplied by the surface area of the photosphere. 

The Stefan-Boltzmann Law and Wien s Law for black body radiation have been unified into Planck s Law for black body radiation, from which Planck s constant was first introduced. Planck s analysis of the spectral distribution of black body radiation led him to an understanding of the quantisation of energy and radiation and the role of the photon in the theory of radiation. The precise law relates the intensity of the radiation at all wavelengths with the temperature and has the form ... 

Stefan-Boltzmann Law The relation between temperature and luminosity of a star. 

The measurement of an enthalpy change is based either on the law of conservation of energy or on the Newton and Stefan-Boltzmann laws for the rate of heat transfer. In the latter case, the heat flow between a sample and a heat sink maintained at isothermal conditions is measured. Most of these isoperibol heat flux calorimeters are of the twin type with two sample chambers, each surrounded by a thermopile linking it to a constant temperature metal block or another type of heat reservoir. A reaction is initiated in one sample chamber after obtaining a stable stationary state defining the baseline from the thermopiles. The other sample chamber acts as a reference. As the reaction proceeds, the thermopile measures the temperature difference between the sample chamber and the reference cell. The rate of heat flow between the calorimeter and its surroundings is proportional to the temperature difference between the sample and the heat sink and the total heat effect is proportional to the integrated area under the calorimetric peak. A calibration is thus... 

Steeping parameters, 15 528t Steep tanks, 15 527-528 Stefan-Boltzmann law, 19 131 Stefan-Maxwell equations, 1 43-46, 598 Stefan s law, 7 327 Steinhart-Hart equation, 24 451 Stellite 1... 

The rate of radiant thermal energy transfer between two bodies is described by the Stefan-Boltzmann law. Originally proposed in 1879 by Joseph Stefan and verified in 1884 by Ludwig Boltzmann, the Stefan-Boltzmann law states thatthe emission of thermal radiative energy is proportional to the fourth power of the absolute temperature (Kelvin or Rankine) ... 

The remaining mechanism by which heat is transferred is radiation, that is electromagnetic radiation in the range 0.1—lOOjum. The Stefan— Boltzmann Law for a black body states... 

The total energy E, of all wavelengths radiated per m2 per second by a black body at temperature TK is given by the Stefan-Boltzmann law... 

In 1879, Josef Stefan investigated the increasing brightness of a black body as it is heated and discovered that the total intensity emitted over all wavelengths increases as the fourth power of the temperature (Fig. 1.5). This quantitative result is now called the Stefan-Boltzmann law and is usually written... 

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