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  2. Emissivity - Wikipedia

    en.wikipedia.org/wiki/Emissivity

    Black soot absorbs thermal radiation very well; it has an emissivity as large as 0.97, and hence soot is a fair approximation to an ideal black body. [21] [22] With the exception of bare, polished metals, the appearance of a surface to the eye is not a good guide to emissivities near room temperature.

  3. Thermal emittance - Wikipedia

    en.wikipedia.org/wiki/Thermal_emittance

    Thermal emittance or thermal emissivity is the ratio of the radiant emittance of heat of a specific object or surface to that of a standard black body.Emissivity and emittivity are both dimensionless quantities given in the range of 0 to 1, representing the comparative/relative emittance with respect to a blackbody operating in similar conditions, but emissivity refers to a material property ...

  4. Kirchhoff's law of thermal radiation - Wikipedia

    en.wikipedia.org/wiki/Kirchhoff's_law_of_thermal...

    Kirchhoff's law of thermal radiation has a refinement in that not only is thermal emissivity equal to absorptivity, it is equal in detail. Consider a leaf. It is a poor absorber of green light (around 470 nm), which is why it looks green. By the principle of detailed balance, it is also a poor emitter of green light.

  5. Thermal radiation - Wikipedia

    en.wikipedia.org/wiki/Thermal_radiation

    Thermal radiation is the emission of electromagnetic waves from all matter that has a temperature greater than absolute zero. [5] [2] Thermal radiation reflects the conversion of thermal energy into electromagnetic energy. Thermal energy is the kinetic energy of random movements of atoms and molecules in matter. It is present in all matter of ...

  6. Stefan–Boltzmann law - Wikipedia

    en.wikipedia.org/wiki/Stefan–Boltzmann_law

    Emissivity can in general depend on wavelength, direction, and polarization. However, the emissivity which appears in the non-directional form of the Stefan–Boltzmann law is the hemispherical total emissivity, which reflects emissions as totaled over all wavelengths, directions, and polarizations. [3]: 60

  7. Planck's law - Wikipedia

    en.wikipedia.org/wiki/Planck's_law

    Further, one may define the emissivity ε ν,X (T X) of the material of the body X just so that at thermodynamic equilibrium at temperature T X = T, one has I ν,X (T X) = I ν,X (T) = ε ν,X (T) B ν (T). When thermal equilibrium prevails at temperature T = T X = T Y, the rate of accumulation of energy vanishes so that q(ν,T X,T Y) = 0.

  8. Thermal expansivities of the elements - Wikipedia

    en.wikipedia.org/wiki/Thermal_expansivities_of...

    As quoted from this source in an online version of: J.A. Dean (ed), Lange's Handbook of Chemistry (15th Edition), McGraw-Hill, 1999; Section 4; Table 4.1, Electronic Configuration and Properties of the Elements Touloukian, Y. S., Thermophysical Properties of Matter, Vol. 12, Thermal Expansion, Plenum, New York, 1975.

  9. Heat capacities of the elements (data page) - Wikipedia

    en.wikipedia.org/wiki/Heat_capacities_of_the...

    J.A. Dean (ed), Lange's Handbook of Chemistry (15th Edition), McGraw-Hill, 1999; Section 6, Thermodynamic Properties; Table 6.3, Enthalpies and Gibbs Energies of Formation, Entropies, and Heat Capacities of the Elements and Inorganic Compounds