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  2. Planck units - Wikipedia

    en.wikipedia.org/wiki/Planck_units

    The Planck temperature T P is 1.416 784 (16) ... Normalizes the characteristic impedance Z g of gravitational radiation in free space to 1 (normally expressed as ...

  3. Planck's law - Wikipedia

    en.wikipedia.org/wiki/Planck's_law

    According to Planck's distribution law, the spectral energy density (energy per unit volume per unit frequency) at given temperature is given by: [4] [5] (,) = ⁡ alternatively, the law can be expressed for the spectral radiance of a body for frequency ν at absolute temperature T given as: [6] [7] [8] (,) = ⁡ where k B is the Boltzmann ...

  4. Brightness temperature - Wikipedia

    en.wikipedia.org/wiki/Brightness_temperature

    For a black body, Planck's law gives: [8] [11] = where (the Intensity or Brightness) is the amount of energy emitted per unit surface area per unit time per unit solid angle and in the frequency range between and +; is the temperature of the black body; is the Planck constant; is frequency; is the speed of light; and is the Boltzmann constant.

  5. Black-body radiation - Wikipedia

    en.wikipedia.org/wiki/Black-body_radiation

    Black-body radiation has a characteristic, continuous frequency spectrum that depends only on the body's temperature, [8] called the Planck spectrum or Planck's law. The spectrum is peaked at a characteristic frequency that shifts to higher frequencies with increasing temperature, and at room temperature most of the emission is in the infrared ...

  6. Planckian locus - Wikipedia

    en.wikipedia.org/wiki/Planckian_locus

    T is the temperature of the black body h is the Planck constant c is the speed of light k is the Boltzmann constant. This will give the Planckian locus in CIE XYZ color space. If these coordinates are X T, Y T, Z T where T is the temperature, then the CIE chromaticity coordinates will be = + +

  7. Schwarzschild's equation for radiative transfer - Wikipedia

    en.wikipedia.org/wiki/Schwarzschild's_equation...

    B λ (T) is the Planck function for temperature T and wavelength λ (units: power/area/solid angle/wavelength - e.g. watts/cm 2 /sr/cm) I λ is the spectral intensity of the radiation entering the increment ds with the same units as B λ (T) This equation and various equivalent expressions are known as Schwarzschild's equation.

  8. Wien approximation - Wikipedia

    en.wikipedia.org/wiki/Wien_approximation

    Wien's original paper did not contain the Planck constant. [1] In this paper, Wien took the wavelength of black-body radiation and combined it with the Maxwell–Boltzmann energy distribution for atoms. The exponential curve was created by the use of Euler's number e raised to the power of

  9. Draper point - Wikipedia

    en.wikipedia.org/wiki/Draper_point

    h is the Planck constant, T is temperature (in kelvins). Substituting the Draper point into this equation produces a frequency of 83 THz, or a wavelength of 3.6 μm, which is well into the infrared and completely invisible to the human eye.