State (i) Stefan-Boltmann law and (ii) Wein’s displacement law. - Vidyadip

Question

State (i) Stefan-Boltmann law and
(ii) Wein’s displacement law.

✓

Answer

(i) The Stefan-Boltzmann law : The rate of emission of radiant energy per unit area or the power radiated per unit area of a perfect blackbody is directly proportional to the fourth power of its absolute temperature. OR
The quantity of radiant energy emitted by a perfect blackbody per unit time per unit surface area of the body is directly proportional to the fourth power of its absolute temperature.
(ii) Wien’s displacement law : The wavelength for which the emissive power of a blackbody is maximum, is inversely proportional to the absolute temperature of the blackbody.
OR
For a blackbody at an absolute temperature T, the product of T and the wavelength $\lambda _m$ corresponding to the maximum radiation of energy is a constant.
$λ_mT$ = b, a constant.
[Notes: (1) The law stated above was stated by Wilhelm Wien (1864-1928) German Physicist. (2) The value of the constant b in Wien’s displacement law is $2.898 \times 10^{-3} m.K.$]

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