Modern Physics

Blackbody radiation The body which absorbs all the radiation falling on it irrespective of frequencies is called a Blackbody. The most important part of a Blackbody are its properties. Blackbody radiates more radiation when it is hot than when it is cold. The spectrum of a Blackbody is given below Spectrum of Blackbody radiation. From the spectrum of Blackbody radiation the following observations are made: 1. With the increase in temperature Blackbody radiates more and more energy. 2. The spectral energy of a Blackbody depends only on temperature . This relation was given by Stefan and Boltzmann known as Stefan's Boltzmann law as                 E 𝛂 T⁴                 E = 𝝈T⁴ 3. The spectral energy density increase with increase in frequency but for higher frequencies it decreases. 4. A relation between temperature and frequency of a Blackbody was given by Wein's law i.e       λₘT=hc=2.898...