Plot a graph for the monochromatic emittance versus wavelength for the radiation emitted by black body. Discuss the interpretations made from graph.
Interpretations from this graph is as follows:
(i) At a given temperature, the energy distribution is not uniform in spectral radiations of a hot black body.
(ii) At a given temperature, emissive power increases first with increases in wavelength. Emissive power is maximum, at a particular wavelength and then it decreases with further increase in wavelength.
(iii) At every temperature, there exists one wavelength at which emissive power of the black body is maximum. This wavelength is called wavelength of maximum emission.
(iv) With increase in temperature, the emissive power corresponding to each wavelength increases.
(v) The wavelength of maximum emission decreases with the increase in temperature.
(vi) The area under each curve represents the total energy emitted by black body per second per unit area.
It is found that the area under the curve varies directly with fourth power of absolute temperature of black body.
i.e. E ∝ T4.
