Fig1_5 Black body radiation

Fig1_5 Black body radiation

Fig. 1.5 . The spectral plot of black body radiation intensity as a function of wavelength depends on the temperature of the gas emitting the radiation. The German physicist Max Planck (1858-1947) derived the formula that describes the shape and peak of this spectrum in 1900, proposing that the radiation energy was quantized and providing a foundation for quantum theory. At higher temperatures the wavelength of peak emission shifts to shorter wavelengths, and the thermal radiation intensity becomes greater at all wavelengths. At a temperature of 6,000 degrees on the kelvin scale, or 6,000 K, the thermal radiation peaks in the visible, or V, band of wavelengths. A hot gas with a temperature of 100,000 K emits most of its thermal radiation at ultraviolet, or UV, wavelengths, while the emission peaks in x-rays when the temperature is 1 million to 10 million K.

Copyright 2010, Professor Kenneth R. Lang, Tufts University