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CHAPTER- STRUCTURE OF ATOM
Relation between intensity ad wavelength

Black Body Radiation: 

 This phenomenon is explained by Max Plank in 1900. When solid is heated it emit radiation over wide range of wavelength .For example when a iron rod is heated it become dull red and then more and more red ,further with increase in temperature it become orange ,yellow ,white and blue at last. The red colour is of higher wavelength and lower frequency and blue colour is of lower wavelength and higher frequency, this means with increase in temperature, wavelength decrease and increase in frequency. An ideal body which emits and absorbs radiation of all wavelengths is called a black body and the radiation emitted by such a body is called black body radiation. Intensity verses wavelength curve depend upon temperature .At a given temperature intensity of radiation emitted increase with decrease of wavelength, it reaches maximum value and then decrease with decrease of wavelength . These results could not be explained by the classical wave theory of light .According to this theory energy is emitted or absorbed continuously .Therefore energy of electromagnetic radiation  is directly proportional to intensity and independent of its frequency and wavelength.




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