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Explain the influence of Planck's quantum theory on Bohr's model of structure of atom. |
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Answer» Solution :Planck's Quantum Theory : (1) The emission of radiation is due to vibrations of charged particles (ELECTRONS )in the BODY. (2)The emission of a radiation is not continuous , but in discrete packets of energy called 'quanta' . This emitted radiation propagates in the form of waves . (3)The energy ASSOCIATED with each quantum (E) is given by `E=hupsilon` , where `upsilon` is the frequency of radiation and h is Planck's constant `(h=6.63xx10^(-27)"ergs")` (4) A body can emit or absorb either one quantum`(hupsilon)` of energy or some whole number multiples of it . Success of Planck's Quantum Theory : This theory successfully explains the black body RADIATIONS . A black body is a perfect absorber and also a perfect raditor of radiations . Explanation of Graph : The radiations emitted by a hot black body , when passed through a prism , produce a spectrum of different wavelengths . A plot of the 'intensity ' of radiation ' against 'wavelength ' gives a curve. Such curves obtained at different temperatures of a black body are shown in the graph . The following conclusions can be drawn from a study of the shapes of the curves .  (i) At a given temperature , the intensity of radiation increases with wavelength, reaches a maximum and then decreases . (ii) As the temperature increases , the peak of the curve (maximum point in curve )shifts to lower wavelengths . The WAVE theory of light ' could not explain the above experimental results , satisfactorily . |
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