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Thermal Properties Of Matter

Question
CBSEENPH11026226

A black body has a wavelength of A at temperature 2000 K. Its corresponding wavelength at temperature 3000 K will be

  • 2λ3

  • 3λ2

  • 4λ9

  • 9λ4

Solution

A.

2λ3

Below figure gives the experimental curves for radiation energy per unit area per unit wavelength emitted by blackbody versus wavelength for different temperatures.

    

The wavelength λm for which energy is maximum decreases with increasing temperature. The relation between λm and T is given by Wein's Displacement Law

According to Wein's displacement law,

             λm T = Constant

 ⇒           λ2λ1 = 20003000

                λ2λ = 23

                 λ2 = 23 λ