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MHT CET 2019 (2 May, Shift 2) · Thermal Radiation: Black Body, Stefan & Wien

Thermal Radiation: Black Body, Stefan & Wien question from MHT CET 2019 (2 May, Shift 2)

Q99MHT CET 2019 · 2 MAY · SHIFT 2Medium

Thermal Radiation: Black Body, Stefan & Wien

The maximum wavelength of radiation emitted by a star is 289.8 nm. Then intensity of radiation for the star is (Given: Stefan's constant =5.67×10−8 W m−2 K−4= 5.67 \times 10^{-8}\text{ W m}^{-2}\text{ K}^{-4}, Wien's constant, b=2898 μm Kb = 2898\,\mu\text{m K})

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Answer: (c)

  1. Wien's law: T=bλm=2898×10−6289.8×10−9=104 KT = \frac{b}{\lambda_m} = \frac{2898 \times 10^{-6}}{289.8 \times 10^{-9}} = 10^4\text{ K}
  2. Intensity =σT4=5.67×10−8×1016= \sigma T^4 = 5.67 \times 10^{-8} \times 10^{16}
  3. =5.67×108 W m−2= 5.67 \times 10^{8}\text{ W m}^{-2}, so the answer is (c).
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