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GATE 2020 ME (ME2) – Question 60

Heat Transfer · Radiative heat transfer: laws, view factors, radiation network · 2 marks · Numerical answer

A blackbody at T₁ = 3000 K has peak spectral wavelength λₘₐₓ. It cools to T₂, where peak wavelength is 1.2λₘₐₓ. Find T₂ (K), nearest integer.

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Correct answer: 2499 to 2501

Explanation

Wien’s displacement law givesλmaxT=constant. ThereforeT2=T1/1.2=3000/1.2=**2500 K**. Increasing peak wavelength corresponds to decreasing temperature.