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UPSC Civil Service Exam Questions - Engineering

Q1:

If the mean temperature of Sun's surface 6000 K and λm of its radiation is 0.5 what is the mean temperature of earth surface for which λm is 10.0 μm, according to Wien's Displacement Law in Remote Seniror Concept ?

A 25 °C

B 28 °C

C 27 °C

D 30 °C

ANS:C - 27 °C

Peak wavelength * temperature = constant.

Temperature at earth = .5 * 6000/10 kelvin = 300 k =27° celcius.