Assuming the sun to have a spherical outer surface of radius r, radiating like a black body at temperature t°C, the power received by a unit surface, (normal to the incident rays) at a distance R from the centre of the sun is (where σ is the Stefan's constant)

Question

Dr. Abubacker · Accepted Answer

[Solution from source] The sun radiates P = 4πr²σ(t + 273)⁴. At distance R this spreads over 4πR², giving r²σ(t + 273)⁴/R² per unit area. Options using t⁴ forget to convert to kelvin, and dividing by an extra 4π is wrong. Answer (3).

Q. Assuming the sun to have a spherical outer surface of radius r, radiating like a black body at temperature t°C, the power received by a unit surface, (normal to the incident rays) at a distance R from the centre of the sun is (where σ is the Stefan's constant)

Explanation

Reviewed by Dr. Abubacker

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