Question

A spherical black body of radiusrat absolute temperature T is surrounded by a thin spherical and concentric shell of radius R, black on both sides. The factor by which this radiation shield reduces the rate of cooling of the body (consider space between spheres evacuated, with no thermal conduction losses) is given by the following expression: аR/(R2 + br”). a and b are numerical coefficient. The ratio is :- (A) 1 (B) 2 (C) 3 (D) 4​

Answer 1

Answer:

Correct answer is (B) 2

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