A black body calorimeter filled with hot water cools from 60°C to 50°C in 4 min and 40°C to 30°C in 8 min. The approximate temperature of surrounding is :
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A black body calorimeter filled with hot water cools from 60°C to 50°C in 4 min and 40°C to 30°C in 8 min. The approximate temperature of surrounding is :

G1 Physics · Accepted Answer

Use Stefan-Boltzmann law P=eσA(T⁴−Tₛ⁴), Wien's law λₘT=b, or Newton's law of cooling dθ/dt=−k(θ−θₛ), as applicable. Evaluating the given data/statements gives B: 15°C. Therefore the correct answer is B.