An object having a fixed emissivity of 0.725 radiates heat at a rate of 10 W when it is at an absolute temperature T. If its temperature is doubled to 2T, at what rate will it now radiate?
A) 80 W
B) 160 W
C) 320 W
D) 40 W
E) 20 W

Question

Quizplus · Accepted Answer

The rate at which an object radiates heat is given by the Stefan-Boltzmann law, which states that the power radiated per unit area of a black body is proportional to the fourth power of the absolute temperature (P ∝ T^4). When the temperature is doubled (T becomes 2T), the power radiated increases by a factor of (2^4) = 16. Therefore, if the object originally radiates at 10 W, when the temperature is doubled, it will radiate at 10 W * 16 = 160 W.

An Object Having a Fixed Emissivity of 0