If the temperature of a solid surface changes form 27°C to 627°C, then its emissive power changes in the ratio of
A)3
B)6
C)9
D)27
E)81.

Question

Quizplus · Accepted Answer

The emissive power of a solid surface is proportional to the fourth power of its absolute temperature (in Kelvin). This is described by the Stefan-Boltzmann law. To find the ratio of the change in emissive power, we first convert the temperatures from Celsius to Kelvin (by adding 273) and then apply the fourth power to both.Initial temperature = 27°C = 300KFinal temperature = 627°C = 900KThe ratio of the final emissive power to the initial emissive power is (900/300)^4 = 3^4 = 81.

If the Temperature of a Solid Surface Changes Form 27°C