A piece of iron is heated from 400 K to 800 K. The total energy emitted per second by this iron will increase by a factor of
A) 296.5.
B) 4.
C) 2.
D) 16.

Question

Quizplus · Accepted Answer

The total energy emitted per second by a body according to the Stefan-Boltzmann law is proportional to the fourth power of its absolute temperature (E ∝ T^4). Therefore, when the temperature is doubled (from 400 K to 800 K), the energy emitted increases by a factor of (800/400)^4 = 2^4 = 16.

A Piece of Iron Is Heated from 400 K to 800