An astronomer observes two ordinary stars. The first one turns out to be twice as hot as the second. This means that the first one radiates:
A) twice as much energy as the second
B) roughly the same amount of energy as the second
C) half as much energy as the second
D) about 16 times the energy of the second
E) this problem cannot be solved with just the information we were given

Question

Quizplus · Accepted Answer

The luminosity (energy radiated per second) of a star is related to its temperature by the Stefan-Boltzmann law, which states that the energy radiated per unit area is proportional to the fourth power of the temperature. Therefore, if the first star is twice as hot as the second, it radiates $2^4 = 16$ times as much energy.

An Astronomer Observes Two Ordinary Stars