Per unit area (such as a square centimeter), a B star whose surface temperature is 10,000 Kwill put out how much radiation compared to an O star whose surface temperature is 30,000 K?
A)81 times as much
B)9 times as much
C) $1 / 81$ 1 s much
D) $1 / 9$ s much
E) $1 / 3$ 3 s much

Question

Quizplus · Accepted Answer

The radiation output per unit area from a star's surface is given by the Stefan-Boltzmann law, which states that the energy radiated per unit surface area is directly proportional to the fourth power of the black body's temperature in kelvins. Therefore, if the temperature of the O star is 3 times that of the B star (30,000 K / 10,000 K = 3), the radiation output would be $3^4 = 81$ times greater for the O star compared to the B star. Thus, the B star puts out $1 / 81$ as much radiation as the O star.

Per Unit Area (Such as a Square Centimeter), a B 1/811 / 811/81

Per Unit Area (Such as a Square Centimeter), a B $1 / 81$