Two stars,A and B,have the same emissivity,but the radii and surface temperatures are different with R_A = 2 R_B,and T_A = 0.5 T_B.Assuming the temperature of space to be negligible,which star radiates the most energy per unit time? A) Star A B) Star B C) Both radiate the same amount of energy per unit time. D) More information is needed in order to make a determination.

Question

Quizplus · Accepted Answer

The rate at which energy radiated from a star is given by the Stefan-Boltzmann law, which states that the energy radiated per unit time per unit surface area is proportional to the fourth power of the surface temperature. Since both stars have the same emissivity, the one with the larger surface area (star B) will radiate more energy per unit time. Additionally, since the surface temperature of star B is higher than that of star A, the energy radiated per unit area will be even greater. Therefore, star B radiates more energy per unit time.

Two Stars,A and B,have the Same Emissivity,but the Radii and Surface