Per unit area (such as a square centimeter),a B star whose surface temperature is 10,000 K will put out how much radiation compared to an O star whose surface temperature is 30,000 K?

Question

Quizplus · Accepted Answer

The energy output of a star is related to its surface temperature by the Stefan-Boltzmann Law:

L ∝ T^4

where L is the luminosity (energy output), and T is the surface temperature.

Comparing a B star with T = 10,000 K to an O star with T = 30,000 K:

L_B / L_O = (T_B / T_O)^4 
L_B / L_O = (10,000 / 30,000)^4 
L_B / L_O = 1/81

Therefore, the B star puts out 1/81 as much radiation per unit area as the O star.

Per Unit Area (Such as a Square Centimeter),a B Star