Answer:
Star A is this many times (9000)^4 x [4 π R^2 σ] brighter than Star B = (3000)^4 x [4 π R^2 σ]
Explanation:
In accordance with the Stefan-Boltzmann Law,
L = 4 π R^2 σ Τ^4
(Where L = is the energy emitted out by star i.e., Brightness, R = Radius of the star, σ = 5.67 x 10^-8 Stefan-Boltzmann Constant and T is the temperature of the star)
Star A = (9000)^4 x [4 π R^2 σ]
Star B = (3000)^4 x [4 π R^2 σ]
