Final answer:
The question is asking about a spherical black body of radius r that radiates power P and its rate of cooling, which is represented by R. According to Stefan's law, the power radiated by a black body is proportional to the fourth power of its temperature. To compute the total power, we assume that the energy radiates through a spherical surface enclosing the black body.
Step-by-step explanation:
The subject of this question is Physics. The question is asking about a spherical black body of radius r that radiates power P and its rate of cooling, which is represented by R.
According to Stefan's law, the power radiated by a black body is proportional to the fourth power of its temperature. The power radiated per unit area can be calculated using the formula P/A = o*T^4, where o is the Stefan-Boltzmann constant, A is the surface area of the object, and T is its temperature in kelvins.
To compute the total power, we assume that the energy radiates through a spherical surface enclosing the star, so the surface area is A = 4R^2, where R is the radius of the black body.