Problem 2 - How Important is BBR? Consider a box lled with an ideal gas with number density n (2 N/V) held at temperature 7'. Assume there's only the ideal gas and black-body radiation in the box. If you use a formula that you don't derive, please indicate the source of the formula (ag. text Eq. N.N, HVV soln Y.Y, etc). (a) (2 points) Calculate the ratio of the total average energy of the ideal gas Ufa to the total average energy of the thermal radiation (photons) U T, in terms of the given variables and any needed constants. (b) (2 points] Now do an explicit calculation of U [G / U.F for air at standard temperature T = 293 K and pressure p = 1.0 x 105 N / mg. Assume that the particles are nitrogen molecules you can ignore any internal motion of the molecules. (you should nd that BBB is not too important here). (c) (2 points) Now do an explicit calculation of U Ia / U1. for the conditions of Silicon burning in a massive star. Silicon burning is the last nuclear fusion process that occurs in such stars. Note that for Si burning T 2 3 X 109 K1 the mass density is p 2 3 X 1010 kg/m3 and the mass of the Si atom is basically the same as a nitrogen molecule