Problem 5.252

There are two cavities (Fig. 5.39) with small holes of equal diameters $d=1.0 \mathrm{~cm}$ and perfectly reflecting outer surfaces. The distance between the holes is $l=10 \mathrm{~cm}$. A constant temperature $T_{1}=1700 \mathrm{~K}$ is maintained in cavity $1 .$ Calculate the steady-state temperature inside cavity 2 .

Instruction. Take into account that a black body radiation obeys the cosine emission law.