Solve the following problem:
Q: A solar collector consists of a long duct through which air is blown; its cross section forms an equilateral triangle 1 m on a side. One side consists of a glass cover of emissivity e1 = 0.9, while the other two sides are absorber plates with e2 = e3 = 1.0. During operation the surface temperatures are known to be T1 = 25°C, T2 = 60°C, and T3 = 70°C. What is the net rate at which radiation is transferred to the cover due to exchange with the absorber plates?
