A solar collector is made of a cover plate then a 5 cm air gap and then an absorber plate with insulation on the back side of the absorber plate. The emissivity of both plates is given. The emissivity of the absorber plate is a function of wavelength and that graph is given. Both plates are diffuse.
What is the solar flux absorbed by the abdorber plate?
Given the temps of both plates, what is the rate of power lost from the absorber per unit area?