Consider the very long, inclined black surfaces (A1, A2) maintained at uniform temperatures of T1 = 1000 K and T2 = 800 K.
(a) Determine the net radiation exchange between the surfaces per unit length of the surfaces.
(b) Consider the configuration when a black surface (A3), whose back side is insulated, is positioned along the dashed line shown.
Calculate the net radiation transfer to surface A2 per unit length of the surface and determine the temperature of the insulated surface A3.