Calculate the net radiation transfer to surface a2 per unit

Question

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.