An opaque surface, 2 m by 2 m, is maintained at 400 K and is exposed to irradiation with G = 1200 W/m2. The irradiation has the spectral distribution of a blackbody at 4000 K. The surface is diffuse and its spectral absorptivity is ai = 0.3 = 0.5 = 0.75 = 0.9 0< < 0.5 um 0.5 um << 1.0 um 1.0 um < 2.0 um > 2.0 um Determine the absorbed radiation, the emissive power, and the net radiation heat transfer.