a horizontal plate is experiencing uniform irradiation on both the upper and lower surfaces. the ambient air temperature surrounding the plate is 290 k with a convection heat transfer coefficient of 30 w/m2-k. both the upper and lower surfaces of the plate have a radiosity of 4000 w/m2, and the plate temperature is maintained uniformly at 390 k. if the plate is not opaque and has an absorptivity of 0.527, determine the irradiation and emissivity of the plate.