The spectral emissivity of an opaque, diffuse surface is as shown.

(a) If the surface is maintained at 1000 K, what is the total, hemispherical emissivity?

(b) What is the total, hemispherical absorptivity of the surface when irradiated by large surroundings of emissivity 0.8 and temperature 1500 K?

(c) What is the radiosity of the surface when it is maintained at 1000 K and subjected to the irradiation prescribed in part (b)?

(d) Determine the net radiation flux into the surface for the conditions of part (c).

(e) Plot each of the parameters featured in parts (a)-(d) as a function of the surface temperature for 750

1.0 (um) 2.