Chapter 12, Problem 12.51P

The spectral reflectivity distribution for white paint (Figure 12.22) can be approximated by the following stair-step function

A small flat plate coated with this paint is suspended inside a large enclosure, and its temperature is maintained at 400K. The surface of the enclosure is maintained at $3000K$ and the spectral distribution of its emissivity has the following characteristics:

(a) Determine the total emissivity, $\epsilon$ , of the enclosure surface.

(b) Determine the total emissivity, $\epsilon$ , and absorptivity, $\alpha$ , of the plate.