An opaque surface, $2$ m $2$ m$,$ is maintained at $350$ K and is simultaneously exposed

to solar irradiation with $!=1200/".$ The surface is diffuse and its spectral absorptivity is

$=0,0\mathrm{.}8,0,$ and $0\mathrm{.}9$ for $0$ $0\mathrm{.}6$ m$,0\mathrm{.}6$ m $<$ $1\mathrm{.}2$ m$,1\mathrm{.}2$ m $<$ $2$ m$,$

and $>2$ m$,$ respectively. Determine the: $(1)$ absorbed irradiation, $(2)$ emissive power, $(3)$

radiosity, and $(4)$ net rate of radiation heat transfer from the surface