Q$\mathrm{.}48$ Consider an enclosure consisting of two large, parallel, opaque plates. The plate surfaces aregray and are kept at uniform temperatures T$$ and T; and have emissivities E and & $.$Calculate the net radiation flux q$1-2$ leaving suuface $1($in W$/$m$)$ for T$=800$ K$,$ T$)=600$ Kand $=$ & $=0\mathrm{.}8.$The value of the Stefan$-$Boltzmann constant is o $=5\mathrm{.}67$ x $10-8$ W$/$m$^2$ K$*)$Choose the option closest to the answer$($A$)9000($C$)10500($B$)12000($D$)13590$