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Problem $13\mathrm{.}091-$ DEPENDENT MULTI$-$PART PROBLEM $-$ ASSIGN ALL THE PARTS

A thin aluminum sheet with an emissivity of $0\mathrm{.}5$ on both sides is placed between two very large parallel plates, which are maintained at uniform temperatures $T_1=909K$ and $T_2=650K$ and have emissivities ${}_1=0\mathrm{.}5$ and ${}_2=0\mathrm{.}8,$ respectively.