Solve the following problem:
Q: Heat transfer by radiation occurs between two large parallel plates, which are maintained at temperatures T1 and T2, with T1 > T2. To reduce the rate of heat transfer between the plates, it is proposed that they be separated by a thin shield that has different emissivities on opposite surfaces. In particular one surface has the emissivity es < 0.5,="" while="" the="" opposite="" surface="" has="" an="" emissivity="" of="" 2es.="">
(a) How should the shield be oriented to provide the larger reduction in heat transfer between the plates? That is should the surface of emissivity es, or that of emissivity 2es be oriented toward the plate at T1?
(b) What orientation will result in the larger value of the shield temperature Ts?