Two very large parallel plates are maintained at uniform temperatures T1 = 750 K and T2 =...

Two very large parallel plates are maintained at uniform temperatures T1 = 750 K and T2 = 500 K and have emissivities ε1 = 0.85 and ε2 = 0.7, respectively. If a thin aluminum sheet with the same emissivity on both sides is to be placed between the plates in order to reduce the net rate of radiation heat transfer between the plates by 90 percent, the emissivity of the aluminum sheet must be

(a) 0.07

(b) 0.10

(c) 0.13

(d) 0.16

(e) 0.19