Two parallel concentric disks, 20 cm and 40 cm in diameter, are separated by a distance of 10 cm. The smaller disk (ε = 0.80) is at a temperature of 300°C. The larger disk (ε = 0.60) is at a temperature of 800°C.

(a) Calculate the radiation view factors.

(b) Determine the rate of radiation heat exchange between the two disks.

(c) Suppose that the space between the two disks is completely surrounded by a reflective surface. Estimate the rate of radiation heat exchange between the two disks.