In the arrangement shown, the lower disk has a diameter of 30 mm and a temperature of 500 K. The upper surface, which is at 1000 K, is a ring-shaped disk with inner and outer diameters of 0.15 m and 0.2 m. This upper surface is aligned with and parallel to the lower disk and is separated by a distance of 1m. Assuming both surfaces to be blackbodies, calculate their net radiative heat exchange.

D- 02 m +D, = 0.15 m Ring-shaped disk, A. T= 1000 K Disk, A. T = 500 K