A solid sphere of diameter 10 cm is heated to 1000°C and suspended in a room whose walls are at 30°C. Compute the following:
(i) Rate of heat transfer due to radiation only neglecting other losses.
(ii) Time taken by the sphere to cool to 500°C. Assuming Emissivity for the sphere = 0.1 density 8.68 gm/cc. Sp. Heat 0.098 J/kg K.