A 3 cm diameter painted copper sphere is suspended in a large room where the walls and air are at 20°C (Fig XXXXXXXXXXIf the emissivity of the painted surface is 0.9, determine the net radiative heat...

A 3 cm diameter painted copper sphere is suspended in a large room where the walls and air are at 20°C (Fig. 13.63). If the emissivity of the painted surface is 0.9, determine the net radiative heat transfer rate from the surface and the rate of change of temperature of the sphere when its temperature is 600°C:

(a) Neglecting convection,

(b) Including convection.