A solid graphite cube of edge 10cm is kept in a large evacuated enclosure whose walls are maintained at 300K. The cube itself is kept steady at 800K and behaves as an ideal black surface. Take the Stefan–Boltzmann constant as σ=5.67×10−8Wm−2K−4.
a. (i) Calculate the total power radiated per second from all the faces of the cube.
b. (ii) Determine the net heat lost by the cube in 2min due to thermal radiation under the above conditions.