The ratio of energies of emitted radiation by a black body at 600 K and 900 K, when the surrounding temperature is 300 K, is:
E1E2=T41−T4sT42−T4s
=(600)4−(300)4(900)4−(300)4=316
A black body radiates energy at the rate of E W/m2 at a high temperature TK. When the temperature is reduced to T2K, the radiant energy will be