According to the Stefan-Boltzmann law, the rate of heat radiated per unit area by a black body is directly proportional to the fourth power of its absolute temperature, i.e., $E \propto T^4$. Given: Initial temperature, $T_1 = 227^\circ\text{C} = 227 + 273 = 500 \text{ K}$ Initial rate of heat radiated, $E_1 = 7 \text{ cal cm}^{-2}\text{s}^{-1}$ Final temperature, $T_2 = 727^\circ\text{C} = 727 + 273 = 1000 \text{ K}$ Therefore, the ratio of the new rate of heat radiated ($E_2$) to the initial rate ($E_1$) is: $\frac{E_2}{E_1} = \left(\frac{T_2}{T_1}\right)^4 = \left(\frac{1000}{500}\right)^4 = 2^4 = 16$ $E_2 = 16 \times E_1 = 16 \times 7 = 112 \text{ cal cm}^{-2}\text{s}^{-1}$