emissive power

The emissive power of a blackbody is P. If its absolute temperature is doubled, the emissive power becomes

The total emissive power of a surface is $$500$$ $$W/{m^2}$$ at a temperature $${T_1}$$ and $$1200$$ $$W/{m^2}$$ at a temperature $${T_2}$$, where the temperatures are in Kelvin. A...