Work out stefan boltzmann law instantly with clear inputs, formula shown and shareable results.
The Stefan-Boltzmann law says radiated power per unit area is e.sigma.T^4. A 2 m2 surface at 500 K with emissivity 0.9 radiates about 6.4 kW. The fourth power dominates everything: doubling absolute temperature multiplies emission sixteenfold, which is why radiation overtakes convection in furnaces.
Stefan-Boltzmann law
P = e sigma A T^4, sigma = 5.6704e-8 W/(m2 K4)
Net exchange
P(net) = e sigma A (T^4 - T(surroundings)^4)
Absolutely - the fourth power makes any offset scale meaningless. Using Celsius would be badly wrong.
About 0.95 for matt paint, brick and skin, 0.9 for oxidised metal, and as low as 0.03 for polished aluminium.