In filament lamps, the radiation of energy from a heated body is proportional to
1
\(T^{-4}_1 - T^{-4}_2\), where T1 and T2 are temperatures of the heated body and medium in °C
2
\(T^{-4}_1 - T^{-4}_2\), where T1 and T2 are temperatures of heated body and medium in °K
3
\(T^{4}_1 - T^{4}_2\), where T1 and T2 are temperatures of heated body and medium in °C
4
\(T^{4}_1 - T^{4}_2\), where T1 and T2 are temperatures of heated body and medium in °K