Area under \({e_\lambda } - \lambda \) curve represents the emissive power of body and emissive power \( \propto {T^4}\) (Hence area under \({e_\lambda } - \lambda \) curve) \( \propto {T^4}\)
==>\(\frac{{AT}}{{{A_{2000}}}} = {\left( {\frac{T}{{2000}}} \right)^4}\)
==> \(\frac{{16}}{1} = {\left( {\frac{T}{{2000}}} \right)^4}\)==> \(T = 4000K.\)
કારણ : હવા ઉષ્માનો સારો વાહક નથી.