The inner wall of an electric kiln is held at and radiates as a black surface

PHYSICS · Multi-part · Fermi University Physics · Quantum Mechanics · Origins of quantum theory · Origins of quantum theory

Thermal Physics, Ch Photons and phonons: blackbody radiation and the heat capacity of solids

Problem

The inner wall of an electric kiln is held at T=1500 KT = 1500\,\mathrm{K} and radiates as a black surface. A small viewing port of area A=0.020 m2A = 0.020\,\mathrm{m^2} is opened in the side, so that radiation from the cavity streams out through it. Treat the port as a black radiator at the wall temperature, and ignore the radiation coming back in from the cool room. ((a)) Find the radiated flux JJ from the wall, in W m−2\mathrm{W\,m^{-2}}. ((b)) Find the power streaming out of the port. ((c)) Find the frequency νmax⁡\nu_{\max} at which the spectral energy density inside the kiln peaks. Take σSB=5.670×10−8 W m−2 K−4\sigma_{\rm SB} = 5.670\times10^{-8}\,\mathrm{W\,m^{-2}\,K^{-4}}, kB=1.381×10−23 J K−1k_B = 1.381\times10^{-23}\,\mathrm{J\,K^{-1}} and h=6.626×10−34 J sh = 6.626\times10^{-34}\,\mathrm{J\,s}.

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