Hot coffee is contained in a cylindrical thermos botthe that is of length \(L=0.3 \mathrm{~m}\) and is lying on its side (horizontally).

The coffee container consists of a glass flask of diameter \(D_{1}=0.08 \mathrm{~m}\), separated from an aluminum housing of diameter \(D_{2}=0.09 \mathrm{~m}\) by air at atmospheric pressure. The outer surface of the flask and the inner surface of the housing are silver coated to provide emissivities of \(\varepsilon_{1}=\varepsilon_{2}=0.20\). If these surface temperatures are \(T_{1}=75^{\circ} \mathrm{C}\) and \(T_{2}=35^{\circ} \mathrm{C}\), what is the rate of heat loss from the coffee?

Transcribed Image Text:

D2 D Insulation strip -E2, T2 E, T Coffee L -Air space