Hot coffee is contained in a cylindrical thermos bottle that is of length L = 0.3 m and is lying on its side (horizontally). The coffee container consists of a glass flask of diameter D₁ = 0.07 m, separated from an aluminum housing of diameter D₂ = 0.08 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 ?₁ = ?₂ = 0.25. If these surface temperatures are T₁ = 75? C and T₂ = 35?C, what is the heat loss from the coffee?

Transcribed Image Text:

Coffee D, D Air space Insulation strip