A window of single glass 5 mm thick ( K = 1.0 W m − 1 K − 1 ) is replaced by two panes of 5 mm glass with a 10 mm air gap ( K ai r = 0.026 ). For the same temperature difference, find the ratio of t

Question

A window of single glass 5 mm thick ( K = 1.0 W m − 1 K − 1 ) is replaced by two panes of 5 mm glass with a 10 mm air gap ( K ai r ​ = 0.026 ). For the same temperature difference, find the ratio of the heat flow through the single window to that through the double window (one decimal).

TestHub · Accepted Answer

Resistance per unit area: single 1.0 0.005 ​ = 0.005 . Double: 2 × 0.005 + 0.026 0.010 ​ = 0.3946 . Ratio = 0.005 0.3946 ​ = 78.9 .

Physics - Heat & Thermo Question with Solution | TestHub

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