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InterviewSolution
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A ice box of styrofoam (thermal conductivity = `0.01` J `ms^(-1)K^(-1)`) is used to keep liquid cool. It has a total wall area, including lid, of `10.8 m^(2)` and wall thickness of `2.0` cm. A bottle of water is placed in the box and filled with ice. If the outside temperature is `30^(@)C`, the rate of flow of heat into the box is (in `J//s)`A. 16B. 14C. 12D. 10 |
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Answer» Correct Answer - C Here `K=0.01 J ms^(-1)K^(-1), A=0.8 m^(2)`, `Delta x=2 cm =2xx10^(-2)m` `Delta T=30^(@)C, dQ//dt=?` `(dQ)/(dt) =KA (Delta T)/(Delta x)=0.01xx0.8xx(30)/(2xx10^(-2))` `=(8)/(1000)xx(30)/(2)xx100 =12 J//s` |
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