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A liquid-nitrogen container is made of a...

A liquid-nitrogen container is made of a `1-cm` thick styrofoam sheet having thermal conductivity `0.025Js^(-1)m^(-1)C^(-1)` . Liquid nitrogen at ` 80K` is kept in it. A total area of `0.80m^(2)` is in contact with the liquid nitrogen. The atmospheric temperature is `300K` . Calculate the rate of heat flow from the atmosphere to the liquid nitrogen.

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The correct Answer is:
D
`d=1cm=0.01m A=0.2 m^(2)`
`(T_(1))=300^(@)C`,brgt``(T^(2))=80^(@)C`,brgt`K=0.025W//m-^(@)C`
`(Q)/(T)=(kA(T_1-T_2))/(l)`
`(0.025xx0.2xx(300-80))/0.01`
`=110 watt.`
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HC VERMA-HEAT TRANSFER-EXERCIESE
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  2. A liquid-nitrogen container is made of a 1-cm thick styrofoam sheet ha...

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  3. The normal body-temperature of a person is 97^(@)F . Calculate the rat...

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  4. A steam engine intakes 100 g of steam at 100^(o)C per minute and cools...

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  6. An icebox almost completely filled with ice at 0^(@)C is dipped into a...

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  7. A pitcher with 1-mm thick porous walls contain 10kg of water. ,Water c...

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  8. A steel frame (K=45Wm^(-1)C^(-1)) of total length 60cm and cross secti...

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  9. Water at 50^(@)C is filled in a closed cylindrical vessel of height 10...

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  10. The left end of a copper rod (length=20cm, Area of cross section=0.2cm...

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  11. The ends of a metre stick are maintain at 100^(@)C and 0^(@)C . One en...

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  12. A cubical box of volume 216cm^(3) is made up of 0.1cm thick wood, The ...

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  13. Figure shows water in a container having 2.0-mm thick walls made of a ...

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  14. On a winter day when the atmospheric temperature drops to -10^(@)C , i...

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  15. Consider the situation of the previous problem. Assume that the temper...

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  16. Three rods of lengths 20cm each and area of cross section 1cm^(2) are ...

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  17. A semicircular rods is joined at its end to a straight rod of the same...

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  18. A metal rod of cross sectional area 1.0cm^(2) is being heated at one e...

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