InterviewSolution
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InterviewSolution
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An aluminium vessel of mass `0.5kg` contains `0.2kg` of water at `20^(@)C` A block of iron of mass `0.2kg at 100^(@)C` is gently put into the water .Find the equilibrium temperature of the mixture,Specific beat capactities of aluminium , iron and water are `910 J kg^(-1)K^(-1) 470J kg^(-1)K^(-1) and 420J kg^(-1)K^(-1)` respectively |
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Answer» Correct Answer - C Given mass of aluminium `= 0.5 kg` Mass of water` = 0.2 kg` Mass of iron` = 0.2 kg` Tempetature of aluminium and water `= 20^(@) = 293^(@) K` Tempetature of iron `= 100^(@)C = 373 k` Specfic beat of AI ` = 910 J// kg-K` Heat gain ` = 0.5 xx 610 (T - 293) + 0.2 xx 4200 xx (T - 293)` `= (T- 293)(0.5 xx 910 + 0.2 xx 4200)` Heat lost `= 0.2xx 470 xx (373 - T)` We know heat gain = Head lost `rArr (T - 293)(0.5 xx 910 + 0.2 xx 4200)` `= 0.2 xx 470 xx (373 - T)` `rArr(T - 293)(455 + 840)= 94(373 - T)` `rArr (T - 293) (1295)/(94) = (273 - T) [(1295)/(94) =- 14]` ` (T - 293) xx 14 = 373 - T` `rArr 14T - 293 xx 14 = 373 - T` rArr 15T = 373 + 4102 = 4475` `rArr T = (4475)/(15) = 298 k ` ` :. T = (298 - 273)^(@)C = 25^(@)C` `:. ` The final temp ` = 25^(@)C` |
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