ICSE Class 10 Physics 2016 Solved Paper

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Question : 39
Total: 73
A copper vessel of mass 100g contains 150g of water at 50C. How much ice is needed to cool it to 5C ?
Given :
Specific heat capacity of copper =0.4Jg1C1.
Specific heat capacity of water =4.2Jg1C1.
Specific latent heat of fusion of ice =336 Jg1
Solution:  
Heat given by water to reach 5C+ Heat given by copper vessel to reach 5C= Heat taken by ice to melt at 0C + Heat taken by melted ice to reach 5C
mct+mct=mL+mct
where t= change in temperature
[150×4.2×(505)]+[100×0.4× (505)]
=(m×336)+[m×4.2×(50)] (150×4.2×45)+(100×0.4×45)
=(m×336)+(m×4.2×5)
28350+1800=336m+21m
357m=30150
m=
30150
357

=84.45gm of ice.
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