Question

A metal object weighing ${25}^{\circ }C$ is dropped in a calorimeter of mass $80$g and specific heat capacity of $1J{kg}^{-1}{K}^{-1}$, containing 100 g of water at ${40}^{\circ }C$. final temperature recorded was ${35}^{\circ }C$. find the specific heat capacity of metal object.
specific heat capacity of water $4200J{kg}^{-1}{K}^{-1}$

• A. $695J{kg}^{-1}{K}^{-1}$
• B. $4200.8J{kg}^{-1}{K}^{-1}$
• C. $3587.52J{kg}^{-1}{K}^{-1}$
• D. $5648J{kg}^{-1}{K}^{-1}$

Answer 1

Answer: (B)

$4200.8J{kg}^{-1}{K}^{-1}$

Let specific heat capacity of metal be $cJ{kg}^{-1}{K}^{-1}$
Heat energy taken by metal $=0.05\times c\times (35-25)=0.5cJ$
Heat given by calorimeter $=0.08\times 1\times (40-35)=0.4J$
Heat given by water $=0.1\times 4200\times (40-35)=2100J$
Total energy given by calorimeter and water $=0.4+2100=2100.4J$
If there is no loss of heat,Heat energy taken by metal = Total energy given by calorimeter and water
$0.5c=2100.4$
$c=2100.4/0.5$
$c=4200.8J{kg}^{-1}{K}^{-1}$