Question

$420J$ of energy supplied to $10gm$ of water will raise its temperature by

• A. $1^{o}C$
• B. ${4.2}^{o}C$
• C. ${10}^{o}C$
• D. ${42}^{o}C$

Answer 1

The correct option is C ${10}^{o}C$

Given - energy supplied $W=420J$ or $Q=W/J=420/4.2=100cal$ ,

$m=10g$ ,

now ,heat $Q$ supplied to a body of mass $m$ and of specific heat $c$ to increase its temperature by $\Delta \theta$ , is given by ,

$Q=mc\Delta \theta$ ,

we have , $c=1cal/g^{o}C,m=10g$ ,

hence , $100=10\times 1\times \Delta \theta$ ,

or $\Delta \theta =100/10={10}^{o}C$