Question

What is the amount of heat required to heat $1$kg of ice from $-{10}^o$C to $5^o$C?

Answer 1

Heat required to change the temperature of ice from $-10°Cto0°C=mc\Delta T={\theta }_1$ [specific heat capacity of i.e = $\frac{1}{2}cal/gm/°C$]

${\theta }_1=1000\times \frac{1}{2}\times 10$ = $5000calories$

Heat required to melt ice = $mL$ = ${\theta }_2$ [Latent heat of fusion = $80cal/gm$]

${\theta }_2=1000\times 80$ = $80000calories$

Heat required to convert temperature of water from $0°Cto5°C$ = $mc\Delta T={\theta }_3$

${\theta }_3=1000\times 1\times 5$ = $5000calories$

Total heat required $={\theta }_1+{\theta }_2+{\theta }_3$

$=5000+8000+5000=90000calories$