The heat required to change $1 \,kg$ of ice at $-8^{\circ} C$ into water at $20^{\circ} C$. at $1 \,atm$ of pressure, is closest to .............$\,kJ$ (Assume that ice has a specific heat capacity $2.1 \,kJ / kg / K$. water has a specific heat capacity $4.2 \,kJ / kg / K$, and latent heat of fusion of ice is $333 \,kJ / kg$ )

A tap supplies water at $10\,^oC$ and another tap at $100\,^oC$. .......... $kg$ hot water must be taken so that we get $20\, kg$ water at $35\,^oC$ ?

A block of mass $2.5\,\, kg$ is heated to temperature of $500^o C$ and placed on a large ice block. ......... $kg$ is the maximum amount of ice that can melt (approx.). Specific heat for the body $= 0.1 Cal/gm^o C$.

One kilogram of ice at $0°C$ is mixed with one kilogram of water at $80°C.$ The final temperature of the mixture is........ $^oC$

$($Take : specific heat of water$ = 4200\,J\,k{g^{ - 1}}\,{K^{ - 1}}$, latent heat of ice $ = 336\,kJ\,k{g^{ - 1}})$

$20\, gm$ of boiling water is poured into an ice-cold brass vessel (specific heat $0.1\, cal/gm-\,^oC$) of mass $100\, gm$. The resulting temperature is ........ $^oC$

A water cooler of storage capacity $120$ litres can cool water at a constant rate of $P$ watts. In a closed circulation system (as shown schematically in the figure), tr e wat'r from the cooler is used to cool an external device that generates constantly $3 \mathrm{~kW}$ of heat (thermal load). The temperature of water fed into the device cannot exceed $30^{\circ} \mathrm{C}$ and the e.tire stored $120$ litres of water is initially cooled to $10^{\circ} \mathrm{C}$. The entire system is thermally insulat $\mathrm{d}$. The minimum value of $P$ (in watts) for which the device can be operated for $3$ hours is

(Specific heat of water is $4.2 \mathrm{~kJ}^{-1} \mathrm{~kg}^{-1}$ and the density of water is $10.$) $0 \mathrm{k}^2 \mathrm{~m}^{-3}$ )