$A$ calorimeter has a water equivalent of $5 \times 10^{-3} \ kg$ and contains $25 \times 10^{-3} \ kg$ of water. It takes $3 \ minutes$ to cool from $28^{\circ}C$ to $21^{\circ}C$. When it is filled with turpentine oil,it takes $2 \ minutes$ to cool from $28^{\circ}C$ to $21^{\circ}C$. The specific heat of turpentine oil is ..... $cal/g^{\circ}C$.

$A$ stationary object at $4^{\circ}C$ and weighing $3.5\, kg$ falls from a height of $2000\, m$ on a snow mountain at $0^{\circ}C$. If the temperature of the object just before hitting the snow is $0^{\circ}C$ and the object comes to rest immediately $(g = 10\, m/s^2)$ and (latent heat of ice $= 3.5 \times 10^5\, J/kg$),then the amount of ice that will melt is:

For a copper-iron $(Cu-Fe)$ couple,the thermo $e.m.f.$ (temperature of cold junction $= 0\,^{\circ}C$) is given by $E = (14\theta - 0.02\theta^2)\,\mu V$. The neutral temperature will be

An earthen pitcher used in summer cools water in it essentially by evaporation of water from its porous surface. If a pitcher carries $4 \,kg$ of water and the rate of evaporation is $20 \,g$ per hour,the temperature of water in it decreases by $\Delta T$ in two hours. The value of $\Delta T$ is close to ........... $^{\circ} C$ (ratio of latent heat of evaporation to specific heat of water is $540^{\circ} C$).

Find the difference in temperature between the water at the top and the bottom of a $20 \ m$ high waterfall, assuming $10 \%$ of the energy of the fall is spent in heating the water. [Use specific heat capacity of water $= 4000 \ J \ kg^{-1} K^{-1}$ and $g = 10 \ m/s^2$]. (in $^{\circ} C$)

$A$ thermally insulated vessel contains $150\, g$ of water at $0\, ^oC$. Then the air from the vessel is pumped out adiabatically. $A$ fraction of water turns into ice and the rest evaporates at $0\, ^oC$ itself. The mass of evaporated water will be closest to ....... $g$ (Latent heat of vaporization of water $= 2.10 \times 10^6\, J/kg$ and Latent heat of fusion of water $= 3.36 \times 10^5\, J/kg$).