Heat is being supplied at a constant rate to a sphere of ice which is melting at the rate of $0.1 \,g/s$. It melts completely in $100 \,s$. The rate of rise of temperature of the resulting water thereafter will be ............ $^{\circ}C/s$.

$A$ calorimeter of mass $0.2 \ kg$ and specific heat $900 \ J/kg \cdot K$ contains $0.5 \ kg$ of a liquid of specific heat $2400 \ J/kg \cdot K$. Its temperature falls from $60^{\circ}C$ to $55^{\circ}C$ in one minute. The rate of cooling is ....... $J/s$.

The height of a waterfall is $84 \, m$. Assuming that the entire kinetic energy of falling water is converted into heat, the rise in temperature of the water will be $(g = 9.8 \, m/s^2, J = 4.2 \, J/cal, c = 1 \, cal/g^\circ C = 4200 \, J/kg^\circ C)$. (in $^\circ C$)

The thermo $e.m.f.$ of a thermocouple varies with the temperature $\theta$ of the hot junction as $E = a\theta + b\theta^2$ in volts,where the ratio $a/b$ is $700\,^{\circ}C$. If the cold junction is kept at $0\,^{\circ}C$,then the neutral temperature is:

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 $^{\circ} C$)

What is sublimation? Give names of sublimable substances.