$A$ thermocouple develops $40\,\mu V/K$. If the hot and cold junctions are at $40\,^{\circ}C$ and $20\,^{\circ}C$ respectively,then the emf developed by a thermopile using $150$ such thermocouples in series shall be ............... $mV$.

$ 1 \text{ g} $ of ice is mixed with $ 1 \text{ g} $ of steam. At thermal equilibrium,the temperature of the mixture is (in $^{\circ} C$)

If $1\; g$ of steam at $100^{\circ}C$ is mixed with $1\; g$ of ice at $0^{\circ}C$,then the resultant temperature of the mixture is ........ $^{\circ}C$.

Which form of heat was believed in before the modern time?

Which of the following best represents the temperature versus heat supplied graph for water, in the range of $-20^{\circ}C$ to $120^{\circ}C$?

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 $^{\circ} C$)