$A$ steam engine intakes $50 \, g$ of steam at $100^{\circ} C$ per minute and cools it down to $20^{\circ} C$. If the latent heat of vaporization of steam is $540 \, cal \, g^{-1}$,then the heat rejected by the steam engine per minute is .........$\times 10^{3} \, cal$.

How many $J$ of heat energy is required to convert $1\,g$ of ice at $-10^{\circ}C$ into steam at $100^{\circ}C$?

Fill in the blanks:
$(a)$ The $SI$ unit of the Stefan-Boltzmann constant is ...... .
$(b)$ In the thermal steady state of a rod,the temperature gradient is $5\,^{\circ}C/cm$ and the temperature of its hot end is $100\,^{\circ}C$. Then,at a distance of ........ $cm$ from the hot end,its temperature becomes $60\,^{\circ}C$.
$(c)$ At ...... temperature,the coefficient of volume expansion of water is zero.

Statement $(I)$: $A$ device in which heat measurement can be made is called a calorimeter.
Statement $(II)$: Skating is possible on snow due to the formation of water below the skates. Water is formed due to the increase of temperature and ice melts.
Statement $(III)$: Two bodies at different temperatures are mixed in a calorimeter. The total internal energy of the two bodies remains conserved.
Which of the following is correct?

$A$ beaker of height $H$ is made up of a material whose coefficient of linear thermal expansion is $3\alpha$. It is filled up to the brim by a liquid whose coefficient of thermal expansion is $\alpha$. If now the beaker along with its contents is uniformly heated through a small temperature $T$,the level of liquid will reduce by (given $\alpha T << 1$):

$A$ waterfall is $84 \ m$ high. If half of the potential energy of the falling water gets converted to heat,the rise in temperature of the water will be: (in $^\circ C$)