$A$ 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 .........$\times 10^{3} \, cal$.

Two identical balls,$A$ and $B$,of uniform composition and initially at the same temperature,each absorb exactly the same amount of heat. $A$ is hanging from the ceiling while $B$ rests on the horizontal floor in the same room. Assuming no subsequent heat loss by the balls,which of the following statements is correct about their final temperatures,$T_A$ and $T_B$,once the balls have reached their final state?

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

Heat needed to convert $1 \ kg$ of ice at $0^{\circ} C$ to steam at $100^{\circ} C$ is

$A$ thin-walled cylindrical metal vessel with a linear coefficient of expansion $10^{-3} \ ^\circ C^{-1}$ contains benzene with a volume expansion coefficient of $10^{-3} \ ^\circ C^{-1}$. If the vessel and its contents are heated by $10 \ ^\circ C$,the pressure due to the liquid at the bottom:

The heat extracted out of $x \ \text{g}$ of water initially at $50^\circ \text{C}$ to cool it down to $0^\circ \text{C}$ is sufficient to evaporate $(1000 - x) \ \text{g}$ of water also initially at $50^\circ \text{C}$. The value of $x$ (closest integer) is . . . . . . . (Take latent heat of water $L = 2256 \ \text{kJ/kg}$, specific heat capacity of water $c = 4200 \ \text{J/kg}\cdot \text{K}$)