Steam at $100\,^oC$ is passed into $20\, g$ of water at $10\,^oC$. When water acquires a temperature of $80\,^oC$, the mass of water present will be …….. $g$

[Take specific heat of water $= 1\, cal\, g^{-1}\,^oC^{-1}$ and latent heat of steam $= 540\, cal\, g^{-1}$]

The specific heat of water $=4200\, J\, kg ^{-1}\, K ^{-1}$ and the latent heat of ice $=3.4 \times 10^{5}\, J\, kg ^{-1}.$ $100$ grams of ice at $0^{\circ} C$ is placed in $200\, g$ of water at $25^{\circ} C$. The amount of ice that will melt as the temperature of water reaches $0^{\circ} C$ is close to (in $grams$) 

A steam engine intakes $50\, g$ of steam at $100^{\circ} C$ per minute and cools it down to $20^{\circ} C$. If 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.$

A $100 \,g$ of iron nail is hit by a $1.5\, kg$ hammer striking at a velocity of $60\, ms ^{-1}$. $…………^{\circ}C$ will be the rise in the temperature of the nail if one fourth of energy of the hammer goes into heating the nail .

[Specific heat capacity of iron  $=0.42\, Jg ^{-1}{ }\,^{\circ}C ^{-1}$ ]

Boiling water is changing into steam. Under this condition, the specific heat of water is