A metallic ball and highly stretched spring are made of the same material and have the same mass. They are heated so that they melt, the latent heat required
are the same for Both
is greater for the ball
is greater for the spring
for the two may or may not be the same depending upon the metal
Dry ice is
The saturation vapour pressure of water at $100°C$ is ........ $mm$ of mercury
A thermally insulted vessel contains $150\, g$ of water at $0\,^oC$. Then the air from the vessel is pumped out a adiabatically. A fraction of water turns into ice and the rest evaporates at $0\,^oC$ itself. The mass of evaporated water will be closes to ....... $g$ (Latent heat of vaporization of water $= 2.10 \times10^6\, Jkg^{-1}$ and Laten heat of Fusion of water $ = 3.36 \times10^5\,Jkg^{-1}$ )
A child running a temperature of $101\,^{\circ} F$ is given an antipyrin (i.e. a medicine that lowers fever) which causes an increase in the rate of evaporation of sweat from his body. If the fever is brought down to $98\,^{\circ} F$ in $20$ minutes, what is the average rate of extra evaporation caused, by the drug (in $g/min$). Assume the evaporation mechanism to be the only way by which heat is lost. The mass of the child is $30\; kg$. The spectfic heat of human body is approximately the same as that of water, and latent heat of evaporation of water at that temperature is about $580\; cal \;g^{-1}$.
A copper block of mass $2.5\; kg$ is heated in a furnace to a temperature of $500\,^{\circ} C$ and then placed on a large ice block. What is the maximum amount of ice (in $kg$) that can melt? (Specific heat of copper $=0.39\; J g ^{-1} K ^{-1}$ ;heat of fusion of water $=335\; J g ^{-1})$