$2\;gm$ of steam condenses when passed through $40gm$ of water initially at $25^oC.$ The condensation of steam raises the temperature of water to $54.3^oC.$ What is the latent heat of steam ........... $cal/g$
$540$
$536$
$270$
$480$
A solid substance is at $30°C$. To this substance heat energy is supplied at a constant rate. Then temperature versus time graph is as shown in the figure. The substance is in liquid state for the portion (of the graph)
When $M_1$ gram of ice at $-10\,^oC$ (specific heat $= 0.5\, cal\, g^{-1}\,^oC^{-1}$) is added to $M_2$ gram of water at $50\,^oC$, finally no ice is left and the water is at $0\,^oC$. The value of latent heat of ice, in $cal\, g^{-1}$ is
Values for latent heat in Column$-\,I$ and its values are given in Column$-\,II$. Match the followings :
Column $-\,I$ | Column $-\,II$ |
$(a)$ Latent heat of vaporization $L_V$ | $(i)$ $22.6\, \times \,{10^5}\,J\,/kg$ |
$(b)$ Latent heat of fusion $L_f$ | $(ii)$ $33.3\, \times \,{10^5}\,J\,/kg$ |
$(iii)$ $3.33\, \times \,{10^5}\,J\,/kg$ |
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 $580\; cal \;g^{-1}$.
Why skating is possible on ice ?