$A$ 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 specific heat of the human body is approximately the same as that of water,and the latent heat of evaporation of water at that temperature is about $580\; cal \;g^{-1}$.

  • A
    $9.5$
  • B
    $1.8$
  • C
    $6.8$
  • D
    $4.3$

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Similar Questions

$A$ block of ice at $-12^{\circ} C$ is slowly heated and converted into steam at $100^{\circ} C$. Which of the following curves best represents the event?

Work done (heat energy required) in converting $1\,g$ of ice at $-10\,^{\circ}C$ into steam at $100\,^{\circ}C$ is ......... $J$. (Take specific heat of ice $= 0.5\,cal/g^{\circ}C$,latent heat of fusion $= 80\,cal/g$,specific heat of water $= 1\,cal/g^{\circ}C$,latent heat of vaporization $= 540\,cal/g$,and $1\,cal = 4.2\,J$)

$A$ cube is subjected to a pressure $P$ on all its faces at a temperature of $0 \, ^\circ C$. By what temperature should the cube be heated so that it regains its original volume? Let the bulk modulus of the cube be $\beta$ and the coefficient of volume expansion be $\alpha$.

$A$ refrigerator converts $500\,g$ of water at $25\,^{\circ}C$ into ice at $-10\,^{\circ}C$ in $3\,hours\,40\,minutes$. The quantity of heat removed per minute is ........ $cal/\min$.
(Specific heat of water $= 1\,cal/g\,^{\circ}C$,Specific heat of ice $= 0.5\,cal/g\,^{\circ}C$,Latent heat of fusion $= 80\,cal/g$)

$A$ mass $m$ of material exists in its solid state at its melting temperature $0^\circ C$. The following processes occur to the material:
Process-$1$: An amount of thermal energy $Q$ is added to the material, and $\frac{2}{3}$ of the material melts.
Process-$2$: An identical additional amount of thermal energy $Q$ is added to the material, and the material is now a liquid at $40^\circ C$.
What is the ratio of the latent heat of fusion $(L)$ to the specific heat of the liquid $(s)$ for this material?

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