Question

How much water (in liters) has the camel to drink to keep its body temperature 34 \[^\circ }C\] by evaporation of sweat during the day (12 h) instead of rising to 40 \[^\circ}C\]?
A. 41.4 L
B. 3.45 L
C. 414 L
D. 34.5 L

Answer 1

Hint: Camels require very little water because they are able to tolerate relatively large changes in their body temperature. If we compare humans and the camels then we came to know that humans keep the body temperature almost constant allowing variation of one or two degree but the camels on the other hand a dehydrated camel permits its body temperature to drop to 34 \[^{\circ} C\] overnight and rise to 40 \[^^{\circ}C\] during the day.

Complete step by step solution:
Using principle of calorimetry, energy released= energy required for phase change
\[{{M}_{c}}{{C}_{c}}\Delta T={{m}_{w}}L\] where \[{{M}_{c}}\] is the mass of the camel, it is not given in the question, assuming it to be 400 kg. Also, \[{{C}_{c}}\] for camels is 3480 J/kgK. For water L= \[242\times {{10}^{4}}J/kg\]
Required change in temperature, \[\Delta T\]= 40-34= 6\[^{\circ}C\]
Putting the values, we get,
${{M}_{c}}{{C}_{c}}\Delta T={{m}_{w}}L \\
\Rightarrow {{m}_{w}}=\dfrac{{{M}_{c}}{{C}_{c}}\Delta T}{L} \\
\Rightarrow {{m}_{w}}=\dfrac{400\times 3480\times 6}{242\times {{10}^{4}}} \\
\therefore {{m}_{w}}=3.45l $
Thus, it should store around 3.45 l from water.

Hence, option B is the correct answer.

Note: Also, it was not mentioned the units of temperature so we didn’t convert the temperature from degree Celsius to degree kelvin. Temperature is the measure of hotness or coldness of the body. Whenever we are making a difference, we do not have to worry about the temperature units. But if someplace we have to take only temperature, then we should put the units in Kelvin and not in degree Celsius.