Chapter U3.18, Problem 9E

Interpretation Introduction

Interpretation :

This is to be explained why it is easy to get dehydrated when one exercises at 0°C with a relative humidity of 20 %.

Concept Introduction :

Saturation of air with water vapor depends on temperature. Relative humidity is the ratio of amount of water vapor to the amount of water vapor required for saturation.

Answer to Problem 9E

As presence of water vapor is only 20 % of the water vapor required to saturate the air, it is easy to get dehydrated when one is exercising at a temperature of 0°C.

Explanation of Solution

At a particular temperature certain volume of air needs some amount of water vapor to get saturated. If the relative humidity is low then it is clear that amount of water vapor is very low as compared to the water vapor required for saturation. As humidity is only 20 %, the air still has capacity to hold more water vapor. Now during the exercise, sweat will be generated which can be easily evaporated and the latent heat will be taken from the body.

Conclusion

Thus, it is easy to get dehydrated when one is exercising at a temperature of 0°C and a relative humidity is 20 %.