Chapter 14.2, Problem 2RQ

Interpretation Introduction

Interpretation: Whether dipping hand in water and then removing it in air or dipping hand in methyl alcohol and then removing it in air is expected to feel cooler is to be explained.

Concept introduction: After dipping the hand in a liquid and then removing it in air, it feels cold because of evaporation of liquid from the surface of skin.

Answer to Problem 2RQ

In case of dipping hand in methyl alcohol and then removing it in air, one’s hand would be expected to feel cooler.

Explanation of Solution

After dipping the hand in a liquid and then removing it in air, it feels cool because of evaporation of liquid from the surface of skin. Evaporation leads to the removal of heat from the surface of the skin. Out of water and methyl alcohol, methyl alcohol is more volatile and thus evaporates faster than water. So it is expected that one would feel cooler when a hand is dipped in it and then removed in air.

Conclusion

In case of dipping hand in methyl alcohol and then removing it in air, one’s hand would be expected to feel cooler.