Chapter 13.1, Problem 15ES

One method for determining relative humidity is to wet the bulb of a thermometer, whirl it through the air, and then compare the thermometer reading with the actual air temperature. If the relative humidity is less than $100\%,$ the reading on the thermometer will be less than the temperature of the air. This difference in temperature is known as the wet-bulb depression. The accompanying table gives the relative humidity as a function of the air temperature and the wet-bulb depression. Use the table to complete parts (a)—(c).

(a) What is the relative humidity if the air temperature is $20°\text{C}$ and the wet-bulb thermometer reads $16°\text{C}?$

(b) Estimate the relative humidity if the air temperature is $25°\text{C}$ and the wet-bulb depression is $3.5°\text{C}.$

(c) Estimate the relative humidity if the air temperature is $22°\text{C}$ and the wet-bulb depression is $5°\text{ C}$ .