Chapter 6.1, Problem 25E

Dewpoint. The dewpoint is the temperature at which moisture in the air condenses into liquid (dew). It is a function of air temperature t and relative humidity h. The table below shows the dewpoints for select values of t and h.

Air Temperature, $t\left(°\text{F}\right)$		Relative Humidity (%)
	20	40	60	80	100
70	29	44	55	63	70
80	35	53	65	73	80
90	43	62	74	83	90
100	52	71	84	93	100

a. What is the dewpoint when the air temperature is 80°F with a relative humidity of 60%?

b. What is the dewpoint when the air temperature is 90°F with a relative humidity of 40%?

The air feels humid when the dewpoint reaches about 60. If the air temperature is 100°F at what approximate relative humidity will the air feel humid?

Explain why the dewpoint is equal to the air temperature when the relative humidity is 100%.