Regents Earth Science
John Dewey High School
Mr. Klimetz
Relative Humidity and Dewpoint Temperature
Reading the Earth Science Reference Tables XIII
Answer the following questions based on your interpretation of the Relative Humidity and Dewpoint Temperature charts of the Earth Science Reference Tables (page 12) as well as your class notes.


1.   A meteorologist records the following ground observations of the atmosphere at Syracuse:

Air Temperature: 20 degrees C
Dewpoint Temperature: 13 degrees C

The relative humidity of the air is most likely
a.  40%   b.  44%   c.  46%   d.  51%

2.   As the difference between the wet-bulb temperature and the dry-bulb temperature decreases, the
relative humidity
a.  increases   b.  decreases   c.  remains the same  

3.   As the dew point temperature of a given air mass approaches the dry-bulb temperature the wet-bulb
depression
a.  increases   b.  decreases   c.  remains the same  

4.   The interior of Mr. K's refrigerator is set to a temperature of -2 degrees C. He removes a bottle of
water from the refrigerator and sets it on a table in the outside yard where the air temperature is
24 degrees C. He observes that no condensation forms on the outside of the bottle. Which of the
following is the most likely relative humidity of the air in the yard?
a.  21%   b.  84%   c.  58%   d.  0%

5.   Which of the following pairs of statements is true when the wet-bulb depression is zero?
a.  the relative humidity is 100% and the air temperature equals the dewpoint temperature
b.  the relative humidity is 100% and the air temperature is less than the dewpoint temperature
c.  the relative humidity is less than 100% and the air temperature is less than the dewpoint temperature
d.  the relative humidity is greater than 100% and the air temperature equals the dewpoint temperature

6.   At which of the following pairs of values is an air mass perfectly dry and holds no water vapor?

  Relative Humidity (%)  Dewpoint Temperature (degrees C)

a.6518
b.2312
c.9014
d. 0 23

7.   A meteorologist swings a sling psychrometer and reads the following local observations of an air mass:

Dry-Bulb Temperature: 8 degrees C
Wet-Bulb Temperature: 5 degrees C

Which of the following data pairs is valid for the above observations?
a.  Relative humidity 1% and Dewpoint temperature 62 degrees C
b.  Relative humidity 62% and Dewpoint temperature 5 degrees C
c.  Relative humidity 1% and Dewpoint temperature 5 degrees C
d.  Relative humidity 62% and Dewpoint temperature 1 degree C





8.   Which of the following pairs of sling psychrometer readings indicates the dewpoint temperature is at the
freezing point of water?
a.  Dry-bulb: 6 degrees C; Wet-bulb:  4 degrees C
b.  Dry-bulb: 22 degrees C; Wet-bulb: 4 degrees C
c.  Dry-bulb: 26 degrees C; Wet-bulb: 13 degrees C
d.  Dry-bulb: 30 degrees C; Wet bulb:  15 degrees C