Deck 4: Atmospheric Humidity

Question 1

The air's moisture content can be described by measuring the pressure exerted by the water vapor in the air.

Answer 1

True

Question 2

A region can have a high specific humidity and low relative humidity because large amounts of water vapor in the air and very high air temperatures will cause the specific humidity to be high,but the relative humidity to be low.

Answer 2

True

Question 3

Condensation occurs primarily when air is cooled,because as temperature drops the speed of the water molecules increases.

Answer 3

False

Question 4

During the winter,high relative humidity can irritate the mucus membranes in the nose and throat.

Question 5

Under saturated conditions,for every molecule that evaporates,one must condense,and no net loss of liquid or vapor molecules results.

Question 6

Condensation differs from precipitation,because during precipitation water vapor is removed from the atmosphere,whereas during condensation solid or liquid water is removed from the atmosphere.

Question 7

Water in a glass will evaporate more quickly on a windy,warm,dry summer day than on a calm,cold,dry winter day.

Question 8

Nighttime temperatures rarely drop below the dew point temperature because at saturation,latent heat of condensation is released into the air.

Question 9

The dew point temperature is a measure of the total amount of water vapor in the air.

Question 10

Saturation is more likely to occur in cool air than in warm air.

Question 11

A strand of human hair is known to increase by 2.5 percent as the relative humidity increases from 0 to 100 percent.

Question 12

When the air temperature increases,the saturation vapor pressure decreases.

Question 13

Days with temperatures above 90 degrees Fahrenheit and above 90 percent humidity are common in the southern United States.

Question 14

The relative humidity is often near 100 percent in polar regions.

Question 15

Plants give up moisture by a process called perspiration.

Question 16

Saturation vapor pressure primarily depends upon air pressure.

Question 17

If the amount of water vapor in a descending atmospheric air parcel remains constant,the specific humidity also remains constant.

Question 18

A sling psychrometer directly measures the relative humidity.

Question 19

The specific humidity and mixing ratio of an air parcel remain constant as long as water vapor is not added to or removed from the parcel.

Question 20

Comparing the three phases of water,molecules in the solid phase (ice)have the highest vibrational speed,and molecules in the gaseous phase (water vapor)have the slowest vibrational speeds.

Question 21

Which of the following always decreases in a rising parcel of air?​

A)relative humidity
B)absolute humidity
C)​specific humidity
D)​mixing ratio
E)​dew point

Question 22

At what time of day is the relative humidity normally at a minimum?​

A)when the air temperature is highest
B)just before sunrise
C)​about midnight
D)​when the air temperature is lowest
E)​at sunset

Question 23

Suppose it is snowing outside and the air is saturated.The air temperature and dew point are both 15°F,and the actual vapor pressure is 3 mb.If this air is brought indoors and warmed to 75°F,what would the relative humidity of this air be,assuming that its moisture content does not change? (The saturation vapor pressure at 75°F is 30 mb).​

A)5 percent
B)10 percent
C)​30 percent
D)​50 percent
E)​100 percent

Question 24

The ratio of the mass of water vapor in a given volume (parcel)of air to the mass of the remaining dry air describes the​

A)absolute humidity.
B)mixing ratio.
C)​relative humidity.
D)​dew point.
E)​water vapor content.

Question 25

The density of water vapor in a given parcel of air is represented by the​

A)absolute humidity.
B)relative humidity.
C)​mixing ratio.
D)​specific humidity.
E)​saturation vapor pressure.

Question 26

Which of the following will increase in a rising parcel of air?​

A)saturation vapor pressure
B)relative humidity
C)​mixing ratio
D)​air temperature
E)​air pressure

Question 27

A high water vapor pressure indicates a(n)​

A)relatively large number of water vapor molecules in the air.
B)relatively small number of water vapor molecules in the air.​
C)​relatively high rate of evaporation.
D)​abundant supply of condensation nuclei in the air.
E)​relatively high rate of precipitation.

Question 28

Evaporative coolers are primarily used in climates where the summers are​

A)hot and humid.
B)hot and dry.
C)​cold and humid.
D)​cold and dry.
E)​moderate.

Question 29

If water vapor comprises 3.5 percent of an air parcel whose total pressure is 1000 mb,the water vapor pressure would be​

A)1035 mb.
B)35 mb.
C)​350 mb.
D)​965 mb.
E)​3500 mb.

Question 30

The time of day when the relative humidity reaches a maximum value is usually​

A)at the time when the air temperature is highest.
B)in the middle of the afternoon.
C)​at the time when the air temperature is lowest.
D)​just before sunrise.
E)​about midnight.

Question 31

If the air temperature increased,with no addition or removal of water vapor,the actual vapor pressure would​

A)increase.
B)decrease.
C)​stay the same.
D)​become greater than the saturation vapor pressure.
E)​become less than the saturation vapor pressure.

Question 32

What happens when air is saturated?​

A)The air temperature equals the wet-bulb temperature.
B)The relative humidity is nonetheless less than 100 percent.
C)​The air temperature is higher than the dew point temperature.
D)​An increase in temperature will cause condensation to occur.
E)​The temperature increases.

Question 33

As the air temperature increases,the air's capacity for water vapor​

A)increases.
B)decreases.
C)​remains constant.
D)​is unrelated to air temperature and can either increase or decrease.
E)​drops by 50%.

Question 34

Which of the following will increase the relative humidity in a home during the winter?​

A)increasing the thermostat setting
B)increasing the temperature of the air inside the home
C)​sealing the house against drafts
D)​taking a shower and letting the air circulate through the home
E)​turning on the oven

Question 35

If the air temperature remains constant,evaporating water into the air will ____ the dew point and ____ the relative humidity.​

A)increase;increase
B)increase;decrease
C)​decrease;increase
D)​decrease;decrease
E)​not change;not change

Question 36

The percentage of water vapor present in the air compared to that required for saturation is the​

A)mixing ratio.
B)absolute humidity.
C)​dew point.
D)​relative humidity.
E)​specific humidity.

Question 37

The total mass of water vapor stored in the atmosphere at any moment is about ____ of the world's supply of precipitation.​

A)1 day
B)1 week
C)​1 month
D)​1 year
E)​10 days

Question 38

Suppose the dew point of cold outside air is the same as the dew point of the air indoors.If the door is opened and cold air replaces some of the warm air,then the new relative humidity indoors would be​

A)lower than before.
B)higher than before.
C)​the same as before.
D)​impossible to tell from the information given
E)​zero

Question 39

What will occur if a glass of water at a stable temperature is surrounded by saturated air?

A)The level of the water in the glass would slowly decrease.
B)The water's temperature would slowly increase.
C)​The level of the water in the glass would not change.
D)​The water's temperature would slowly decrease.
E)​The level of the water in the glass would slowly increase.

Question 40

The temperature at which water boils depends mainly on​

A)air temperature
B)relative humidity
C)​air pressure
D)​air density
E)​the specific heat of air

Question 41

In the solid state called ice,the shape and charge of water molecule helps arrange the molecules into ____ crystals.​

A)three-sided (trigonal)
B)four-sided (tetragonal)
C)​five-sided (pentagonal)
D)​six-sided (hexagonal)
E)​eight-sided (octagonal)

Question 42

Condensation is most likely to happen when air ____ and the speed of the water vapor molecules ____.​

A)remains the same temperature;decreases
B)cools: increases
C)​cools;decreases
D)​warms;increases
E)​warms;decreases

Question 43

The temperature to which air must be cooled in order to become saturated is the​

A)minimum temperature.
B)dew point temperature.
C)​wet-bulb temperature.
D)​freezing point.
E)​maximum temperature.

Question 44

The mass of water vapor in a given volume of air is called ____.​

A)absolute humidity
B)relative humidity
C)​mixing ratio
D)​specific humidity
E)​dew point

Question 45

On a warm and windy day evaporation will be ____.​

A)low
B)medium
C)​the same as any other day
D)​zero
E)​high

Question 46

Sun's energy transforms enormous quantities of liquid water into water vapor in a process called ____.​

A)transformation
B)perspiration
C)​precipitation
D)​evaporation
E)​condensation

Question 47

____ law of partial pressure describes that the total pressure inside an air parcel is equal to the sum of all pressures of the individual gases present in the air parcel.​

A)Hilton's
B)Dalton's
C)​Dayton's
D)​Hillary's
E)​Ryan's

Question 48

Which of the following is the BEST indicator of the actual amount of water vapor in the air?​

A)air temperature
B)saturation vapor pressure
C)​relative humidity
D)​dew point temperature
E)​mixing ratio

Question 49

The oceans occupy over ___ percent of Earth's surface.​

A)50
B)60
C)​70
D)​80
E)90

Question 50

This instrument uses wet-bulb and dry-bulb temperature to obtain relative humidity:​

A)infrared hygrometer
B)sling psychrometer
C)​hair hygrometer
D)​electrical hygrometer
E)​mechanical hygrometer

Question 51

The average specific humidity is ____ in the warm,muggy tropics.As we move away from the tropics,it ____.​

A)lowest;increases
B)highest;increases
C)​intermediate;decreases
D)​lowest;decreases
E)​highest;decreases

Question 52

Evaporation and transpiration from continental areas amount to only about ____ percent of the nearly 1.5 billion gallons of water vapor that annually evaporate into the atmosphere.​

A)15
B)20
C)​25
D)​30
E)​35

Question 53

The hot,desert air of the Sahara often contains ____ water vapor than the cold,polar air farther north,therefore has a ____ specific humidity.​

A)less;lower
B)less;higher
C)​less;similar
D)​more;higher
E)​more;lower

Question 54

The partial pressure of water vapor is called the ____.​

A)real vapor pressure
B)true vapor pressure
C)​actual vapor pressure
D)​actual water pressure
E)​true liquid pressure

Question 55

The lowest temperature that can be attained by evaporating water into the air is known as the​

A)heat index.​
B)minimum temperature.
C)​wet-bulb temperature.
D)​frost point.
E)​wind chill temperature.

Question 56

If all of Earth's water vapor were to suddenly condense and fall as rain,it would be enough to cover the entire globe with ____ of water.​

A)5 cm (2 inches)
B)100 m
C)​2.5 cm (1 inch)
D)​1000 m
E)​10 cm (4 inches)

Question 57

As the difference between the air temperature and the dew point increases,the relative humidity​

A)increases.
B)decreases.
C)​remains constant at a value less than 100 percent.
D)​remains constant and equal to 100 percent.
E)​drops to zero.

Question 58

In the liquid state,water molecules are ____ in the gaseous state.​

A)further apart than
B)the same distance apart as
C)​double the distance apart as
D)​three times the distance apart as
E)​closer together than

Question 59

The instrument that measures humidity by measuring the amount of radiant energy absorbed by water vapor is the​

A)electrical hygrometer.
B)infrared hygrometer.
C)​sling psychrometer.
D)​hair hygrometer.
E)​dew cell.

Question 60

The relationship between the mass of water vapor in an air parcel and the mass of all air in the same parcel (including vapor)is called ____.​

A)specific humidity
B)relative humidity
C)​absolute humidity
D)​dew point
E)​mixing ratio

Question 61

The primary factors that influence evaporation are ____________________,____________________,and ____________________.

Question 62

The heat index (HI)is used by the National Weather Service,and combines ____ with ____ to determine an apparent temperature.​

A)dew point temperature;mixing ratio
B)mixing ratio;saturation vapor pressure
C)​actual vapor pressure;specific humidity
D)​air temperature;relative humidity
E)​air temperature;specific humidity

Question 63

When both the air temperature and relative humidity are high and the air is nearly saturated with water vapor,body moisture does not readily ____.​

A)transpire
B)perspire
C)​saturate
D)​condense
E)​evaporate

Question 64

A temperature of 90 degrees Fahrenheit and a relative humidity of 90 percent can occur only if the ____ is incredibly high,which is only very rarely observed in the United States.​

A)mixing ratio
B)apparent temperature
C)​heat index
D)​saturation vapor pressure
E)​dew point temperature

Question 65

Instruments that measure humidity are called ____.​

A)psychrometers
B)thermometers
C)​hygrometers
D)​dew cells
E)​liquid-in-glass thermometers

Question 66

Saturation vapor pressure depends primarily on ____.​

A)the mixing ratio
B)altitude
C)​air pressure
D)​the dew point temperature
E)​air temperature

Question 67

The higher the temperature of a gas,the ____________________ its molecules move.

Question 68

Suppose saturated polar air has an air temperature and dew point of -10°C,and unsaturated desert air has an air temperature of 35°C and a dew point of 10°C.The desert air contains ____________________ water vapor and has a(n)____________________ relative humidity than the polar air.

Question 69

The psychrometer is used to obtain ____ and ____.​

A)dew point;relative humidity
B)apparent temperature;heat index
C)​air pressure;saturation vapor pressure
D)​absolute humidity;actual temperature
E)​dew point temperature;specific humidity

Question 70

When the air temperature is below freezing,the saturation vapor pressure over water is ____________________ than the saturation vapor pressure over ice.

Question 71

The temperature difference between the dry bulb and the wet bulb is known as the ____.​

A)dry-bulb depression
B)wet-bulb depression
C)​dry-bulb inclination
D)​wet-bulb inclination
E)​bulb depression

Question 72

The cycle of moving and transforming water molecules from liquid to vapor and back to liquid again is called the ____________________.

Question 73

In summer across North America,____ vapor pressures are experienced over the drier Great Basin,especially Nevada;in winter,____ values exist over the northern Great Plains into Canada.​

A)the lowest;the lowest
B)the highest;the highest
C)​the lowest;the highest
D)​the highest;the lowest
E)​intermediate;intermediate

Question 74

The ____________________ temperature is the temperature to which air would have to be cooled (with no change in air pressure or moisture content)for saturation to occur.

Question 75

During the great Chicago heat wave of July 1995 the afternoon air temperature reached 106 degrees Fahrenheit at Midway Airport,followed by an overnight low temperature of only 84 degrees Fahrenheit.Many residents either had no air conditioning or could not afford to use it.More than ____ deaths occurred over five days.​

A)35
B)70
C)​350
D)​700
E)​3500

Question 76

Hot and humid summer days usually feel ____________________ than hot and dry summer days.

Question 77

As the air temperature increases,with no addition of water vapor to the air,the relative humidity will ____________________.

Question 78

The ____ determines the amount of water vapor in the air by measuring the air's actual water vapor pressure.​

A)aspirated psychrometer
B)hair hygrometer
C)​sling psychrometer
D)​dew-point hygrometer
E)​dew cell

Question 79

If very cold air is brought indoors and warmed with no change in its moisture content,the saturation vapor pressure of this air will ____________________ and the relative humidity of this air will ____________________.

Question 80

Frozen clothes "dry" outside in subfreezing weather by a process called ____________________.