CHAPTER 5
AIR PRESSURE
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MULTIPLE CHOICE QUESTIONS
1.
a.
b.
c.
d.
e.
The magnitude of pressure exerted by the gas molecules composing air depends on
the mass of the air molecules.
the pull of gravity.
the kinetic energy of air molecules.
All of the above are correct.
None of the above is correct.
*d. All of the above are correct.
2.
a.
b.
c.
d.
e.
The average air pressure at sea level is
14.7 lb per square inch.
1013.25 mb.
101,325 Pascals.
All of these are correct.
None of these is correct.
*d. All of these are correct.
3.
a.
b.
c.
d.
e.
The usual world-wide range in sea-level air pressure is ______ mb.
less than 20
less than 2
less than 100
more than 100
more than 1000
*c. less than 100
4.
a.
b.
c.
d.
e.
The type of barometer that is used to measure altitude:
mercury
aneroid
thermal
radiosonde
psychrometer
*b. aneroid
5. A barometer can be used to predict the weather by
a. reading the legends on the face of the barometer.
b. keeping track of the air pressure tendency.
c. using the instrument as an altimeter.
d. None of the above is correct.
*b. keeping track of the air pressure tendency.
6. An air-pressure altimeter is actually a(n) ______ barometer.
a. mercury
b. aneroid
*b. aneroid
7.
a.
b.
c.
d.
e.
The top of the atmosphere is at an average altitude of
80 km.
100 km.
5 km.
10 km.
None of these is correct.
*e. None of these is correct.
8.
a.
b.
c.
d.
e.
The pressure of the atmosphere is greatest
at the tropopause.
at the Earth's surface.
at sea level.
at the mesopause.
at the stratopause.
*c. at sea level.
9.
a.
b.
c.
Between the tropopause and stratopause, the air pressure ______ with increasing altitude.
increases
decreases
does not change
*b. decreases
10. What fraction of the atmosphere's mass is below an aircraft flying at the 400 mb level?
a. 0.6
b. 0.4
c. 0.2
d. 0.3
e. 0.1
*a. 0.6
11. What fraction of the atmosphere is below the 500 mb level?
a. 0.6
b. 0.8
c. 0.5
d. 0.3
e. 0.2.
*c. 0.5
12. Within the thermosphere, the temperature is ______ and heat energy is ______.
a. low..............low
b. high..............high
c. low...............high
d. high..............low
*d. high..............low
13. When air pressure readings at Denver (the "mile-high city") are adjusted to sea level, air
pressure readings are
a. increased.
b. decreased.
c. not changed.
*a. increased.
14. Adjusting barometer readings to sea-level removes the influence of ______ on air pressure.
a. air temperature
b. wind speed
c. station elevation
d. humidity
e. divergence
*c. station elevation
15. An air mass is a huge volume of air that is relatively uniform horizontally in
a. temperature.
b. humidity.
c. Both of these are correct.
d. None of these is correct.
*c. Both of these are correct.
16. At the same pressure, warm, dry air is ______ cold, dry air.
a. denser than
b. less dense than
c. about as dense as
*b. less dense than
17. At the same pressure, warm and humid air is ______ equally warm and dry air.
a. denser than
b. less dense than
c. about as dense as
*b. less dense than
18. At the same temperature and pressure, humid air is ______ dry air.
a. denser than
b. less dense than
c. about as dense as
*b. less dense than
19. With the same volumes, a cold and dry air mass exerts ______ surface air pressure than a
warm and humid air mass.
a. higher
b. lower
*a. higher
20. With the same volumes, a warm and dry air mass exerts ______ surface air pressure than an
equally warm but humid air mass.
a. higher
b. lower
*a. higher
21. When a warm and humid air mass replaces a cold and humid air mass at a particular locality,
the air pressure at Earth’s surface usually
a. rises.
b. falls.
c. does not change.
* b. falls.
22. Relatively high surface air pressure is usually accompanied by ______ weather whereas
relatively low surface air pressure is usually accompanied by ______ weather.
a. fair..............stormy
b. stormy..............fair
*a. fair..............stormy
23. The decline of air pressure with altitude is most rapid in ______ air masses.
a. warm and humid
b. cold and humid
c. warm and dry
d. cold and dry
*d. cold and dry
24. The troposphere is denser in ______ than in ______
a. winter...............summer
b. summer..............winter
*a. winter...............summer
25. The tropopause is lower in ______ than in ______.
a. winter..............summer
b. summer..............winter
*a. winter..............summer
26. If the surface air pressure is the same everywhere, but a mass of cold air is situated next to a
mass of warm air, the pressure at high altitudes is
a. greater in the warm air.
b. greater in the cold air.
c. greater between the warm air and cold air.
d. the same in the warm air and the cold air.
*a. greater in the warm air.
27. Changes in air pressure with time at a particular locality may be explained by
a. local radiational heating or cooling.
b. air mass advection.
c. divergence or convergence of surface winds.
d. All of the above are correct.
*d. All of the above are correct.
28. With cold air advection in winter, the air pressure tendency is usually
a. upward
b. downward
c. unchanged
*a. upward
29. With warm air advection in winter, the air pressure tendency is usually _____.
a. upward
b. downward
c. unchanged
*b. downward
30. A variable of state in the atmosphere:
a. temperature
b. pressure
c. density
d. All of these are correct.
e. None of these is correct.
*d. All of these are correct.
31. Within the atmosphere,
a. air temperature always decreases with altitude.
b. air density always increases with altitude.
c. air pressure always decreases with altitude.
d. All of these are correct.
e. None of these is correct.
*c. air pressure always decreases with altitude.
32. According to the gas law, air pressure is directly proportional to
a. air density.
b. air temperature.
c. Both of these are correct.
d. None of these is correct.
*c. Both of these are correct.
33. As a mass of arctic air invades our locality, air temperature ______ and air density ______.
a. falls...............increases
b. rises..............increases
c. falls...............decreases
d. rises...............decreases
*a. falls...............increases
34. As a mass of warmer and more humid air invades our locality, air temperature _____ and air
density _____.
a. falls..............increases
b. rises...............increases
c. falls...............decreases
d. rises...............decreases
*d. rises...............decreases
35. Usually, the air pressure inside a building is _____ the air pressure outside the building.
a. greater than
b. about the same as
c. less than
*b. about the same as
36. In order that barometer readings are accurate and representative,
a. the instrument must always be mounted outdoors and in a special instrument shelter.
b. the instrument must always be mounted outdoors but not in a special instrument
c. the instrument must always face the sun during daylight hours.
d. the instrument may be mounted indoors.
e. None of the above is correct.
shelter.
*d. the instrument may be mounted indoors.
37. The standard atmosphere
a. is a model of the real atmosphere.
b. features a mean sea-level air pressure of 1013.25 mb.
c. may be useful in reducing barometer readings to sea level.
d. All of the above are correct.
e. None of the above is correct.
*d. All of the above are correct.
38. The elevation of the 500-mb surface
a. depends on the average temperature of the air between Earth's surface and the 500-mb level.
b. varies with latitude and time.
c. can be determined by a radiosonde.
d. All of the above are correct.
e. None of the above is correct.
*d. All of the above are correct.
39. Air pressure decreases ______ with increasing altitude.
a. uniform
b. nonuniformly
*b. nonuniformly
40. The concentration of oxygen (O2) in parts per million ______ with increasing altitude
within the troposphere.
a. decreases
b. increases
c. does not change
*a. decreases
41. Differences in the altitude of the 500-mb surface from one place to another can be explained
primarily by differences in __________ of the air below the 500-mb surface.
a. humidity
b. temperature
c. wind speed
d. None of the above is correct
*b. temperature
42. Two weather stations (A and B) at sea level report the same surface air pressures. Warm air
is above Station A while relatively cold air is above Station B. At an altitude of 25,000 feet, one
would expect the pressure above Station A to be
a. higher than that above Station B.
b. lower than that above Station B.
c. the same as that above Station B.
*a. higher than that above Station B.
43. Highs and Lows are identified on surface weather maps by areas enclosed within isobars.
Which one of the following statements about Highs is true?
a. The highest pressure in a High must always be higher than the lowest pressure in a Low on
the same weather map.
b. Air pressure increases outward from the center of a High.
c. All Highs must have central pressures with values greater than 1013.25 mb.
d. There must be one and only one High for each Low on the same weather map.
*a. The highest pressure in a High must always be higher than the lowest pressure in a Low on
the same weather map.
44. Lows and Highs are identified on surface weather maps by areas enclosed within isobars.
Which one of the following statements about Lows is true?
a. The lowest pressure in a Low must always be lower than the highest pressure in a High on the
same weather map.
b. Air pressure decreases outward from the center of a Low.
c. All Lows must have central pressures with values less than 1013.25 mb.
d. There must be one and only one Low for each High on the same weather map.
*a. The lowest pressure in a Low must always be lower than the highest pressure in a High on
the same weather map.
45. Normal atmospheric pressure may be expressed in all of the following ways except
a. 30 inches of mercury
b. 76 cm of mercury
c. 1013 millibars
d. 62.4 lbs per square foot.
*d. 62.4 lbs per square foot.
46. A typical sea-level pressure could be
a. 760 cm of mercury.
b. 1100 mb.
c. 30 inches of mercury.
d. Any of the above is correct.
*c. 30 inches of mercury.
47. Compared to horizontal pressure gradients, vertical pressure gradients are
a. much greater.
b. about the same.
c. much smaller.
*a. much greater.
48. Changes of air pressure in the horizontal are
a. much larger than they are in the vertical.
b. about the same as they are in the vertical.
c. much smaller than they are in the vertical.
*c. much smaller than they are in the vertical.
49. Half of the Earth's atmosphere (by weight) is located within approximately
a. 3.5 miles of sea level.
b. 29.92 miles of sea level
c. 100 miles of sea level.
d. one mile of sea level.
*a. 3.5 miles of sea level.
50. At an altitude of about 3.5 miles above sea level, the air pressure is approximately
a. 1000 mb.
b. 750 mb.
c. 500 mb.
d. 250 mb.
*c. 500 mb.