CHAPTER 5

 

Air Pressure

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MULTIPLE CHOICE QUESTIONS

 

1. The magnitude of pressure exerted by the gas molecules composing air depends on

a. the mass of the air molecules.

b. the pull of gravity.

c. the kinetic energy of air molecules.

d. All of the above are correct.

e. None of the above is correct.

 

2. 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

 

3. So 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 shelter.

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.

 

4. The average air pressure at sea level is

a. 14.7 lb per square inch.

b. 1013.25 mb.

c. 101,325 Pascals.

d. All of these are correct.

e. None of these is correct.

 

5. The usual world-wide range in sea-level air pressure is ______ mb.

a. less than 20

b. less than 2

c. less than 100

d. more than 100

e. more than 1000

 

6. Between the tropopause and stratopause, the air pressure ______ with increasing altitude.

a. increases

b. decreases

c. does not change

 

7. The top of the atmosphere is at an average altitude of __________ km.

a. 80.

b. 100.

c. 5.

d. 10.

e. None of these is correct.

 

8. 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

 

9. 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.

 

10. 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.

 

11. 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.

 

12. At an altitude of about 3.5 mi above sea level, the air pressure is approximately

a. 1000 mb.

b. 750 mb.

c. 500 mb.

d. 250 mb.

 

13. The pressure of the atmosphere is greatest

a. at the tropopause.

b. at the Earth's surface.

c. at sea level.

d. at the mesopause.

e. at the stratopause.

 

14. The type of barometer that is used to measure altitude:

a. mercury

b. aneroid

c. thermal

d. radiosonde

e. psychrometer

 

15. 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.

 

16. An air-pressure altimeter is actually a(n) ______ barometer.

a. mercury

b. aneroid

 

17. Within the thermosphere, the temperature is ______ and heat energy is ______.

a. low..............low

b. high..............high

c. low...............high

d. high..............low

 

18. When air pressure readings at Denver (the "mile-high city") are adjusted to sea level, barometric pressure readings are

a. increased.

b. decreased.

c. not changed.

 

19. 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

 

20. 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.

 

21. 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.

 

22. Air pressure decreases ______ with increasing altitude.

a. uniform

b. non-uniformly

 

23. The concentration of oxygen (O2) in parts per million by volume ______ with increasing altitude within the troposphere.

a. decreases

b. increases

c. does not change

 

24. The temperature of rising parcels of unsaturated air __________ because of __________.

a. drops. . . . . . .compressional warming

b. drops. . . . . .expansional cooling

c. drops. . . . . . .radiational cooling

d. drops. . . . . . .latent heating

e. rises. . . . . . . .compressional warming

 

25. At the same pressure, warm, dry air is ______ cold, dry air.

a. denser than

b. less dense than

c. about as dense as

 

26. 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

 

27. At the same temperature and pressure, humid air is ______ dry air.

a. denser than

b. less dense than

c. about as dense as

 

28. 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

 

29. The tropopause is lower in ______ than in ______.

a. winter..............summer

b. summer..............winter

 

30. 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.

 

31. 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

 

32. 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

 

33. When a warm and humid air mass replaces a cold and dry air mass at a particular locality, the air pressure at Earth’s surface usually

a. rises.

b. falls.

c. does not change.

 

34. 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

 

35. Because of the usual seasonal change in average temperature, the troposphere is denser in __________ than in __________.

a. winter...............summer

b. summer..............winter

 

36. Compared to horizontal pressure gradients, vertical pressure gradients are

a. much greater.

b. about the same.

c. much smaller.

 

37. 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.

 

38. With cold air advection in winter, the air pressure tendency is usually

a. upward

b. downward

c. unchanged

 

39. With warm air advection in winter, the air pressure tendency is usually _____.

a. upward

b. downward

c. unchanged

 

40. 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.

 

41. 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. Air pressure decreases outward from the center of a High.

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.

 

42. 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. Air pressure increases outward from the center of a Low.

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.

 

43. 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.

 

44. 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.

 

45. 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.

 

46. 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

 

47. 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

 

48. Rising parcels of unsaturated air cool at a _________ rate than rising parcels of saturated (cloudy) air.

a. slower

b. faster

 

49. The dry adiabatic lapse rate is __________ Celsius degrees per 1000 m.

a. 6.0

b. 2.9

c. 9.8

d. 12.8

 

50. Descending air warms at

a. the dry adiabatic lapse rate.

b. the rate of 9.8 Celsius degrees per 1000 m.

c. the rate of 5.5 Fahrenheit degrees per 1000 ft.

d. All of the above are correct.

e. None of the above is correct.