Astronomy Ch 9

10. The nitrogen in Earth's atmosphere primarily came from a. ammonia delivered by comet impacts. b. photosynthesis done by algae and plants. c. oxidation of silicate-rich minerals. d. rock delivered by asteroid impacts. e. its primary atmosphere.

A

16. The terrestrial planets, ranked in order of decreasing atmospheric density, are a. Venus, Earth, Mars, Mercury b. Venus, Mars, Earth, Mercury c. Mercury, Mars, Earth, Venus d. Mars, Venus, Mercury, Earth

A

18. Earth releases the energy it receives from the Sun by emitting _________ radiation. a. infrared b. visible c. ultraviolet (UV) d. radio e. microwave

A

22. The greenhouse effect is the a. trapping of infrared radiation by the atmosphere. b. accentuated growth of plants near the equator, compared to other regions. c. capturing of visible and UV radiation from the Sun the atmosphere. d. shielding of life-forms from solar UV radiation by the ozone layer.

A

42. Without the ozone layer, life on Earth would be in danger from increased levels of _________ radiation. a. UV b. X-ray c. gamma ray d. infrared e. microwave

A

61. The absence of oxygen on Mars means that it has very little a. carbon dioxide. b. methane. c. ozone. d. helium.

C

34. _________ in our atmosphere is a direct consequence of the emergence of life. a. Carbon dioxide b. Water vapor c. Nitrogen d. Oxygen e. Helium

D

50. Heating from _________ causes the top of Earth's stratosphere to be warmer than the bottom. a. higher-energy particles in the solar wind b. convection c. the ozone layer absorbing UV light d. charged particles trapped by magnetic fields e. the greenhouse effect

C

44. The planet-wide flow of air from Earth's equator to the colder poles is called Hadley circulation. An example of this effect is also seen a. on Mars b. on Mercury c. on Venus d. nowhere else in the solar system

C

47. According to the following figure, as you increase in altitude in Earth's lower atmosphere, the atmospheric pressure ________ dramatically at a(n) _________ rate. a. increases; increasing b. increases; decreasing c. decreases; decreasing d. decreases; increasing e. decreases; constant

C

21. The greenhouse effect raises Earth's surface temperature by roughly a. 0 K. b. 0.35 K. c. 3.5 K. d. 35 K. e. 350 K.

D

60. Venus rotates so rapidly that the dominant form of atmospheric circulation is powered by a. winds moving from its equator to its poles. b. heated air escaping from its volcanoes moving along the equator. c. winds moving from its poles to its equator. d. heated air escaping from active tectonic plates.

A

1. The major chemical component of the air we breathe today was deposited on Earth primarily via a. volcanic eruptions. b. cometary impacts. c. asteroid impacts. d. chemical reactions in Earth's oceans.

B

13. Earth has roughly _________ times more atmospheric pressure than Mars and _________ times less than Venus. a. 10; 10 b. 200; 100 c. 2,000; 2 d. 2; 10 e. 1,000; 200

B

33. The best way to use a telescope to look for life on other planets is to a. search for absorption from nitrogen in their atmospheres. b. search for absorption from oxygen in their atmospheres. c. search for emission lines from water vapor in their atmospheres. d. search for carbon dioxide on their moons.

B

36. By approximately _________ years ago, _________ had produced oxygen in enough amounts to be a significant fraction in Earth's atmosphere. a. 100 million; trees and plants b. 1 billion; trees and plants c. 250 million; bacteria and algae d. 2.5 billion; bacteria and algae e. 2,000; animals and humans

C

40. According to the figure below, approximately how many years ago did oxygen finally get to half its current abundance in Earth's atmosphere? a. 3 billion years ago b. 1 billion years ago c. 0.6 billion years ago d. 0.25 billion years ago e. 0.1 billion years ago

C

62. When the Martian springtime arrives and the daytime temperature reaches 20°C, what occurs? a. Water melts and forms large pools of liquid. b. The polar ice caps disappear. c. Large planet-wide dust storms. d. The entire planet changes color.

C

9. Which of the following processes did not contribute gas to Earth's secondary atmosphere? a. volcanism b. accretion c. oxidation d. comet impacts e. All of the above contributed gases to Earth's secondary atmosphere.

C

14. If the carbon dioxide in Earth's rocks were suddenly released into its atmosphere, what would happen? a. It would rapidly escape into space. b. It would dissociate into carbon and oxygen. c. It would collect as ice on the north and south poles. d. It would cause a runaway greenhouse effect.

D

39. Why are auroras produced only near the northern and southern magnetic poles of a planet? a. Those are the locations where the atmosphere is thinner, letting particles penetrate. b. The poles are pointing toward the Sun, so they receive more solar wind particles. c. The oxygen atoms responsible for auroral emission only exist near the poles. d. Charged particles are forced to flow along Earth's magnetic field lines, which come out of Earth's poles.

D

69. When frozen water on the surface of Mars heats up during summer time, the water a. melts and forms liquid pools on the surface. b. boils off the surface and escapes into outer space. c. sublimates and goes directly into the gaseous phase. d. remains frozen because the temperature remains below the freezing point. e. melts and creates flowing rivers that erode the landscape.

C

3. Why did the terrestrial planets lose the majority of the gas in their primary atmospheres? a. They were too hot and their escape velocities too low to hold onto them. b. The solar wind was too strong and blew these gases off the planets. c. Their high surface temperatures made the gas chemically react with the rock. d. The initial gases were so heavy when the planet differentiated that they sank to the core.

A

30. The major difference in the composition of Earth's atmosphere compared to the atmospheres of Venus and Mars is a direct consequence of a. life on Earth. b. Earth's plate tectonics. c. differences in the greenhouse effect. d. the presence of liquid water. e. differing distances from the Sun.

A

37. Approximately how long after the Solar System formed did it take for oxygen to get to within 80 percent of its present abundance in Earth's atmosphere? a. 4 billion years b. 1 billion years c. 400 million years d. 1 million years e. Oxygen was always a primary component of Earth's atmosphere.

A

38. For the first 1 billion years of Earth's evolution, the fraction of oxygen in its atmosphere was approximately a. zero. b. half of what it is today. c. 2 times what it is today. d. 10 times what it is today. e. the same as it is today.

A

43. According to the following figure, the different layers of Earth's atmosphere are defined by a. how the temperature varies with altitude. b. how the pressure varies with altitude. c. how the density varies with altitude. d. different temperature ranges. e. different pressure ranges.

A

46. All weather and wind on Earth are a result of convection in the a. troposphere. b. stratosphere. c. mesosphere. d. ionosphere. e. thermosphere.

A

5. Would water molecules in Venus's atmosphere, whose temperature is 740 K, eventually es-cape into outer space? Note that a water molecule has a mass that is 18 times that of a hy-drogen atom. The escape velocity of Venus is 10 km/s. For comparison, a hydrogen atom has an average velocity of 2.5 km/s at a temperature of 300 K. a. No, the average velocity of water molecules is 0.9 km/s. b. Yes, the average velocity of water molecules is 0.9 km/s. c. Yes, the average velocity of water molecules is 2.1 km/s. d. No, the average velocity of water molecules is 2.1 km/s. e. Yes, the average velocity of water molecules is 19 km/s.

A

52. Auroras are caused by a. gases fluorescing in the atmosphere because of collisions with solar wind particles. b. the magnetosphere of Earth touching its atmosphere. c. the ozone layer being destroyed by UV light. d. a product of the atmospheric greenhouse effect. e. scattering of sunlight from particles in Earth's stratosphere.

A

57. Given the thickness and chemical composition of Venus's atmosphere, by how much would you expect its average surface temperature to change between day and night? a. There should be almost no change in temperature. b. by tens of K (like Earth) c. by hundreds of K (like Mercury) d. The answer depends on where Venus is in its orbit around the Sun.

A

58. Earth's sky is blue because a. blue light from the sun is more readily scattered by molecules in the atmosphere than red light. b. of reflected light from the oceans. c. red light from the sun is more readily scattered by molecules in the atmosphere than blue light. d. molecules that make up Earth's atmosphere radiate preferentially at blue wavelengths. e. the Sun radiates more blue light than other wavelengths.

A

15. The presence of gases such as carbon dioxide and water vapor in a planet's atmosphere is direct evidence of _________ in a planet's history. a. high surface temperatures b. volcanic activity c. cometary impacts d. a lack of asteroid impacts e. the greenhouse effect

B

19. In the absence of a greenhouse effect, what would happen to Earth's oceans? a. They would evaporate. b. They would freeze over. c. They would be rapidly absorbed into the surface rocks. d. They would dissociate into ozone and hydrogen.

B

2. How does the fraction of oxygen in Earth's atmosphere today compare to what it was 3 billion years ago? a. It has significantly declined. b. It has significantly increased. c. It kept increasing up to 2 billion years ago but has been declining ever since. d. It hasn't changed.

B

29. Venus and Earth probably formed with similar amounts of carbon dioxide in their secondary atmospheres. Which of the following is true? a. The majority of Earth's carbon dioxide escaped into space because of its hotter temperature, whereas Venus's carbon dioxide remains gravitationally bound to Venus. b. The majority of Earth's carbon is now bound up in rock, whereas Venus's remains in its atmosphere. c. Earth lost more of its secondary atmosphere because it was bombarded by more planetesimals than Venus. d. The majority of Earth's carbon was absorbed by plants during photosynthesis. e. Earth and Venus still have equal amounts of carbon dioxide in their atmospheres.

B

35. If photosynthesis were to disappear on Earth, a. the atmosphere would become less dense. b. oxygen would disappear from the atmosphere. c. the atmosphere would become hotter. d. nitrogen would disappear from the atmosphere. e. the amount of water vapor in the atmosphere would decrease.

B

4. Would a nitrogen atom in Venus's atmosphere, whose temperature is 740 K, eventually es-cape into outer space? Note that a nitrogen atom has a mass that is 14 times that of a hydro-gen atom. Recall that atoms eventually will escape if their average velocity is greater than 1/6 times the escape velocity of the planet. The escape velocity of Venus is 10 km/s. For comparison, a hydrogen atom has an average velocity of 2.5 km/s at a temperature of 300 K. a. The average velocity of nitrogen atoms is 0.4 km/s, and nitrogen does not escape. b. The average velocity of nitrogen atoms is 1.0 km/s, and nitrogen does not escape. c. The average velocity of nitrogen atoms is 1.0 km/s, and nitrogen escapes. d. The average velocity of nitrogen atoms is 4.5 km/s, and nitrogen does not escape. e. The average velocity of nitrogen atoms is 4.5 km/s, and nitrogen escapes.

B

45. According to the way the layers of Earth's atmosphere are defined in the following figures, the atmosphere of Venus has only _________ distinct layer(s). a. one b. two c. three d. four e. five

B

49. Winds are generated on Earth primarily because of a. strong updrafts from the equator and air sinking near the poles. b. uneven heating of the surface and rotation of the planet. c. water condensation onto mountains. d. hot air rising and cool air sinking.

B

51. The shape of Earth's magnetosphere is modified by a. the Moon's tidal force. b. the solar wind. c. Earth's own gravity. d. asymmetries in the shape of Earth's core. e. Earth's elliptical orbit.

B

53. In the Southern Hemisphere, hurricanes _________ compared to hurricanes in the Northern Hemisphere because of the Coriolis effect. a. rotate in the same direction b. rotate in the opposite direction c. move from east to west d. have larger wind speeds e. cause more damage

B

59. Which of the following is not a consequence of the high thickness and peculiar composition of Venus's atmosphere? a. We cannot see down to its surface in visible light. b. Its surface is very smooth. c. Venus looks highly reflective. d. The surface pressure is 100 times higher than on Earth's surface.

B

64. Venus has an unusual rotation rate because a. it is very slow. b. it is very slow and retrograde. c. its obliquity is 90 degrees. d. it is very fast. e. it is very fast and retrograde.

B

8. A gas eventually will escape from a planet's atmosphere if the average velocity of the atoms exceeds 1/6 times the escape velocity of the planet. If the average velocity of water vapor in Venus's atmosphere is 0.9 km/s, would it eventually escape into outer space? Note that Venus's mass is 5 × 1024 kg, and its radius is 6,050 km. a. Water vapor would escape because 1/6 times the escape velocity is 0.51 km/s. b. Water vapor would not escape because 1/6 times the escape velocity is 1.7 km/s. c. Water vapor would escape because 1/6 times the escape velocity is 0.42 km/s. d. Water vapor would not escape because 1/6 times the escape velocity is 2.6 km/s. e. Water vapor would escape because 1/6 times the escape velocity is 1.3 km/s.

B

11. Based solely on mass and distance from the Sun, which of the following terrestrial planets would you expect to retain the densest secondary atmosphere? a. Mercury b. Venus c. Mars d. the Moon e. Earth

C

17. The main greenhouse gases in the atmosphere of the terrestrial planets are a. oxygen and nitrogen. b. methane and ozone. c. carbon dioxide and water vapor. d. hydrogen and helium. e. methane and ammonia.

C

20. What makes carbon dioxide a highly effective greenhouse gas? a. It easily absorbs UV radiation. b. It easily absorbs visible light. c. It easily absorbs infrared radiation. d. It easily reacts chemically with rock. e. It easily photodissociates in the upper atmosphere.

C

28. Like Mars and Venus, Earth originally had a significant amount of carbon dioxide in its atmosphere. Where is the majority of the carbon now? a. It has escaped into outer space. b. It is bound up in the plant life on Earth. c. It is bound up in rocks. d. It is dissolved into the oceans. e. It is still in the atmosphere in the form of complex molecules.

C

56. Hurricanes are powered by a. Hadley circulation. b. the Coriolis effect. c. the heat of vaporization of water. d. electrical conductivity of water. e. the greenhouse effect.

C

6. If sunlight broke up water molecules in Venus's atmosphere, would the hydrogen atoms es-cape into outer space? Note that Venus's temperature is 740 K. Recall that gas eventually will escape if the average velocity of its atoms is greater than 1/6 times the escape velocity of the planet. The escape velocity of Venus is 10 km/s. a. No, the average velocity of hydrogen atoms would be 0.8 km/s. b. No, the average velocity of hydrogen atoms would be 3.9 km/s. c. Yes, the average velocity of hydrogen atoms would be 3.9 km/s. d. Yes, the average velocity of hydrogen atoms would be 25 km/s. e. No, the average velocity of hydrogen atoms would be 25 km/s.

C

66. Each halogen atom, such as chlorine, fluorine, and bromine, in Earth's atmosphere contributes to a. the production of carbon dioxide. b. the production of acid rain. c. the destruction of ozone over decades and centuries. d. the destruction of water in the upper atmosphere.

C

68. The amount of carbon dioxide in Earth's atmosphere has been increasing over the last 50 years because of a. global warming. b. the growth of the ozone hole. c. the burning of fossil fuels. d. increased energy output from the Sun. e. increased magnetic activity in the Sun.

C

24. If water vapor were released from Venus's surface because of tectonic activity into its upper atmosphere, what would most likely happen to it? a. The water vapor would relieve the greenhouse effect and decrease Venus's surface temperature. b. Water droplets would condense into rain and form lakes on Venus's surface. c. The water vapor would chemically react with carbon dioxide and form acid rain. d. UV light would break apart the water molecules, and the hydrogen would be lost into space. e. It would rise into the atmosphere and form hurricane-like storms.

D

25. When learning about light, we predicted that Venus should have a temperature of 250 K based on its albedo and distance from the Sun. Why is Venus's observed average surface temperature equal to 740 K, which is hot enough to melt lead? a. Venus has slow, retrograde rotation, and its seasons are very long. b. Venus has many active volcanoes that release heat into its atmosphere. c. Venus has a very thin atmosphere, and more sunlight falls onto its surface. d. Venus has a strong greenhouse effect. e. Venus has a highly eccentric orbit and is sometimes much closer to the Sun than other times.

D

26. In the absence of the greenhouse effect, the water on the surface of Earth would a. escape into outer space. b. remain in liquid form. c. vaporize and form clouds in the atmosphere. d. freeze. e. be absorbed into rocks.

D

31. According to the following figure, about how long ago did oxygen reach its current abundance in Earth's atmosphere? a. 3 billion years ago b. 1 billion years ago c. 0.5 billion years ago d. 0.25 billion years ago e. 0.1 billion years ago

D

41. If you found absorption from _________ in the spectrum of a planet, you could conclude that it might contain some form of life. a. oxygen b. methane c. water vapor d. oxygen, methane, or water vapor

D

48. The only two layers of Earth's atmosphere that have temperature gradients that allow convection to take place are a. the troposphere and the thermosphere. b. the mesosphere and the stratosphere. c. the thermosphere and the stratosphere. d. the troposphere and the mesosphere. e. the troposphere and the stratosphere.

D

54. What is the main reason Hadley circulation in a planet's atmosphere breaks up into zonal winds? a. convection driven by solar heating b. heating from the solar wind c. hurricanes developing along the planet's equator d. a planet's rapid rotation e. heating from the greenhouse effect

D

63. The exospheres of the Moon and Mercury differ from the atmospheres of Venus, Earth and Mars in that a. they are made of a very thin layer of carbon dioxide. b. they are made of a thick layer of water vapor. c. they extend much farther from the rocky surface. d. they are made of a thin layer of light atoms such as helium, sodium, and argon.

D

65. Venus's surface temperature is fairly uniform from the equator to the poles because a. Venus rotates very rapidly, which causes strong zonal winds. b. Venus is covered by a thick cloud layer that absorbs most of the sunlight that falls on it. c. the carbon dioxide in Venus's atmosphere efficiently emits infrared radiation. d. Venus rotates slowly so Coriolis forces do not disrupt Hadley circulation. e. Venus's orbit is nearly perfectly circular.

D

7. If an average hydrogen atom in Earth's atmosphere has a velocity of 2.5 km/s, what would be the average velocity of an oxygen molecule in Earth's atmosphere? Note that the atomic mass of an oxygen atom is 16 times that of a hydrogen atom. a. 0.16 km/s b. 2.5 km/s c. 0.62 km/s d. 0.44 km/s e. 0.25 km/s

D

70. Global temperature variations on Earth driven by the Milankovitch cycle differ from those driven by the anthropogenic greenhouse effect in that a. they are very small in magnitude, less than 1°C. b. they occur at irregular time intervals. c. they are driven by volcanic activity. d. they occur over much longer time scales (thousands of years). e. they are driven by emissions of methane gas rather than carbon dioxide.

D

12. Which molecule moves with the fastest average speed while being bound in Earth's atmosphere in thermal equilibrium? a. Water, H2O (atomic mass = 18) b. Carbon dioxide, CO2 (atomic mass = 44) c. Nitrogen (atomic mass = 28) d. Oxygen (atomic mass = 32) e. Hydrogen, H2 (atomic mass = 2)

E

2. What is the reason Mercury has so little gas in its atmosphere? a. Its mass is small. b. It has a high temperature. c. It is close to the Sun. d. Its escape velocity is low. e. all of the above

E

23. If it were not for the greenhouse effect on Earth, a. there would be no liquid water on Earth. b. life as we know it would not have developed on Earth. c. it would be a much colder planet. d. there would be no oxygen in Earth's atmosphere. e. All of the above are results of the greenhouse effect.

E

27. By examining the following three images, what can you conclude? a. Venus is covered with clouds. b. Earth has a large amount of liquid water. c. Some form of ice does exist on Mars, but it does not have large amounts of liquid water. d. The planets in order from the least to most dense atmospheres are Venus, Earth, and Mars. e. all of the above

E

55. Runaway convection in Earth's atmosphere can lead to a. snow. b. destruction of ozone. c. auroras. d. acid rain. e. violent storms.

E

67. Humans cannot survive on the surface of Mars for long periods of time because a. there is not enough oxygen in the atmosphere. b. the range in temperature between day and night is too large. c. the flux of UV radiation reaching the surface is too high. d. the atmospheric pressure would be too low. e. all of the above

E