DONE-ASTR 263-practice-final-2008 PDF

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December 2, 2008

Purdue University Astronomy 263 Practice Final Prof. Ian Shipsey The final will consist of eighty questions. About half will cover material since Midterm II, about one quarter will cover material from Midterm I, and one quarter will cover material from Midterm II. The questions below are only on material since Midterm II. Please choose the best answer to the following questions. You are not penalized for guessing you will therefore maximize your score by attempting all questions. This is a closed book exam. No teaching aids are allowed, no notes, crib sheets, textbooks, calculators, cell phones, pagers , PDA''s or laptops. These items should be turned off and put away for the duration of the exam. Please remember to enter your name and Purdue ID number and to sign your opscan sheet. Leave the area marked ".Section". blank. When you have finished the exam, please hand in your opscan sheet, you may then leave. Please do so quietly so as not to disturb others. Thanks, and good luck! Questions 1- 11 are from ch. 8 Questions 12- 32 are from ch. 9 Questions 33- 49 are from ch. 10 Questions 50- 69 are from ch. 11 Questions 70- 88 are from ch. 12 Questions 89- 96 are from ch. 13

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

1) Where did the elements heavier than hydrogen and helium come from? A) They evolved from hydrogen and helium shortly after the Big Bang. B) They were produced inside dense interstellar gas. C) They were produced in the Big Bang. D) They were produced inside stars. E) all of the above 2) Why did the solar nebula heat up as it collapsed? A) Nuclear fusion occurring in the core of the protosun produced energy that heated the nebula. B) As the cloud shrank, its gravitational potential energy was converted to kinetic energy and then into thermal energy. C) Collisions among planetesimals generated friction and heat. D) The shock wave from a nearby supernova heated the gas. E) Radiation from other nearby stars that had formed earlier heated the nebula. 3) Why did the solar nebula flatten into a disk? A) It flattened as a natural consequence of collisions between particles in the nebula, changing random motions into more orderly ones. B) The interstellar cloud from which the solar nebula formed was originally somewhat flat. C) As the nebula cooled, the gas and dust settled onto a disk. D) The force of gravity pulled the material downward into a flat disk.

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4) According to our theory of solar system formation, why do all the planets orbit the Sun in the same direction and in nearly the same plane? A) The Sun formed first, and as it grew in size it spread into a disk, rather like the way a ball of dough can be flattened into a pizza by spinning it. B) The laws of conservation of energy and conservation of angular momentum ensure that any rotating, collapsing cloud will end up as a spinning disk. C) The original solar nebula happened to be disk- shaped by chance. D) Luck explains it, as we would expect that most other solar systems would not have all their planets orbiting in such a pattern. E) Any planets that once orbited in the opposite direction or a different plane were ejected from the solar system. 5) What was the frost line of the solar system? A) the distance from the Sun where temperatures were low enough for hydrogen and helium to condense, between the present- day orbits of Jupiter and Saturn B) the distance from the Sun where temperatures were low enough for asteroids to form, between the present- day orbits of Venus and Earth C) the distance from the Sun where temperatures were low enough for rocks to condense, between the present- day orbits of Mercury and Venus D) the distance from the Sun where temperatures were low enough for hydrogen compounds to condense into ices, between the present- day orbits of Mars and Jupiter E) the distance from the Sun where temperatures were low enough for metals to condense, between the Sun and the present- day orbit of Mercury 6) Which of the following is the origin of almost all the large moons around the jovian planets? A) They were formed by condensation and accretion in a disk of gas around the planet. B) They are captured asteroids. C) They are captured comets. D) They are captured planets. E) They were formed by giant impacts. 7) Observations of young stars (as well as theory) tell us that when the Sun was young the solar wind A) blew outward only along the Sun's poles. B) was stronger than it is today. C) was weaker than it is today. D) was nonexistent. E) was about the same strength as it is today.

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8) Which of the following are relatively unchanged fragments from the early period of planet building in the sola system? A) asteroids B) Kuiper belt comets C) Oort cloud comets D) meteorites E) all of the above 9) According to the nebular theory, how did the Oort cloud form? A) It is material left over from the interstellar cloud that never contracted with the rest of the gases to form the solar nebula. B) It is made of planetesimals that formed beyond Neptune's orbit and never accreted to form a planet. C) It is made of planetesimals formed in the outer solar system that were flung into distant orbits by encounters with the jovian planets. D) It consists of objects that fragmented from the protosun during a catastrophic collision early in the formation of the solar system. E) It is made of planetesimals between the orbits of Mars and Jupiter that never formed into a planet. 10) The nebular theory of the formation of the solar system successfully predicts all but one of the following. Which one does the theory not predict? A) the equal number of terrestrial and jovian planets (with the exception of Pluto) B) Planets orbit around the Sun in nearly circular orbits in a flattened disk. C) the craters on the Moon D) asteroids, Kuiper- belt comets, and the Oort cloud E) the compositional differences between the terrestrial and jovian planets 11) The age of the solar system can be established by radioactive dating of A) the oldest rocks on the earth. B) the oldest meteorites. C) the atmosphere of Mars. D) the oldest rocks on the Moon. E) It hasn't been done yet, but the age of the solar system could be obtained from a sample of Io's surface. 12) Rank the five terrestrial worlds in order of size from smallest to largest: A) Mercury, Venus, Earth, Moon, Mars. B) Mercury, Moon, Mars, Earth, Venus. C) Mercury, Moon, Venus, Earth, Mars. D) Moon, Mercury, Venus, Earth, Mars. E) Moon, Mercury, Mars, Venus, Earth. 3

13) What is differentiation in planetary geology? A) any process by which a planet's surface evolves differently from another planet's surface B) any process by which a planet evolves differently from its moons C) any process by which one part of a planet's surface evolves differently from another part of the same planet's surface D) the process by which different types of minerals form a conglomerate rock E) the process by which gravity separates materials according to density 14) Under what circumstances can differentiation occur in a planet? A) The planet must be geologically active, that is, have volcanoes, planetquakes, and erosion from weather. B) The planet must be made of both metal and rock. C) The planet must have a rocky surface. D) The planet must have a molten interior. E) The planet must have an atmosphere. 15) Which internal energy source produces heat by converting gravitational potential energy into thermal energy? A) accretion B) differentiation C) radioactivity D) both A and B E) all of the above 16) Which internal energy source is the most important in continuing to heat the terrestrial planets today? A) tidal heating B) radioactivity C) differentiation D) accretion E) all of the above 17) Heat escapes from the planet's surface into space by thermal radiation. Planets radiate almost entirely in the wavelength range of the A) infrared. B) visible. C) radio. D) ultraviolet. E) none of the above

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18) Which of the following best describes why the smaller terrestrial worlds have cooler interiors than the larger ones? A) They have relatively fewer radioactive elements. B) The smaller ones are farther from the Sun. C) They had more volcanic eruptions in the past, which released their internal heat. D) They have relatively more surface area compared to their volumes. E) They were cooler when they formed. 19) Which of the terrestrial worlds has the strongest magnetic field? A) Venus

B) Mars

C) the Moon

D) Mercury

E) Earth

20) Which two properties are most important in determining the surface temperature of a planet? A) internal temperature and atmosphere B) size and atmosphere C) size and chemical composition D) size and distance from the Sun E) distance from the Sun and atmosphere 21) How large is an impact crater compared to the size of the impactor? A) 10- 20 percent larger B) 1,000 times larger C) 100 times larger D) the same size E) 10 times larger 22) When we see a region of a planet that is not as heavily cratered as other regions, we conclude that A) the surface in the region is younger than the surface in more heavily cratered regions. B) there is little volcanic activity to create craters. C) the planet is rotating very slowly and only one side was hit by impactors. D) the surface in the region is older than the surface in more heavily cratered regions. E) the planet formed after the age of bombardment and missed out on getting hit by leftover planetesimals. 23) Steep- sided stratovolcanoes are made from lava that A) has a high viscosity.

B) has a medium viscosity.

C) can have any viscosity.

D) is as runny as liquid water.

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24) What type of stresses broke the earth's lithosphere into plates? A) internal temperature changes that caused the crust to expand and stretch B) impacts of asteroids and planetesimals C) cooling and contracting of the planet's interior, which caused the mantle and lithosphere to be compressed D) volcanism, which produced heavy volcanoes that bent and cracked the lithosphere E) the circulation of convection cells in the mantle, which dragged against the lithosphere 25) Which of the following describes tectonics? A) the eruption of molten rock from a planet's interior to its surface B) the wearing down or building up of geological features by wind, water, ice, and other phenomena of planetary weather C) the disruption of a planet's surface by internal stresses D) the excavation of bowl- shaped depressions by asteroids or comets striking a planet's surface 26) A planet is most likely to have tectonic activity if it has A) high surface gravity. B) low internal temperature. C) low surface gravity. D) a dense atmosphere. E) high internal temperature. 27) Why do we think Mercury has so many tremendous cliffs? A) They were probably formed by tectonic stresses when the entire planet shrank as its core cooled. B) They represent one of the greatest mysteries in the solar system, as no one has suggested a reasonable hypothesis for their formation. C) They probably formed when a series of large impacts hit Mercury one after the other. D) They were probably carved in Mercury's early history by running water. E) They are almost certainly volcanic in origin, carved by flowing lava. 28) Which of the following does not provide evidence that Mars once had flowing water? A) the presence of what looks like dried- up riverbeds B) the presence of impact craters that appear to have formed in mud C) some very old craters that appear to have been eroded by rain D) rocks of many different types jumbled together, as would occur if there had once been a great flood in the region, found by the Mars Pathfinder E) the presence of vast canals discovered in the late 1800s by Giovanni Schiaparelli and mapped by Percival Lowell

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29) How have we been able to construct detailed maps of surface features on Venus? A) by making computer models of geological processes on Venus B) by using radar from spacecraft that were sent to orbit Venus C) by studying Venus with powerful telescopes on spacecraft that were sent to orbit Venus D) by landing spacecraft on the surface for close- up study E) by studying Venus from Earth with powerful telescopes 30) Which of the following show evidence of ancient river beds? A) Mercury B) the Moon C) Venus D) Mars E) all of the above 31) Which of the following is not evidence for continental drift on Earth? A) similar rocks and fossils are found in different continents B) some continental boundaries fit together like pieces of a jigsaw puzzle C) high ocean ridges between the continents D) earthquakes E) the paucity of impact craters 32) What drives the motion of the continental plates on Earth? A) lava flows in trenches along the sea floor B) convection cells in the mantle C) the Coriolis force D) tidal forces E) the earth's magnetic field 33) Which of the following correctly describes the meaning of albedo? A) The higher the albedo, the more light the surface absorbs. B) The lower the albedo, the more light the surface reflects, and the less it absorbs. C) The higher the albedo, the more light the atmosphere absorbs. D) The higher the albedo, the more light the surface reflects, and the less it absorbs. E) The higher the albedo, the more light the surface emits. 34) Which of the following worlds has the most substantial atmosphere? A) Venus

B) the Moon

C) Earth

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D) Mercury

E) Mars

35) Which of the following worlds has the greatest difference in temperature between its "no atmosphere" temperature and its actual temperature? A) Venus

B) Earth

C) the Moon

D) Mercury

E) Mars

36) Earth's stratosphere is heated primarily by which process? A) Ozone absorbs visible sunlight. B) Atoms and molecules absorb infrared sunlight. C) Ozone is broken apart by ultraviolet radiation. D) Greenhouse gases absorb infrared radiation. E) Greenhouse gases are broken apart by X rays. 37) Suppose the earth's atmosphere had no greenhouse gases. Then the earth's average surface temperature would be A) 273 K, or about the freezing point for water. B) 283 K, or about 5 K cooler than it is now. C) 293 K, or about 5 K warmer than it is now. D) 288 K, or about the same as it is now. E) 250 K, which is well below freezing. 38) How does the greenhouse effect work? A) Greenhouse gases absorb infrared light from the Sun, which then heats the atmosphere and the surface. B) Greenhouse gases transmit visible light, allowing it to heat the surface, but then absorb infrared light from the earth, trapping the heat near the surface. C) Ozone transmits visible light, allowing it to heat the surface, but then absorbs most of the infrared heat, trapping the heat near the surface. D) Greenhouse gases absorb X rays and ultraviolet light from the Sun, which then heat the atmosphere and the surface. E) The higher pressure of the thick atmosphere at lower altitudes traps heat in more effectively. 39) The proper order of the layers of a generic atmosphere from lowest altitude to highest is A) stratosphere, troposphere, exosphere, thermosphere. B) stratosphere, troposphere, thermosphere, exosphere. C) troposphere, stratosphere, thermosphere, exosphere. D) troposphere, stratosphere, exosphere, thermosphere. E) none of the above

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40) The sky is blue because A) molecules scatter blue light more effectively than red light. B) the atmosphere transmits mostly blue light. C) molecules scatter red light more effectively than blue light. D) the atmosphere absorbs mostly blue light. E) the Sun mainly emits blue light. 41) Convection occurs in the troposphere but not in the stratosphere because A) the troposphere contains fewer greenhouse gases than the stratosphere. B) the troposphere is warmer than the stratosphere. C) the troposphere is cooler than the stratosphere. D) lower altitudes of the troposphere are warmer than higher altitudes, unlike in the stratosphere. E) higher altitudes of the troposphere are warmer than lower altitudes, unlike in the stratosphere. 42) How is the atmosphere of a planet affected by the rotation rate? A) Faster rotation rates raise the atmospheric temperature. B) Faster rotation rates raise surface temperatures and thus determine how much material is gaseous versus icy or liquid. C) The rotation rate determines how long the planet is able to retain its atmosphere. D) Faster rotation rates produce stronger winds. E) The rotation rate determines how much atmosphere a planet has. 43) Which of the following is not caused by the Coriolis effect on Earth? A) Objects moving southward in the Northern Hemisphere are deflected to the west. B) Objects moving northward in the Northern Hemisphere are deflected to the east. C) Water going down a drain swirls in opposite directions in the Northern and Southern hemispheres. D) Hurricanes swirl in opposite directions in the Northern and Southern hemispheres. E) The earth's circulation cells are split into three separate cells in each hemisphere. 44) Venus has a high albedo because its surface is covered by A) volcanic ash. B) snow. C) dust storms. D) light- colored rocks. E) clouds.

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45) Why does Mars have more extreme seasons than Earth? A) because it has a larger axis tilt B) because it has a more eccentric orbit C) because it has more carbon dioxide in its atmosphere D) because it is farther from the Sun E) all of the above 46) What is the main reason mountaintops are so cold? A) The winds are stronger at higher altitudes. B) There is more water vapor at higher altitudes, causing there to be more snow. C) The air is thinner at higher altitudes. D) Mountaintops are above much of the greenhouse gas in the atmosphere. E) All of the above are true. 47) Venus may have started with an ocean's worth of water. Where is its water now? A) The water changed to carbon dioxide through chemical reactions. B) Most of the water combined with rocks in chemical reactions. C) Most of the water is frozen beneath the surface. D) The water was lost when ultraviolet light broke apart water molecules and the hydrogen escaped to space E) The original water remains vaporized in the atmosphere due to Venus's intense heat. 48) Which of the following is not a product of outgassing? A) water B) sulfur dioxide C) oxygen D) carbon dioxide E) nitrogen 49) Earth's atmosphere contains only small amounts of carbon dioxide because A) the earth's volcanoes did not outgas as much carbon dioxide as those on Venus and Mars. B) most of the carbon dioxide was lost during the age of bombardment. C) chemical reactions with other gases destroyed the carbon dioxide and replaced it with the nitrogen that is in the atmosphere now. D) Earth doesn't have as strong a greenhouse effect as is present on Venus. E) carbon dioxide dissolves in water, and most of it is now contained in the oceans and carbonate rocks.

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50) What is differential rotation? A) when a planet's rotation changes due to a catastrophic event B) when a planet's rotation changes through evolution C) when storms in the northern hemisphere rotate counterclockwise while storms in the southern hemispher rotate clockwise D) when the core of a planet rotates at a different rate than its atmosphere E) when a body rotates faster or slower at its equator than it does at its poles 51) Why do jovian planets bulge around the equator, that is, have a "squashed" appearance? A) Their internal heat sources exert a pressure against the sides of the planets. B) Their large systems of moons and rings gravitationally attract the mass around the equator more. C) Their rapid rotation flings the mass near the equator outward. D) They are much more massive than the terrestrial planets. E) all of the above 52) How much energy does Jupiter emit compared with how much it receives from the Sun? A) It emits 1 percent as much. B) It emits twice as much. C) It emits 10 percent as much. D) It emits half as much. E) It emits 10 times as much. 53) How does Jupiter's core ...