PTYS/ASTR Section 2 - Spring 2007 Practice Exam 2

Transcription

1 PTYS/ASTR Section 2 - Spring 2007 Practice Exam 2 Note: The exam is scheduled for Thursday, March 29, It will be held in-class; you will have 75 minutes to finish the exam, though many of you will most likely not need the entire allotted time to complete the exam. Please remember to bring a #2 pencil to fill out the scantron answer sheet. The format of the exam will be 30 multiple-choice questions and 5 short-answer/essay questions. All material covered in class and in the textbooks from the first midterm test up through Tuesday, March 27, 2007 are fair game for the exam. (i.e. the exam is not cumulative) Part I - Multiple Choice 1. The Earth s albedo has been determined to be around This means A. 39% of the Sun s light is absorbed by the Earth. B. 39% of the Sun s light is reflected by the Earth back into space. C. 39% of the Earth s radiated light is absorbed by greenhouse gases. D. 39% of the Earth s radiated light escapes into space. 2. Which part of the Sun has the lowest temperature? A. the core B. the radiative zone C. the convective zone D. the photosphere E. the corona 3. The surface of Mercury looks most like A. the Moon B. Venus C. Earth D. Mars 4. Suppose that you read a news article about a huge solar explosion and they also show a picture of it as seen with a spacecraft instrument that measures x-rays. What part of the solar atmosphere is seen in the picture? A. photosphere B. chromosphere C. corona D. thermosphere 5. Why is it difficult to operate a spacecraft from the surface of Venus? A. The surface is entirely liquid, so the spacecraft must float. B. The surface is extremely cold, so the spacecraft s moving parts tend to freeze. C. The surface is extremely hot, so the spacecraft tends to melt. D. The surface is very rugged, so the spacecraft has to negotiate mountains, craters, and canyons just to get there.

2 6. What mechanism generates the Earth's magnetic field? A. Iron delivered by asteroid impacts is magnetic B. Circulation and convection of electrically conductive molten iron in the interior of the Earth C. The solar wind is magnetic, so it creates a magnetic field for the Earth as it passes by our planet. D. Lightning from the Earth's thunderstorms generates magnetic fields. 7. How do we know that part of the Earth's core is liquid? A. We have sent probes deep into the Earth. B. The Earth's oceans are being supplied by this reservoir today. C. There is a "shadow zone" where S-waves from a powerful earthquake are not detected on the other side of the Earth. D. Lava coming out from volcanoes is obviously liquid, thus everything inside the Earth has to be liquid. 8. If the Earth did not rotate on its axis, there would be no Coriolis Force. If that were to happen, what would be the effect on global atmospheric circulation? A. No effect. (Three circulation cells over one hemisphere.) B. The Earth's air would be stagnant -- no wind, no circulation cells. C. One global circulation cell in each hemisphere stretching from pole to equator. D. Multiple circulation cells would develop over each hemisphere, and the atmosphere would become very turbulent. 9. What specific physical effect was used to verify the existence of intense magnetic fields in sunspots? A. observation of ionized atoms in the region of the sunspots B. the Zeeman effect, the splitting of spectral absorption lines C. the measurement of relative strengths of spectral absorption lines from various atoms D. Doppler shift of light from sunspots 10. What caused the Moon to be in a 1:1 synchronous rotation with the Earth? A. simply a pure coincidence B. the magnetic field from the Earth interacts with iron on the Moon C. a giant impact from an asteroid spun the Moon into this fashion D. tidal forces from the Earth 11. How does Venus's atmosphere DIFFER from the Earth's? I. The atmospheric pressure at the surface II. The relative amount of carbon dioxide present III. The relative amount of oxygen present IV. The greenhouse effect is present A. I only B. I and II C. II, III, and IV D. I, II, and III E. I, II, III, and IV

3 12. Which of the following planets/satellites has a global (i.e. not localized in certain spots) magnetic field? I. Mercury II. Venus III. Earth IV. the Moon V. Mars A. III only B. I and III only C. III and IV only D. II, III, and V E. I, III, and V 13. Where can I find Gusev Crater, Valles Marineris, and Olympus Mons? A. Mercury B. Venus C. Earth D. Mars 14. Which planet fits the following description: Greenhouse Effect in its atmosphere, can t be seen at Midnight, about as big as the Earth? A. Mercury B. Venus C. Mars D. Jupiter 15. What is the character of the sunspot cycle? A. Sunspots increase and decrease in number over 11 years within a band of solar latitude between 10 and 30, with no discernible dependence of sunspot latitude upon time. B. Starting at sunspot minimum, new spots appear uniformly over the Sun but gradually, new spots become concentrated at midlatitudes as they increase and then decrease in number. C. Starting at sunspot minimum, new spots appear close to the equator, followed by newer spots farther from the equator until, when numbers decrease, they grow and decay at high latitudes. D. Starting at sunspot minimum, spots first appear far from the equator, followed by new spots appearing successively closer to the equator as they increase in number and finally, spots form close to the equator as numbers begin to decrease. 16. What is considered to be the most likely source for the deposits of ice that have been discovered at the lunar poles? A. the Moon s original shallow oceans B. comets that have crashed onto the lunar surface C. molten lava, because it releases water as it cools D. evaporation of subsurface water near the Moon s equator, and subsequent deposition near the poles

4 17. What are the Van Allen Belts? A. Regions of high-energy charged particles in the Earth s magnetosphere B. Regions of intense radiation above the Sun s photosphere C. a chain of craters found on the surface of the Moon D. an equatorial band of clouds that encircle Venus 18. How long does it take for the Moon to rotate once on its axis? A. it does not rotate because we see only one side of it from Earth B. approx. once every 14 days C. approx. once every 28 days D. approx. once every 56 days 19. If there were no carbon dioxide, water vapor, or methane in Earth's atmosphere, what would be the effect on Earth's surface temperature? A. It would be colder, below freezing. B. It would be the same. C. It would be slightly warmer. D. It would be much warmer, above the boiling point of water (like Venus). 20. Which of the following phenomena are caused by plate tectonics? I. Seafloor spreading II. Generation of long, large mountain ranges like the Himilayas III. the Earth's magnetic field IV. Formation of deep underground trenches A. II only B. I and III C. I, II, and III D. I, II, and IV 21. What is an aeolian process? A. Erosion caused by wind and/or water B. Erosion caused by chemical modification C. Erosion caused by humans D. Erosion caused by cratering 22. The polar caps on Mars are now known to consist of A. only H 2 O ice, which does not melt easily and survives the summer heat B. methane (CH 4 ), ammonia (NH 3 ), and water (H 2 O) ices, whose relative abundances vary with the seasons. C. only CO 2 ice, which is very volatile and melts easily. D. CO 2 ice overlying thicker H 2 O ice.

5 23. Where do the vast majority of earthquakes occur? A. In the middle of the oceans B. In the middle of the plates C. Along boundaries between nations D. Along boundaries between plates 24. You re an astronaut observing a new solar system. You notice that planet A has a surface nearly covered with craters, while planet B has relatively few craters. Both planets do not have an atmosphere, and are located relatively near each other. What can you easily conclude? A. Planet A is made mostly of iron, while planet B is made mostly of silicon. B. Planet A must have multiple moons, while planet B is moon-less. C. Planet A s surface is much older than Planet B s surface. D. Planet A has a magnetic field, while Planet B does not. E. Planet A has water on its surface, but Planet B does not. 25. What are the canals on Mars, as seen by Percival Lowell? A. an optical illusion B. canals cut by an advanced, but extinct, civilization C. cloud features D. rivers cut by once-flowing water on Mars 26. Greenhouse gases are opaque in which part of the electromagnetic spectrum? A. Ultraviolet B. Visible C. Infrared D. Microwave 27. Although Earth has probably retained much of the heat it had shortly after formation, it is also currently producing heat of its own too. What is the dominant process that accounts for this? A. Radioactive decay of elements within Earth s interior B. Heavy metals continuously fall into the center, creating more heat through friction C. Friction heating from the interaction of Earth s oceans with the upper crust which are slowing down Earth s rotation because of tidal forces with the moon. D. plate tectonics, creating friction and heat 28. Which of the following processes is not primarily powered by the Sun, either from its visible light energy or its tidal forces? A. Motion of Water in lakes and rivers B. Reshaping of the Earth's Surface C. Dynamics of the Earth's Atmosphere D. Life

6 29. How do surface temperatures vary on Venus? A. Essentially like Earth: there s a dayside and nightside temperature difference, and a pole-toequator temperature difference. B. Temperatures are constant from pole-to-equator, but there is a significant difference between night and day. C. Temperatures vary little from day-to-night, but there is a significant difference between pole and equator. D. Temperatures are essentially constant everywhere on Venus s surface, all of the time. 30. Which of the following signs of water is NOT seen on Mars? A. evidence of permafrost under the Martian surface B. water ice (as opposed to CO 2 ice) in the polar caps C. occasional clouds of ice crystals D. melting pools at the edges of the polar caps Part II - Short Answer 1 What is a planetary atmosphere? What types of planets are more likely to have an atmosphere? Name three things that an atmosphere does. 2 Explain the giant impact theory of the Moon's formation. Why is it the best theory on the formation of the Moon? 3 What is the origin of the lunar maria? 4 What is the Sun s role in global warming? 5 What are the three main reasons that Venus is such a bright object in our early morning or early evening sky? Spoiler Alert! Answers to multiple choice are on the next page...

7 Answers 1 B 2 D 3 A 4 C 5 C 6 B 7 C 8 C 9 B 10 D 11 D 12 B 13 D 14 B 15 D 16 B 17 A 18 C 19 A 20 D 21 A 22 D 23 D 24 C 25 A 26 C 27 A 28 B 29 D 30 D