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Key1b - KEY MIDTERM#1 Astronomy 201 Fall 2009...

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Unformatted text preview: KEY MIDTERM #1 Astronomy 201 Fall 2009 Prof. Bechtold Sept. 22, 2009 Read each question carefully, and answer on the Scantron sheet provided. Although some questions are similar to questions in the practice quizzes, they are NOT identical. There are 50 questions. Each question is worth 1 point. Each question has only one right answer. GOOD LUCK! YOUR EXAM IS VERSION B 1. This exam is VERSION b. B 2. Which of the following is largest? a. The Milky Way b. The Solar System c. The Virgo Cluster of Galaxies d. The Local Group e. one astronomical unit Answer: c. One astronomical unit is the distance between the Earth and Sun, which is smaller than the Solar system. The Milky Way is one galaxy in the Local Group, which is larger. The Virgo Cluster is the large cluster into which we are falling. 3. How does the light ­collecting area of an 8 ­meter telescope compare to that of a 2 ­ meter telescope? a. The answer cannot be determined from the information given in the question. b. The 8 ­meter telescope has 4 times the light ­collecting area of the 2 ­meter telescope. c. The 8 ­meter telescope has 8 times the light ­collecting area of the 2 ­meter telescope. d. The 8 ­meter telescope has 16 times the light ­collecting area of the 2 ­meter telescope. e. The 8 ­meter telescope has ¼ the light ­collecting area of the 2 meter telescope. Answer: d. The light collecting area depends on the area of the telescope. A telescope with a diameter of 8 meters has 16 times more area than a telescope with a diameter of 2 meters 4. A light year is a unit of a. time b. distance c. force d. velocity e. acceleration Answer: b. A light year is the distance that light travels in one year. 5. When Copernicus first created his Sun ­centered model of the universe, it did not lead to substantially better predictions of planetary positions than the Ptolemaic model. Why not? a. Copernicus misjudged the distances between the planets. b. Copernicus placed the Sun at the center, but did not realize that the Moon orbits the Earth. c. Copernicus used perfect circles for the orbits of the planets. d. Copernicus placed the planets in the wrong order going outward from the Sun. e. Copernicus didn’t know about the law of gravity. Answer: c. The actual orbits are ellipses, not circles 6. In scientific notation, the number 1,000,000,000 is a. 1.0 x 10 ­9 b. 1.0 x 10 ­6 c. 1.0 x 10 ­3 d. 1.0 x 103 e. 1.0 x 109 Answer: e. 7. The ________________ is everything that exists. a. Solar system b. Milky Way c. Local Group d. Local Supercluster e. Universe Answer: e. The solar system is the Sun + planets. The Milky Way is the galaxy in which our Solar System is located. The Local group is the Milky Way, Andromeda and a few other galaxies, and is part of a larger system of galaxies called the Local Supercluster. The Universe, is, by definition, everything in the physical world. 8. The ancient Greek who correctly deduced that the Moon was much closer to the Earth than the Sun was a. Aristotle b. Ptolemy c. Tycho d. Aristarcus e. Copernicus Answer: d 9. In the following diagram, which shows what we call a quarter moon? A. B. C. D. a. A b. B c. C d. D e. None of the above Answer: A. B is a GIBBOUS moon, C is a crescent, D is the full moon. 10. An early written cosmology which held that the Universe was cyclic in nature was called a. The Hindu Rig Veda b. The Mysterium Cosmographicum c. The Book of Genesis d. The Cosmic Context e. The Dialogue of the Two World Systems Answer: a. 11. In the Local Group, the two largest galaxies are called a. The Milky Way and Andromeda b. The Large Magellanic Cloud and Small Magellanic Cloud c. Quaor and Sedna d. Pluto and Charon e. Virgo and Orion Answer: a. The Milky Way and Andromeda. Pluto, Charon, Quaor and Sedna are objects in our Solar System. The Large and Small Magellanic Clouds are dwarf galaxies orbiting the Milky Way. Virgo and Orion are constellations. 12. During the period of each year when we see Mars undergoing retrograde motion, what is going on? a. The Earth and Mars are at opposite sides of the Sun. b. The Earth is catching up with, and passing by Mars in our respective orbits c. Mars is standing still d. The Earth is standing still e. Mars is reversing its direction of orbit around the Sun Answer: b 13. One reason to prefer the Copernican model for the solar system over the Ptolemaic one is a. Compactification b. Evolution c. Reductionism d. Occam's Razor e. Determinism Answer: d. Occam’s Razor. The simpler explanation is the best explanation 14. The Islamic calendar is based on a. The orbit of the Earth around the Sun b. The orbit of the Moon around the Earth c. The orbit of the Sun around the Milky Way d. The orbit of the Moon around the Earth and the orbit of the Earth around the Sun. e. The rotation of the Moon. Answer: b. The orbit of the moon. 15. Radio astronomers combine light from widely spaced telescopes in order to make sharp images, a technique called a. resolution b. seeing c. chaos d. interferometry e. chromatic aberration Answer: d. 16. When we used the infrared camera in class, the ice cubes appeared dark because a. water absorbs infrared light b. ice reflects less infrared light than the rest of the room c. ice is colder than the rest of the room d. ice reflects more infrared light than the rest of the room e. ice emits mostly visible light Answer: c. Ice is cold, and does not emit much infrared light. 17. If we say that a material is opaque to infrared light, we mean that a. it emits infrared light b. it transmits infrared light c. it reflects infrared light d. it absorbs infrared light e. none of the above Answer: d. opaque is the opposite of transparent. 18. The age of the Earth is about a. 4.5 thousand years b. 4.5 million years c. 4.5 billion years d. 14 billion years e. 100 billion years Answer: c. 19. If R is the distance between two gravitating bodies, then the force of gravity produced by one on the other is a. proportional to R b. proportional to R2 c. inversely proportional to R d. inversely proportional to R2 e. independent of R Answer: d. 20. Astronomers use the Doppler shift to measure a. the temperature of celestial objects b. the size of celestial objects c. the shape of celestial objects d. the age of celestial objects e. the radial velocity of celestial objects Answer: e. 21. Newton’s third law of motion is a. for every action there is an equal and opposite reaction b. the gravitational force is proportional to the mass c. an imaginary line connecting the Sun to any planet sweeps out equal areas in equal time. d. the solar system is chaotic e. The Moon orbits the Earth in an elliptical orbit. Answer: a. 22. The ancient Greek astronomer who first gave reasons why the Earth is spherical was a. Aristotle b. Ptolemy c. Tycho d. Aristarcus e. Copernicus Answer: a 23. The four fundamental forces of Nature are a. Gravity, Electro ­magnetism, Weak, Quantum b. Gravity, Electro ­magnetism, Weak, Strong c. Gravity, Electro ­magnetism, Strings, Quarks d. Gravity, Electro ­magnetism, Plank, Doppler e. none of the above. Answer: b 24. In string theories, the Universe is a. 10 dimensional b. 2 dimensional c. 36 dimensional d. 4 dimensional e. imaginary Answer: a. 25. Fractals are a. self ­similar b. never seen in nature c. 10 ­dimensional d. Keplerian e. none of the above Answer: a. self ­similar. They look the same on all scales. 26. This is a picture of a. The Milky Way Galaxy b. The Mandelbrot Set c. The Julia Fractal d. A Calabi ­Yau figure e. A cosmic string Answer: c. 27. The person who first used a telescope to observe the Sun and Jupiter's moons was a. Ptolemy b. Copernicus c. Newton d. Galileo e. Laplace Answer: d. Galileo 28. The photoelectric effect is evidence that a. photons are waves b. atoms are made of quarks c. light can be described as streams of particles d. the speed of light is never greater than 300,000 km/sec e. Newton’s Laws of Motion are correct Answer: c. The photoelectric effect is an example of a phenomenon where light acts like particles, not waves. 29. The fact that some predictions for physical systems are very sensitive to initial conditions is called a. self ­similarity b. the Butterfly Effect c. Keplerian motion d. the Calabi ­Lau Effect e. Occam’s razor Answer: b. If a butterfly flaps its wings in China, does is change the weather in New York? 30. Periodic oscillations of electromagnetic fields are called a. heat b. light c. chromatic aberration d. turbulance e. sound Answer: b. 31. Because we live on Earth, our eyes have evolved to be sensitive to a. Gamma Rays b. X ­rays c. Ultraviolet light d. Visible light e. Infrared Light Answer: d. 32. Laplace’s world view can be described as a. deterministic b. geocentric c. chaotic d. erratic e. recursive Answer: a. deterministic. He didn’t think the solar system was chaotic. 33. Turbulance in the air causes blurring of images of celestial objects, an effect which astronomers call a. resolution b. seeing c. chaos d. interferometry e. chromatic aberration Answer: b. 34. Telescope mirrors are parabolic in order to a. avoid the effects of bad seeing b. focus light into a point c. be easier to clean d. focus optical light but not infrared light e. none of the above Answer: b. 35. One of the reasons astronomers use cameras sensitive to infrared light is a. they are cheaper than cameras sensitive to visible light b. they let us see through the dust that obscures visible light c. they let us see objects as they will be in the future d. they let us see fainter objects than similar cameras that are sensitive to visible light e. they let us see smaller objects than similar cameras that are sensitive to visible light Answer: b. 36. The Earth orbits the Sun a. in a perfect circle b. in an ellipse with the Sun at the center c. in an ellipse with the Sun at one focus d. in a shape called an epicycle e. in a shape called a deferent Answer: c 37. What is an extrasolar planet? a. a planet bigger than the Sun b. a planet that orbits a star that is not our Sun. c. a planet that is part of the Kuiper belt d. a planet that used to be part of our solar system but now is part of the Oort comet cloud e. none of the above Answer: b. 38. How have most extrasolar planets been discovered? a. by direct exporation with a robotic spacecraft b. by very sharp pictures taken with the Hubble Space telescope c. by measuring periodic Doppler shifts of stellar spectra d. by radio imaging e. by taking pictures of the planets in the X ­rays Answer: c. 39. How soon will we be sending astronauts to explore Alpha Centauri? a. In the next decade, this is a major new goal of NASA b. Early next year, the Chinese will launch astronauts to visit Alpha Centauri. c. It will take several decades to build a spacecraft and train the astronauts, but all the technology is in place to do it. d. Astronauts have already visited Alpha Centauri. e. Astronauts will never be able to visit Alpha Centauri. Answer: e. It will take many thousands of years for any rocket to get to Alpha Centauri. 40. How long does it take the Earth to complete one orbit around the Sun? a. one day b. one month c. one light year d. one year e. 26,000 years Answer: d. 41. In science, a broad idea or picture that has been repeatedly verified so as to give us great confidence that it represents reality is called a. a theory b. an observation c. an epicycle d. a quark e. a deferent Answer: a. 42. I observe that a star has a parallax of 0.5 arcsecond. What does this tell me about the star? a. It’s 0.25 parsec away. b. The light I see from it left the star 0.5 seconds ago. c. It’s 0.5 parsec away. d. It’s hotter than the Sun e. It’s 2 parsec away. Answer: e. d = 1/p 43. Emission and absorption lines in the spectra of celestial objects can be used to a. measure transverse velocities of the objects b. measure radial velocities of the objects c. measure what type of atoms are in the objects d. all of the above e. b and c but not a Answer: e. 44. What is the “celestial sphere”? a. The celestial sphere is a representation of how the sky looks as seen from Earth. b. It represents a belief in an Earth ­centered universe, and hence is no longer considered to have any use. c. It is a model of how the stars are arranged in the sky relative to our Sun, which is in the middle of the sphere. d. The celestial sphere is a model that shows the true locations of the Sun and a few thousand of the nearest stars. e. It is a mechanical model of the solar system, used to predict the position of planets in the future. Answer: a 45. The planets never travel in straight lines as they orbit the Sun. According to Newton's second law of motion, this must mean that a. The planets will eventually fall into the Sun. b. The planets have Doppler shifts. c. A force is acting on the planets. d. The planets are always accelerating. e. The planets are really fractal in shape. Answer: c. 46. Suppose you know the frequency of a photon, and the speed of light. What else about the photon can you determine? a. Its acceleration. b. Its temperature. c. Its age. d. Its wavelength and energy. e. all of the above Answer: d. 47. From shortest to longest wavelength, which of the following correctly orders the different categories of electromagnetic radiation? a. Gamma rays, X rays, visible light, ultraviolet, infrared, radio b. Infrared, visible light, ultraviolet, X rays, gamma rays, radio c. Gamma rays, X rays, ultraviolet, visible light, infrared, radio d. Radio, infrared, visible light, ultraviolet, X rays, gamma rays e. None of these are correctly ordered. Answer: c. 48. Which of the following statements best describes the difference between a refracting telescope and a reflecting telescope? a. It is much easier to make a large refracting telescope than a large reflecting telescope. b. A refracting telescope produces refracted images while a reflecting telescope produces reflected images. c. Reflecting telescopes make much clearer images than can refracting telescopes of the same size. d. A refracting telescope uses a transparent glass lens to focus light while a reflecting telescope uses a mirror to focus light. e. Refracting telescopes are the only types of telescopes which can be launched into space. Answer: d. 49. You observe a distant galaxy. You find that a spectral line, resulting from an electron transition in hydrogen, is shifted from its normal location in the visible part of the spectrum into the infrared part of the spectrum. What can you conclude? a. The galaxy has very weak gravity. b. The galaxy is made purely of hydrogen. c. The galaxy is moving towards you. d. The galaxy is moving away from you. e. The galaxy is circumpolar. Answer: d. 50. The great contribution of Tycho Brahe was to _________. a. observe planetary positions with sufficient accuracy so that Kepler could later use the data to discover the laws of planetary motion b. offer the first detailed model of a Sun ­centered solar system, thereby beginning the process of overturning the Earth ­centered model of the Greeks c. discover that planets orbit the Sun in elliptical orbits with varying speed d. discover four moons orbiting Jupiter, thereby lending strong support to the idea that the Earth is not the center of the universe e. advocate epistemological parsimony. Answer: a. ...
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