2) Which of the following is smallest? A) size of a typical star B) 1 AU C) size of a typical planet D) 1 light-second Answer: C

Transcription

1 Physics 111 Exam 1 Fall 2013 Dr. S.G. Alexander Miami University Multiple Choice. Choose the one alternative that BEST completes the statement or answers the question, and mark the letter corresponding to your choice on your scan sheet. Only the scan sheet will be graded. 1) Which of the following statements does not use the term light-year in an appropriate way? A) It will take me light-years to complete this homework assignment. B) A light-year is about 10 trillion kilometers. C) It's about 4 light-years from here to Alpha Centauri. D) The Milky Way Galaxy is about 100,000 light-years in diameter. E) It will take the Voyager spacecraft about 20,000 years to travel just 1 light-year. 2) Which of the following is smallest? A) size of a typical star B) 1 AU C) size of a typical planet D) 1 light-second 3) You have taken a picture of a galaxy 1 billion light years away. That picture shows: A) a galaxy that is 13 billion years old. B) a galaxy that is 1 billion years old. C) a galaxy that is 1 billion light years old. D) a galaxy as it was 1 billion years ago. 4) When traveling north from the United States into Canada, you'll see the North Star (Polaris) getting. A) lower in the sky B) brighter C) higher in the sky D) dimmer 5) How does Earth's varying distance from the Sun affect our seasons? A) It is responsible for the fact that the seasons are opposite in the Northern and Southern hemispheres. B) It makes summer warmer in the Northern Hemisphere than in the Southern Hemisphere. C) It causes the seasons to be more extreme than they would be if the Earth's distance from the Sun were always the same. D) It doesn't Earth's orbital distance plays no significant role in the seasons. 6) It's 6 a.m. and the Moon is at its highest point in your sky (crossing the meridian). What is the Moon's phase? A) Full B) Third quarter C) First quarter D) New 7) What is a circumpolar star? A) a star that makes a daily circle around the celestial sphere B) A star that is visible from the Arctic or Antarctic circles C) a star that is close to the north celestial pole D) a star that is close to the south celestial pole E) a star that always remains above your horizon Answer: E 1

2 8) What makes the North Star, Polaris, special? A) It is the brightest star in the sky. B) It is the star directly on your northern horizon. C) It is the star straight overhead. D) It appears very near the north celestial pole. E) It can be used to determine your longitude on Earth. 9) Orion is visible on winter evenings but not summer evenings because of A) baseball on television. B) the tilt of Earth's axis. C) interference from the full moon. D) the precession of Earth's axis. E) the location of Earth in its orbit. Answer: E 10) Why is it summer in the Northern Hemisphere when it is winter in the Southern Hemisphere? A) The Northern Hemisphere is "on top" of Earth and therefore receives more sunlight. B) It isn't: both hemispheres have the same seasons at the same time. C) The Northern Hemisphere is tilted toward the Sun and receives more direct sunlight. D) The Northern Hemisphere is tilted away from the Sun and receives more indirect sunlight. E) The Northern Hemisphere is closer to the Sun than the Southern Hemisphere. 11) If the Moon is setting at 6 A.M., the phase of the Moon must be A) first quarter. B) third quarter. C) waning crescent. D) full. E) new. 12) What conditions are required for a solar eclipse? A) The phase of the Moon can be new or full, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun. B) The phase of the Moon must be new, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun. C) The phase of the Moon must be full, and the Moon's orbital plane must lie in the ecliptic. D) The phase of the Moon must be new, and the Moon's orbital plane must lie in the ecliptic. E) The phase of the Moon must be full, and the nodes of the Moon's orbit must be nearly aligned with Earth and the Sun. 13) In addition to the conditions required for any solar eclipse, what must also be true in order for you to observe a total solar eclipse? A) Earth must lie completely within the Moon's umbra. B) The Moon's penumbra must touch the area where you are located. C) Earth must be near aphelion in its orbit of the Sun. D) The Moon's umbra must touch the area where you are located. E) Earth must lie completely within the Moon's penumbra. 2

3 14) What causes the apparent retrograde motion of the planets? A) As Earth passes another planet, its gravitational pull slows down the other planet so that it appears to be traveling backward. B) Apparent retrograde motion is an illusion created by turbulence in Earth's atmosphere. C) When planets are farther from the Sun, they move slower than when they are nearer the Sun; it is during this slower period that they appear to move backwards. D) The other planets never really appear to move backward; the background stars shift due to Earth's revolution around the Sun. E) As Earth passes another planet, the other planet appears to move backward with respect to the background stars, but the planet's motion does not really change. Answer: E 15) What do astronomers mean by a constellation? A) A constellation is a group of stars related through an ancient story. B) A constellation is a group of stars that are all located in about the same place in space. C) A constellation is any random grouping of stars in the sky. D) A constellation is a region in the sky as seen from Earth. 16) What do we mean by a geocentric model of the universe? A) It is the name given to sphere-shaped models that show all the constellations as they appear in our sky on the celestial sphere. B) A model designed to explain what we see in the sky while having the Earth orbit the Sun C) A model of the Milky Way Galaxy that has our solar system located at its center D) A model designed to explain what we see in the sky while having the Earth located in the center of the universe 17) 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 planets in the wrong order going outward from the Sun. C) Copernicus used perfect circles for the orbits of the planets. D) Copernicus placed the Sun at the center, but did not realize that the Moon orbits the Earth. 18) Why did Ptolemy have the planets orbiting Earth on "circles upon circles" in his model of the universe? A) To properly account for the varying distances of the planets from Earth B) to explain the fact that planets sometimes appear to move westward, rather than eastward, relative to the stars in our sky C) To explain why Venus goes through phases as seen from Earth D) to explain why the Greeks were unable to detect stellar parallax E) to explain why more distant planets take longer to make a circuit through the constellations of the zodiac 19) The controversial book of this famous person, published in 1543 (the year of his death), suggested that Earth and other planets orbit the Sun. A) Tycho Brahe B) Kepler C) Copernicus D) Ptolemy E) Galileo 3

4 20) He discovered that Jupiter has moons. A) Kepler B) Aristotle C) Ptolemy D) Galileo E) Tycho Brahe 21) One of the "nails in the coffin" for the Earth-centered universe was A) Galileo's observation of stars in the Milky Way. B) the retrograde motion of the planets. C) eclipses of the Sun. D) Galileo's observations of the moons of Jupiter. E) the phases of the Moon. 22) From Kepler's third law, a hypothetical planet that is twice as far from the Sun as Earth should have a period of A) more than 2 Earth years. B) 2 Earth years. C) 1 Earth year. D) 1/2 Earth year. E) It depends on the planet's mass. 23) Kepler's second law, which states that as a planet moves around its orbit it sweeps out equal areas in equal times, means that A) a planet's period does not depend on the eccentricity of its orbit. B) planets have circular orbits. C) the period of a planet does not depend on its mass. D) a planet travels faster when it is nearer to the Sun and slower when it is farther from the Sun. E) planets that are farther from the Sun move at slower average speeds than nearer planets. 24) The point along a planet's orbit where it is closest to the Sun is called the orbit's A) period B) perihelion C) aphelion D) semi-major axis E) eccentricity 25) Which of the following statements about scientific theories is not true? A) A theory must make predictions that can be checked by observation or experiment. B) A theory is a model designed to explain a number of observed facts. C) A theory can never be proved beyond all doubt; we can only hope to collect more and more evidence that might support it. D) A theory cannot be taken seriously by scientists if it contradicts other theories developed by scientists over the past several hundred years. E) If even a single new fact is discovered that contradicts what we expect according to a particular theory, then the theory must be revised or discarded. 4

5 26) Match the accomplishment to the person: A) Tycho collected data, Kepler found elliptical orbits, Newton explained in terms of physics. B) Tycho collected data, Newton found elliptical orbits, Kepler explained in terms of physics. C) Kepler collected data, Tycho found elliptical orbits, Newton explained in terms of physics. D) Newton collected data, Kepler found elliptical orbits, Tycho explained in terms of physics. 27) Suppose an object is moving in a straight line at 50 mi/hr. According to Newton's first law of motion, the object will A) continue to move in the same way until it is acted upon by a force. B) continue to move in a straight line forever if it is in space, but fall to the ground if it is on Earth. C) eventually slow down and come to a stop. D) continue to move in the same way forever, no matter what happens. 28) According to the universal law of gravitation, the force due to gravity is A) directly proportional to the distance between objects. B) directly proportional to the square of the distance between objects. C) inversely proportional to the distance between objects. D) inversely proportional to the square of the distance between objects. E) not dependent on the distance between objects. 29) According to the universal law of gravitation, if you double the masses of both attracting objects, then the gravitational force between them will A) increase by a factor of 4. B) decrease by a factor of 4. C) not change at all. D) decrease by a factor of 2. E) increase by a factor of 2. 30) Newton showed that Kepler's laws are. A) actually only three of seven distinct laws of planetary motion B) seriously in error C) natural consequences of the law of universal gravitation D) the key to proving that Earth orbits our Sun 31) The astronauts feel weightless in the International Space Station, which orbits the Earth once every 90 minutes. Why? A) Because there is no gravity in space B) Because they are moving so fast C) Because they are falling around the Earth D) Because the gravity from the Moon cancels out the gravity from Earth 5

6 32) How are wavelength, frequency, and energy related for photons of light? A) Longer wavelength means lower frequency and higher energy. B) Longer wavelength means higher frequency and lower energy. C) Longer wavelength means lower frequency and lower energy. D) Longer wavelength means higher frequency and higher energy. E) There is no simple relationship because different photons travel at different speeds. 33) The wavelength of a wave is A) equal to the speed of the wave times the wave's frequency. B) the distance between where the wave is emitted and where it is absorbed. C) the distance between two adjacent peaks of the wave. D) how strong the wave is. E) the distance between a peak of the wave and the next trough. 34) From lowest energy to highest energy, which of the following correctly orders the different categories of electromagnetic radiation? A) visible light, infrared, X-rays, ultraviolet, gamma rays, radio B) gamma rays, X-rays, visible light, ultraviolet, infrared, radio C) radio, infrared, visible light, ultraviolet, X-rays, gamma rays D) radio, X-rays, visible light, ultraviolet, infrared, gamma rays E) infrared, visible light, ultraviolet, X-rays, gamma rays, radio 35) We can see each other in the classroom right now because we A) emit infrared light. B) reflect infrared light. C) reflect visible light. D) emit visible light. E) emit thermal radiation. 36) If you heat a gas so that collisions are continually bumping electrons to higher energy levels, when the electrons fall back to lower energy levels the gas produces A) an absorption line spectrum. B) an emission line spectrum. C) radio waves. D) X-rays. E) thermal radiation. 37) Suppose you see two stars: a blue star and a red star. Which of the following can you conclude about the two stars? Assume that no Doppler shifts are involved. (Hint: Think about the laws of thermal radiation.) A) The red star has a hotter surface temperature than the blue star. B) The red star is more massive than the blue star. C) The blue star is farther away than the red star. D) The blue star has a hotter surface temperature than the red star. E) The blue star is more massive than the red star. 6

7 38) Currently, the largest optical telescope mirrors have a diameter of A) 100 m. B) 5 m. C) 10 m. D) 2 m. E) 1 m. 39) Which of the following wavelength regions cannot be studied with telescopes on the ground? A) radio waves B) ultraviolet C) X-rays D) both B and C E) both A and C 40) In what wavelength range was interferometry first routinely used? A) ultraviolet B) infrared C) radio D) X-ray E) optical 41) Which of the following statements about X-rays and radio waves is not true? A) X-rays have higher frequency than radio waves. B) X-rays travel through space faster than radio waves. C) X-rays have shorter wavelengths than radio waves. D) X-rays and radio waves are both forms of light, or electromagnetic radiation. 42) Which of the following conditions lead you to see an absorption line spectrum from a cloud of gas in interstellar space? A) The cloud is visible primarily because it reflects light from nearby stars. B) The cloud is cool and lies between you and a hot star. C) The cloud is extremely hot. D) The cloud is cool and very dense, so that you cannot see any objects that lie behind it. 43) Studying a spectrum from a star can tell us a lot. All of the following statements are true except one. Which statement is not true? A) The total amount of light in the spectrum tells us the star's radius. B) We can identify chemical elements present in the star by recognizing patterns of spectral lines that correspond to particular chemicals. C) The peak of the star's thermal emission tells us its temperature: hotter stars peak at shorter (bluer) wavelengths. D) Shifts in the wavelengths of spectral lines compared to the wavelengths of those same lines measured in a laboratory on Earth can tell us the star's speed toward or away from us. 44) How does the light-collecting area of an 8-meter telescope compare to that of a 2-meter telescope? A) The 8-meter telescope has 8 times the light-collecting area of the 2-meter telescope. B) The 8-meter telescope has 16 times the light-collecting area of the 2-meter telescope. C) The 8-meter telescope has 4 times the light-collecting area of the 2-meter telescope. D) The answer cannot be determined from the information given in the question. 7

8 45) The angular separation of two stars is 0.1 arcseconds and you photograph them with a telescope that has an angular resolution of 1 arcsecond. What will you see? A) You will see two distinct stars in your photograph. B) The stars will not show up at all in your photograph. C) The photo will seem to show only one star rather than two. D) The two stars will appear to be touching, looking rather like a small dumbbell. 46) Which of the following would be the most capable ultraviolet telescope? A) A 30 meter telescope, on a mountain B) A 10 meter telescope, on a mountain C) A 2.5 meter telescope, in space D) A 4 meter telescope, in space 47) In the book, Heavenly Intrigue, it is argued that Kepler poisoned Tycho with A) calcium B) lead C) arsenic D) cyanide E) mercury Answer: E 48) Why are planetary orbits ellipses? A) That's what Kepler showed they are. B) They aren't; they're really circular. C) The gravitational force between the Sun and the planets varies as 1/distance2 D) The gravitational force is weaker for more distant planets. E) Circular orbits don't agree with observations 49) The person who was responsible for getting Newton to publish his work on motion and gravity in the Principia was A) Robert Hooke B) King Charles II C) Galileo D) Edmund Halley E) John Locke 50) The proposed successor to the Hubble Space Telescope which will be launched in a few years is named the A) James Webb Telescope B) Keck Telescope C) Palomar Telescope D) Johannes Kepler Telescope E) Stephen Hawking Telescope 8