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Final Exam: June 2015 Number of pages: 18
Course: ASTR 1P01 Number of students:
Examination date: 6 June 2015 Time limit: 2 hours Time of Examination: 9:00 – 11:00 Instructor: S. D’Agostino
Answer all questions on the scantron sheet provided.
No aids are permitted except for a non-programmable calculator. Use or pos- session of unauthorized materials will automatically result in the award of a zero grade for this examination.
Return both the exam script and your scantron sheet when you leave the exam room.
Each question is worth 1 mark. Total number of marks: 100.
1. Jupiter’s diameter is about times as large as Earth’s diameter.
(a) 2 (b) 10
(c) 100 (d) 1000
2. The radius of Saturn’s orbit around the Sun is about times as large as the radius of Earth’s orbit around the Sun.
(a) 2 (b) 10
(c) 100 (d) 1000
3. The mass of the Sun is about times the mass of the Earth.
(a) 2 (b) 10
(c) 100 (d) 1000
(e) [The mass of the Sun is much greater than any of the numbers listed above.]
4. It takes light emitted from the Sun approximately to reach the Earth.
(a) 8 seconds (b) 8 minutes
(c) 8 hours (d) 8 days
5. The speed of light in vacuum is approximately (a) 300,000 km/year.
(b) 300,000 km/h.
(c) 300,000 km/min.
(d) 300,000 km/s.
(e) much faster than any of the other alternatives listed here.
6. One astronomical unit (1 AU) is approximately equal to (a) 150,000 km.
(b) 150,000,000 km.
(c) 150,000,000,000 km.
(d) 150,000,000,000,000 km.
7. Ancient astronomers believed the planets are special compared to stars because (a) planets repeat the same orbits each year.
(b) planets are made of rock, whereas stars are made of gas.
(c) many of them resemble Ralph Wiggum.
(d) over time, planets appear to move against the relatively fixed background stars.
8. Which of the following astronomical systems is/are held together by gravity?
(a) The Sun.
(b) The Solar System.
(c) The Milky Way.
(d) The Local Group.
(e) All of them are.
9. The four fundamental forces are
(a) gravity, levity, holonomy, and Donald Trump’s urge to evict poor widows from their apartments.
(b) gravity, electricity, the strong force, and the New England Patriot’s urge to un- necessarily cheat.
(c) gravity, electromagnetism, the strong nuclear force, and the weak nuclear force.
(d) gravity, electromagnetism, hydrodynamics, and quarks.
10. The best understanding we currently have about the origin of the universe is that it began
(a) with a whimper.
(b) with a mysterious change to a Las Vegas betting line.
(c) with a big bang.
(d) with a big crunch.
11. The approximate number of stars in the Milky Way galaxy is (a) 100 thousand.
(b) 100 million.
(c) 100 billion.
(d) 100 trillion.
12. Most of the solar system’s asteroids are located in a region between the orbits of Mars and Jupiter called
(a) the asteroid zone.
(b) the asteroid alley.
(c) the asteroid yard.
(d) the asteroid belt.
13. We do not see lunar eclipses every time the Moon is full because (a) the Moon is usually on the wrong side of the Earth to be seen.
(b) the Moon’s orbit is tilted relative to the Earth’s orbit around the Sun.
(c) sometimes lunar eclipses occur when the Moon is in a different phase.
(d) the Moon often produces so much light that it fills in the Earth’s shadow.
(e) the Moon can only be eclipsed once every 18 years.
14. When the Moon’s phase is new, the Moon rises at about (a) sunrise.
(b) mid-day.
(c) sunset.
(d) midnight.
15. When the Moon’s phase is first quarter, the Moon rises at about (a) sunrise.
(b) mid-day.
(c) sunset.
(d) midnight.
16. When the Moon’s phase is full, the Moon rises at about (a) sunrise.
(b) mid-day.
(c) sunset.
(d) midnight.
17. When the Moon’s phase is third quarter, the Moon rises at about (a) sunrise.
(b) mid-day.
(c) sunset.
(d) midnight.
18. When the Moon sets between sunrise and mid-day, its phase is (a) waxing crescent.
(b) waxing gibbous.
(c) waning gibbous.
(d) waning crescent.
19. When the Moon sets between mid-day and sunset, its phase is (a) waxing crescent.
(b) waxing gibbous.
(c) waning gibbous.
(d) waning crescent.
20. When the Moon sets between sunset and midnight, its phase is (a) waxing crescent.
(b) waxing gibbous.
(c) waning gibbous.
(d) waning crescent.
21. When the Moon sets between midnight and sunrise, its phase is (a) waxing crescent.
(b) waxing gibbous.
(c) waning gibbous.
(d) waning crescent.
22. Solar eclipses occur approximately once or twice per (a) year.
(b) decade.
(c) century.
(d) millennium.
23. Lunar eclipses occur approximately once or twice per (a) year.
(b) decade.
(c) century.
(d) millennium.
24. On the summer solstice in the northern hemisphere, the Sun rises (a) directly east.
(b) north of east.
(c) south of east.
(d) [It depends on your exact location in the northern hemisphere.]
25. On the winter solstice in the northern hemisphere, the Sun rises (a) directly east.
(b) north of east.
(c) south of east.
(d) [It depends on your exact location in the northern hemisphere.]
26. On an equinox in the northern hemisphere, the Sun rises (a) directly east.
(b) north of east.
(c) south of east.
(d) [It depends on your exact location in the northern hemisphere.]
27. The fact that the Earth is spherical was first deduced by (a) Aristotle.
(b) Galileo.
(c) Kepler.
(d) Christopher Columbus.
28. The radius of the Earth was first estimated by (a) Alexander the Great.
(b) Eratosthenes.
(c) Newton.
(d) Christopher Columbus.
29. The relative sizes of the Earth, Moon, and Sun were first estimated by (a) Hippolyte the Not-So-Great.
(b) Aristarchus.
(c) Copernicus.
(d) Newton.
30. The strongest ancient argument in favour of an Earth-centred solar system was that (a) the Earth was too massive to move.
(b) it would be much more windy on Earth if it moved.
(c) stellar parallax was not observed.
(d) the Sun was the ruler of the Earth in ancient mythology.
31. The planets have unusual apparent motions, in that they
(a) zig-zag, as if they are being pursued by threatening predators.
(b) spiral, as if they are being flushed down a toilet bowl.
(c) sometimes rise in the east and sometimes rise in the west.
(d) sometimes move from east-to-west relative to the stars, and sometimes move from west-to-east relative to the stars.
32. The apparent motions of the planets (a) are always close to the ecliptic.
(b) are close to the ecliptic in some seasons, but far from the ecliptic in others.
(c) are in various parts of the sky, somewhat like bees buzzing around a beehive.
(d) are always in planes, but the planes are oriented randomly in the sky.
33. The reason for the apparent retrograde motions of the planets is that
(a) sometimes the gears in the celestial spheres get “stuck,” and it takes a few weeks for them to move normally again.
(b) some planets have nostalgia for the 1970s and therefore occasionally “go retro.”
(c) some planets sometimes orbit the Sun in the sense opposite to Earth’s orbital sense.
(d) the Earth moves at a different speed and in a different orbit compared to other planets.
34. The Earth-centred model of the solar system was developed to its highest degree by (a) Pandora.
(b) Plato.
(c) Ptolemy.
(d) Pythagoras.
35. The Sun-centred model of the solar system, which was originally championed by , was revived in the Renaissance by .
(a) Hipparchus, Galileo (b) Almagest, Kepler
(c) Ra, Sheed
(d) Aristarchus, Copernicus
36. The greatest naked-eye observer in the history of astronomy was (a) Tycho Brahe (but only by a nose).
(b) Nicolaus Copernicus.
(c) Galileo Galilei.
(d) Johannes Kepler.
(e) Isaac Newton.
37. After many years of number-crunching, determined that the orbits of the planets were ellipses, and he also determined relationships satisfied by various proper- ties of the planetary orbits.
(a) Tycho Brahe
(b) Nicolaus Copernicus (c) Galileo Galilei (d) Johannes Kepler
(e) Mary Wollstonecraft
38. Convincing evidence that the Sun is the centre of the solar system was obtained thanks to the careful observations of
(a) Richard Feynman.
(b) Galileo Galilei.
(c) Murray Gell-Mann.
(d) Shaquille O’Neal.
(e) Lemon Verbena.
39. Ockham’s razor is
(a) now available with new-and-improved twin-blades!
(b) a device used by ancient Greek astronomers to measure the angle between the Sun and the planets.
(c) another term used to describe the heliocentric model of the solar system.
(d) a metaphor for the process of discriminating between scientific models based on their relative simplicity.
40. Newton’s first law of motion states that
(a) if the big game is on TV, I ain’t getting off the couch.
(b) if the net force acting on an object is zero, then the object maintains its state of continuous rest or its state of motion at a constant speed.
(c) if the net force acting on an object is zero, then the object maintains its state of continuous rest or its state of motion in a straight line at a constant acceleration.
(d) if the net force acting on an object is zero, then the object maintains its state of continuous rest or its state of motion in a straight line at a constant speed.
41. The Moon maintains a (nearly) circular orbit around the Earth because
(a) it fears being sued by Donald Trump and forced to prove that it really was born in the U.S.
(b) of Newton’s first law of motion, which says that a body in motion will continue in motion at a constant speed as long as the net force acting on it is zero.
(c) of the gravitational force exerted on it by the Earth.
(d) the Earth and Moon form a gravitational Fourier-transform pair.
42. Newton’s second law of motion states that the acceleration of an object is
(a) directly proportional to the net force acting on it and inversely proportional to its velocity.
(b) directly proportional to its velocity and inversely proportional to the net force acting on it.
(c) directly proportional to the net force acting on it and inversely proportional to its mass.
(d) directly proportional to its mass and inversely proportional to the net force acting on it.
43. Newton’s second law of motion states that the direction of an object’s is the same as the direction of the .
(a) acceleration, velocity
(b) acceleration, net force exerted on the object (c) acceleration, speed
(d) velocity, net acceleration exerted on the object 44. Newton’s third law states that
(a) if you break the first two laws, then Donald Trump will sue you unless you promise not to break the third law.
(b) when two objects interact, the more massive one exerts a greater force on the less massive one, in the same ration as the masses.
(c) when two objects interact, each exerts a force on the other, and the two forces have the same magnitude and opposite directions.
(d) when two objects interact, and the forces each exerts on the other are directly proportional to the masses of the objects and the square of the distance separating the objects.
45. If the net force acting on a moving object is not zero, then
(a) the object will remain moving at the same speed in the same direction.
(b) the object will speed up.
(c) the object will slow down.
(d) the object might speed up, might slow down, or might change direction, depending on the direction of the force.
46. If the masses of the Earth and the Moon were to suddenly double, while the distance between them remained the same, then the gravitational force on each of them exerted by the other would
(a) increase by a factor of 2.
(b) decrease by a factor of 2.
(c) increase by a factor of 4.
(d) decrease by a factor of 4.
(e) [There would be no change in the gravitational force.]
47. Different colours of light have different (a) masses.
(b) accelerations.
(c) forces.
(d) wavelengths.
48. If the masses of the Earth and the Moon were to suddenly double, and the distance between them also doubled, then the gravitational force on each of them exerted by the other would
(a) increase by a factor of 2.
(b) decrease by a factor of 2.
(c) increase by a factor of 4.
(d) decrease by a factor of 4.
(e) [There would be no change in the gravitational force.]
49. Imagine a single planet orbiting a star. If the star were to suddenly disappear, then the planet would
(a) continue its orbit unchanged.
(b) fall immediately towards the centre, in a straight line.
(c) fall immediately towards the centre, in a spiral.
(d) fly radially outwards, moving in a straight line.
(e) fly off “on a tangent,” moving in a straight line.
50. The visible spectrum
(a) usually beats the invisible spectrum in a fight, unless it takes place in the dark.
(b) is an instrument that is attached to telescopes to gather light from faint galaxies.
(c) is a diffraction grating used to calibrate visible light.
(d) is the part of the electromagnetic spectrum that is visible to humans.
51. White light
(a) has a frequency between red light and green light.
(b) has a wavelength between yellow light and blue light.
(c) is a combination of all colours.
(d) is emitted in large quantities from black lights.
52. Infrared light
(a) has a wavelength that is shorter than visible light.
(b) has a wavelength that is longer than visible light.
(c) has a wavelength that is in the range of visible light.
53. Ultraviolet light
(a) has a wavelength that is shorter than visible light.
(b) has a wavelength that is longer than visible light.
(c) has a wavelength that is in the range of visible light.
54. The energy of a photon depends on its wavelength, and photons with (a) longer wavelength carrying more energy.
(b) longer wavelength carrying less energy.
(c) [Photon energy depends on frequency, not wavelength.]
55. As the temperature of a glowing object increases, the object radiates electromagnetic waves more strongly at
(a) longer wavelengths.
(b) shorter wavelengths.
(c) [The wavelengths of emitted radiation do not depend on the temperature of the glowing object.]
56. Electromagnetic radiation is emitted from an individual neutral atom when (a) the atom moves about with greater speed.
(b) the atom moves about with greater temperture.
(c) an electron in the atom moves faster.
(d) an electron in the atom makes a transition from a higher-energy level to a lower- energy level.
57. The discrete emission spectrum of a glowing object can be used to determine (a) the chemical elements contained in the glowing object.
(b) the temperature of the object.
(c) how far away the object is.
(d) the chemical elements contained in the atmosphere of the glowing object.
58. The continuous spectrum of a glowing object can be used to determine (a) the chemical elements contained in the glowing object.
(b) the temperature of the object.
(c) how far away the object is.
(d) the chemical elements contained in the atmosphere of the glowing object.
59. The discrete absorption spectrum of a glowing object can be used to determine (a) the chemical elements contained in the glowing object.
(b) the temperature of the object.
(c) how far away the object is.
(d) the chemical elements contained in the atmosphere of the glowing object.
60. In vacuum, which type of electromagnetic radiation travels at the greatest speed?
(a) visible light (b) ultraviolet light
(c) infrared light (d) gamma rays
(e) [All electromagnetic waves travel at the same speed in vacuum.]
61. If an object has spectral lines shifted to longer wavelengths, then the object is (a) moving away from us.
(b) moving towards us.
(c) maintaining the same distance to us.
(d) not moving.
62. Do astronomers use ground-based X-ray telescopes?
(a) Yes, because they can penetrate gas clouds.
(b) No, because no astronomical objects emit X-rays.
(c) No, because X-rays cannot get through the Earth’s atmosphere.
(d) No, because astronomers have not yet devised detectors for X-rays.
63. The two main types of optical telescopes in common use are (a) reflectors and diffractors.
(b) reflectors and refractors.
(c) refractors and diffractors.
(d) objectives and injectives.
64. The most important factor in a good-quality telescope is (a) the diameter of the objective.
(b) the focal length of the objective.
(c) the magnification of the eyepiece.
(d) the shutter speed of the telescope’s camera.
65. A telescope’s resolving power measures its ability to see (a) fainter sources.
(b) more distant sources.
(c) finer details in sources.
(d) larger sources.
(e) more rapidly moving sources.
66. Light travels in glass than in air.
(a) slower (b) faster
(c) at the same speed
67. An interferometer is used so that
(a) two widely-spaced mirrors act like one giant telescope with increased collecting area.
(b) two widely-spaced mirrors act like one giant telescope with increased resolving power.
(c) by putting one mirror above the other the instrument can be made much smaller.
(d) light can be detected at wavelengths not available to single telescopes.
68. Observatories are built in space because
(a) putting their instruments in space is good for the self-esteem of astronomers.
(b) they are much less expensive than ground-based observatories.
(c) they can last forever.
(d) to avoid atmospheric blurring.
69. One way to increase the resolving power of a reflecting telescope is to (a) replace its mirror with a larger one.
(b) replace its mirror with a smaller one.
(c) replace its mirror with a lens of the same diameter.
(d) observe objects using longer wavelengths.
70. One can calculate the distance to a nearby star based on its measured parallax. Stars with larger parallaxes are
(a) farther away.
(b) closer.
(c) the same distance as other stars.
(d) [There is no relation between stellar parallax and distance.]
71. Stars have dark lines in their spectra because
(a) they simply don’t emit light at certain wavelengths.
(b) magnetic fields in the Earth’s atmosphere absorb the radiation at some wave- lengths.
(c) the cooler atoms in their surface layers absorb the radiation at some wavelengths.
(d) [Stars don’t have dark lines in their spectra, only bright lines.]
72. A binary star is two stars that orbit around each other. By detecting this orbital motion, and using Kepler’s laws and the law of gravitation, one can directly measure the stars’
(a) temperatures.
(b) luminosities.
(c) masses.
(d) distances.
73. A spectroscopic binary is
(a) a single star that has two spectra.
(b) a single star with a single spectrum but each spectral line is split into two.
(c) a binary system that appears in telescopes as a single star but is recognized as two stars due to spectra that vary periodically in time.
(d) a binary system that appears in telescopes as a single star but is recognized as two stars when viewed in a stereo-spectroscope.
74. The Hertzsprung-Russell (H-R) diagram is a plot of stars’
(a) temperature vs. mass.
(b) mass vs. luminosity.
(c) luminosity vs. temperature.
(d) mass vs. diameter.
75. What is the main sequence?
(a) A region of cool, luminous stars in the upper right corner of the H-R diagram.
(b) A region of hot, dim stars in the lower left corner of the H-R diagram.
(c) An approximately straight line on the H-R diagram along which 90% of stars lies.
(d) The order in which spectral types are listed.
76. A cool but very luminous star has (a) a very large radius.
(b) a very small radius.
(c) a very small mass.
(d) a very low velocity.
77. A hot star that is not very luminous has (a) a very large radius.
(b) a very small radius.
(c) a very large mass.
(d) a very high velocity.
78. Cooler, less luminous main sequence stars have (a) relatively high masses.
(b) relatively low masses.
(c) similar masses to hotter main-sequence stars.
(d) masses that vary widely.
79. Red giants are found
(a) along the main sequence of the H-R diagram.
(b) in the upper-left part of the H-R diagram.
(c) in the upper-right part of the H-R diagram.
(d) in the lower-left part of the H-R diagram.
(e) in the lower-right part of the H-R diagram.
80. White dwarfs are found
(a) along the main sequence of the H-R diagram.
(b) in the upper-left part of the H-R diagram.
(c) in the upper-right part of the H-R diagram.
(d) in the lower-left part of the H-R diagram.
(e) in the central-right part of the H-R diagram.
81. Hot, bright main-sequence stars are found
(a) along the main sequence of the H-R diagram.
(b) in the upper-left part of the H-R diagram.
(c) in the upper-right part of the H-R diagram.
(d) in the lower-left part of the H-R diagram.
(e) in the lower-right part of the H-R diagram.
82. The Sun is found
(a) along the main sequence of the H-R diagram.
(b) in the upper-left part of the H-R diagram.
(c) in the upper-right part of the H-R diagram.
(d) in the lower-left part of the H-R diagram.
(e) in the lower-right part of the H-R diagram.
83. According to Eddington’s mass-luminosity relation, the more massive a main-sequence star is,
(a) the more luminous it is.
(b) the less luminous it is.
(c) [It could be more or less luminous, as it also depends on the star’s temperature.]
(d) [It could be more or less luminous, as it also depends on the star’s radius.]
84. The motion of a star can be determined by analyzing the star’s spectrum using (a) a heliocastronevescope.
(b) Wien’s law.
(c) the Stefan-Boltzmann law.
(d) the Stephen-Curry three-point effect.
(e) the Doppler effect.
85. The diameter of the Sun is about times as large as the diameter of the Earth.
(a) 10 (b) 100
(c) 1,000 (d) 10,000
86. The density of the Sun at its centre is its density at its surface.
(a) much greater than (b) much less than
(c) about the same as
(d) [The density at the centre is unknown, because we can’t access the Sun’s centre.]
87. The Sun is held together by
(a) electrostatic forces between ions in its interior.
(b) gas pressure.
(c) its gravitational force.
(d) [Nothing: the Sun is actually expanding very slowly.]
88. The Sun produces its energy primarily through (a) the fusion of neutrinos into helium.
(b) the fusion of positrons into hydrogen.
(c) the fusion of hydrogen into helium.
(d) electric currents generated in its core.
89. Most stars are born with approximately the following composition.
(a) About 50% hydrogen, about 50% helium, and less than 2% heavier elements.
(b) About 60% hydrogen, about 40% helium, and less than 2% heavier elements.
(c) About 75% hydrogen, about 25% helium, and less than 2% heavier elements.
(d) About 90% hydrogen, about 10% helium, and less than 2% heavier elements.
90. Since most stars are born with approximately the same composition, what character- istic most determines how their evolution will differ?
(a) The time at which they were formed.
(b) Their initial spectrum.
(c) Their initial mass.
(d) The location where they were formed.
91. The Sun’s photosphere is
(a) the Sun’s upper atmosphere.
(b) the Sun’s lower atmosphere.
(c) the Sun’s visible surface.
(d) the Sun’s hip night club.
92. The Sun’s chromosphere is
(a) the Sun’s upper atmosphere.
(b) the Sun’s lower atmosphere.
(c) the Sun’s visible surface.
(d) the Sun’s old-fashioned shiny hubcaps.
93. The Sun is supported against its own crushing weight by (a) its rapid rotation.
(b) magnetic forces.
(c) gravitational forces.
(d) gas pressure.
(e) gluinos.
94. “Ghostly” particles emitted by the Sun in vast numbers are called (a) ghostalinos.
(b) photinos.
(c) neutrinos.
(d) quarks.
95. Sunspots appear dark because
(a) they are made of different material than the surrounding gas.
(b) they are hotter than the surrounding gas.
(c) they are cooler than the surrounding gas.
(d) their magnetic fields block light.
96. Energy from the Sun’s core is transmitted to upper layers (up to a certain radius) primarily by
(a) radiation.
(b) conduction.
(c) convection.
(d) transvection.
97. Energy is transmitted upwards near the Sun’s surface primarily by (a) radiation.
(b) conduction.
(c) convection.
(d) transvection.
98. The Sun’s equator rotates (a) faster than near the poles.
(b) slower than near the poles.
(c) at the same rate as near the poles.
99. The internal balance of forces in the Sun is known as (a) supercalifragilisticexpialidocioustatic balance.
(b) hydrostatic balance.
(c) magnetohydrostatic balance.
(d) electromagnetostatic balance.
100. The solar wind
(a) occurs when the Sun has overeaten, especially spicy food.
(b) is usually followed by solar rain.
(c) occurs in explosive eruptions such as prominences and solar flares.
(d) is a steady, slight, and tenuous flow of mainly hydrogen and helium.