Download Return both exam and scantron sheet when you

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BROCK UNIVERSITY
Number of pages: 17
Number of Students: 400
Number of hours: 2
Instructor: B.Mitrović
Final Exam April 2015
Course: ASTR 1P02
Date of Examination: April 20, 2015
Time of Examination: 9:00–11:00
No examination aids other than those specified on this examination script are permitted (FHB
III: 9.1.2.B). Use or possession of unauthorized materials will automatically result in the award
of a zero grade for this examination.
PLEASE RECORD YOUR STUDENT NAME AND NUMBER ON THE SCANTRON SHEET BEFORE YOU DO ANYTHING; USE AN HB PENCIL ON THE
SCANTRON SHEET. THERE ARE 100 QUESTIONS.
Return both exam and scantron sheet when you leave
the gym
1. A dark nebula emits energy mostly in the form of
(a) gamma-ray radiation.
(b) X-ray radiation.
(c) UV radiation
(d) infrared radiation.
2. A nebula which produces light by fluorescence is called
(a) reflection
(b) planetary
(c) emission
(d) [None of the above.]
3. Which property of a star determines the temperature of its core?
(a) Surface temperature.
(b) Luminosity.
(c) Mass.
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nebula.
Course: ASTR1P02
Date: April 20, 2015
page 2 of 17 pages
4. The spin rate of a pulsar
(a) increases over time.
(b) decreases over time.
(c) does not change in time.
5. The wavelength of a source of light approaching the event horizon of a black hole is
(a) blueshifted.
(b) redshifted.
(c) unchanged.
6. Which one of these stars spends most time in the protostar stage?
(a) 10 solar mass star.
(b) 5 solar mass star.
(c) 1 solar mass star.
(d) 0.5 solar mass star.
7. The stronger is the force of gravity on a clock, the faster it runs.
(a) True.
(b) False.
8. A protostar with mass 0.2 solar mass will become
(a) a red dwarf.
(b) a brown dwarf.
9. The helium burning into carbon in the core of a medium mass star proceeds via
(a) proton-proton chain.
(b) CNO-cycle.
(c) triple alpha-process.
10. If the mass of an object composed of degenerate material increases, its radius decreases.
(a) True.
(b) False.
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11. Once the hydrogen in the Sun’s core is fused into helium, further fusion of hydrogen into
helium will go on in
(a) the photosphere.
(b) a shell surrounding the helium core.
(c) the convection zone.
12. Planetary nebula is
(a) a supernova remnant.
(b) a nebula in which planets form around a star.
(c) a glowing shell of material ejected by a dying medium-mass star.
(d) [None of the above.]
13. Which of these white dwarfs has larger radius?
(a) Half a solar mass white dwarf.
(b) One solar mass white dwarf.
14. The gravitational collapse of a high-density white dwarf is prevented by
(a) the rapid spin of a white dwarf.
(b) thermal pressure created by carbon nuclei.
(c) the pressure created by degenerate carbon nuclei
(d) the pressure created by degenerate electrons.
15. The density of a white dwarf is about
(a) 1011 kilograms per centimeter cubed (i.e., equal to the typical density of an atomic
nucleus).
(b) 1000 kilograms per centimeter cubed.
(c) 10 grams per centimeter cubed (i.e., equal to typical metallic density).
(d) 1 gram per centimeter cubed (i.e., equal to the density of water).
16. There are hydrogen spectral lines in the spectrum of Type Ia supernova.
(a) True.
(b) False.
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Course: ASTR1P02
Date: April 20, 2015
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17. The luminosity of quasar X varies with a period of one day and the luminosity of quasar
Y varies with the period of one week. Which quasar has the smaller active region?
(a) Quasar X.
(b) Quasar Y.
(c) [No conclusion can be made.]
18. White dwarfs will stop emitting light in a distant future.
(a) True.
(b) False.
19. Chandrasekhar’s limit is
(a) the maximum radius of a red giant.
(b) the radius within which an object must shrink to become a black hole.
(c) the maximum mass of a body composed of degenerate matter.
(d) the minimum mass of a body composed of degenerate matter.
20. The maximum mass that a white dwarf can have is
(a) 0.14 solar masses.
(b) 1.4 solar masses.
(c) 14 solar masses.
(d) [The statement is wrong. A white dwarf can have any mass.]
21. Which of the following nuclei has the highest binding energy per nucleon?
(a) The nucleus of carbon.
(b) The nucleus of iron.
(c) The nucleus of gold.
22. A main sequence star maintains its hydrostatic equilibrium by
(a) electron degeneracy pressure.
(b) neutron degeneracy pressure.
(c) pressure-temperature thermostat.
(d) energetic neutrinos produced in its core.
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23. Type II supernovae are important because
(a) all of a star’s hydrogen is returned to the interstellar medium.
(b) the elements heavier than iron are synthesized.
(c) the resulting burst of neutrinos keeps the galaxy from collapsing.
(d) they produce helium from hydrogen.
24. The current luminosity of the Sun is
(a) smaller than when it was formed 4.6 billion years ago.
(b) the same as when it was formed 4.6 billion years ago.
(c) larger than when it was formed 4.6 billion years ago.
(d) [No statement can be made.]
25. Which of these stars spends the longest time as a main sequence star?
(a) 0.5 solar mass star.
(b) 1 solar mass star.
(c) 15 solar mass star.
(d) [No statement can be made.]
26. The pressure of degenerate electrons increases with temperature.
(a) True.
(b) False.
27. Which of these fusion reactions in a high-mass star creates most energy per nuclear
reaction?
(a) The fusion of hydrogen into helium.
(b) The fusion of helium into carbon.
(c) The fusion of silicon into iron.
(d) [No statement can be made.]
28. A star of 5 solar mass fuses hydrogen into helium via
(a) proton-proton chain.
(b) triple alpha process.
(c) CNO cycle.
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29. The center of our galaxy is in the direction of constellation
(a) Gemini.
(b) Pisces.
(c) Sagittarius.
(d) Virgo.
30. How long does it take the radio waves produced by Sagittarius A∗ (or Sgr A∗ ) at the
center of the Milky Way to reach us on Earth?
(a) 300 years.
(b) 3,000 years.
(c) 30,000 years.
(d) 300,000 years.
31. Cepheid variable A has the period of luminosity variation one-half that of Cepheid
variable B.
(a) The peak luminosity of A is smaller than the peak luminosity of B.
(b) The peak luminosity of A is larger than the peak luminosity of B.
(c) [No conclusion can be made.]
32. Harlow Shapley used
to measure the distances in the Milky Way.
(a) spectroscopic parallax
(b) the Doppler shift of starlight
(c) stellar parallax
(d) Cepheid variables
33. The spiral arms of a galaxy move slower than its stars.
(a) True.
(b) False.
34. The oldest stars in the Milky Way are found mostly in
(a) the halo.
(b) the bulge.
(c) the disk.
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35. The halo stars of the Milky Way are mostly
(a) Population II stars.
(b) Population III stars.
(c) [None of the above.]
36. The redshift of light emitted by the distant galaxies is caused by
(a) the gravitational redshift.
(b) the cosmological redshift.
(c) the Doppler effect.
(d) [None of the above.]
37. Which stars contain the highest amounts of elements heavier than helium?
(a) Population II stars.
(b) Population III stars.
(c) [None of the above.]
38. Astronomers observe that the galaxies in clusters move faster than expected on the basis
of the material visible in them. From this they infer the presence of
in the
Universe.
(a) dark energy
(b) dark matter
(c) super-massive black holes
39. Which distance indicators are used to determine the distances of the most distant galaxies in the Universe?
(a) Cepheids.
(b) Globular clusters.
(c) Type Ia supernovae.
40. As a black hole passes between us and a star the star’s brightness
of gravitational microlensing.
(a) increases.
(b) decreases.
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as a result
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Date: April 20, 2015
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41. The orbits of Halo stars are
(a) circular.
(b) parabolic.
(c) hyperbolic.
(d) highly elliptical.
42. If you lived in a galaxy far away from the Local Group, your redshift measurements
would show that galaxies move
(a) away from you in the same way as observed from the Milky Way.
(b) away from the Milky Way but toward you.
(c) toward you out to the distance of the Milky way; away at larger distances.
(d) toward you in half the sky, away in the other half.
43. Which of these galaxies are the least luminous?
(a) Elliptical.
(b) Spiral.
(c) Irregular.
44. The concept of dark energy is introduced to explain
(a) high speed with which galaxies in a cluster orbit each other.
(b) the microwave background radiation.
(c) high speed of stars near the edges of spiral galaxies.
(d) [None of the above.]
45. Which of these galaxies has the smallest central bulge?
(a) Sa.
(b) Sb.
(c) Sc.
46. Elliptical galaxies consist mostly of
(a) Population II stars.
(b) Population III stars.
(c) [None of the above.]
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47. The cosmological redshift is caused by
(a) gravity.
(b) expansion of space.
(c) light passing through gas and dust.
(d) Doppler effect.
48. Astronomers have determined the mass of the supermassive black hole at the center of
the Milky Way by
(a) measuring its Schwarzschild radius RS against background stars and then using
RS = 3M to determine its mass M.
(b) measuring orbital data (distance and speed) of stars orbiting it.
(c) measuring its energy output in the form of X-rays.
(d) [There is no supermassive black hole at the center of our galaxy.]
49. The distance of galaxy A is greater than the distance of galaxy B. Which galaxy has a
greater redshift?
(a) Galaxy A.
(b) Galaxy B.
50. The microwave cosmic background radiation obeys the Wien’s (blackbody radiation)
law.
(a) True.
(b) False.
51. If Ω, which is the ratio of the mass/energy density in the Universe to its critical value,
was greater than 1 then the global curvature of the Universe would be
(a) positive.
(b) negative.
(c) zero.
52. The light emitted by a source approaching the event horizon of a black hole is redshifted
because of
(a) the cosmological redshift.
(b) the Doppler effect.
(c) the gravitational redshift.
(d) [None of the above.]
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53. If Ω, which is the ratio of the mass/energy density in the Universe to its critical value,
was less than 1 then the Universe would be
(a) open.
(b) closed.
(c) flat.
(d) [None of the above.]
54. Population I stars are
(a) dim and cool.
(b) 10 billion years old.
(c) metal poor.
(d) metal rich.
55. Which of the following statements about the cosmic background radiation is not true?
(a) It had much higher temperature in the past.
(b) It has a temperature of about 3 degrees K above absolute zero.
(c) It’s wavelength is shorter than the wavelength of visible light.
(d) It appears essentially the same in all directions (it is isotropic).
56. Based on the Hubble’s law the estimated age of the Universe is
the current value of Hubble’s constant.
(a) H0
(b) H02
(c) 1/H0
(d) 1/H02
57. Elliptical galaxies contain a lot of gas and dust.
(a) True.
(b) False.
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, where H0 is
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Date: April 20, 2015
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58. The galaxies with active galactic nuclei represent
(a) about a half of the observed galaxies in the Universe.
(b) a small percentage of the observed galaxies in the Universe.
(c) the majority of the observed galaxies in the Universe.
59. Astronomers can observe a MACHO using
(a) X-ray detectors.
(b) gamma-ray detectors.
(c) neutrino detectors.
(d) gravitational microlensing technique.
60. Which of these planets has the shortest year (orbital period)?
(a) Mercury.
(b) Venus.
(c) Earth.
(d) Mars.
61. The mass of the Sun is
of the mass of the entire Solar System.
(a) about 10%
(b) about 50%
(c) about 75%
(d) over 99%
62. Which of these planets has the largest mass?
(a) Jupiter.
(b) Saturn.
(c) Uranus.
(d) Neptune.
63. Planet Mars has no moons (satellites).
(a) True.
(b) False.
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64. Jovian planets have larger densities than the terrestrial planets.
(a) True.
(b) False.
65. Uranus spins counterclockwise as observed from far above the Earth’s North Pole.
(a) True.
(b) False.
66. The diameter of the Sun is about
times larger than the diameter of the Earth.
(a) 10
(b) 100
(c) 1,000
(d) 10,000
67. Apollo asteroids have circular orbits.
(a) True.
(b) False.
68. Why is Pluto no longer considered to be a planet?
(a) Because it is smaller than any of the 8 planets.
(b) Because it does not have a roughly spherical shape.
(c) Because it has not cleared its orbit from other bodies at approximately the same
distance.
69. Which of these substances could condense and form solid particles at a distance less
than 5 AU (Astronomical Units) from the protosun?
(a) Water (H2 O).
(b) Ammonia (NH3 ).
(c) Metallic compounds.
(d) Methane (CH4 ).
70. Which of these planets has the highest reflectivity?
(a) Mercury.
(b) Venus.
(c) Earth.
(d) Mars.
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71. Which of these planets has the hottest surface?
(a) Mars.
(b) Earth.
(c) Venus.
(d) Mercury.
72. The tidal force on the Moon exerted by the Earth is greater than the tidal force on the
Earth exerted by the Moon.
(a) True.
(b) False.
73. Which of these planets has the highest atmospheric pressure at the Surface?
(a) Mercury.
(b) Venus.
(c) Earth.
(d) Mars.
74. Planet Mars does not have planetwide magnetic field.
(a) True.
(b) False.
75. The greenhouse gases trap ultraviolet (UV) radiation.
(a) True.
(b) False.
76. Smaller planets lose the internal heat faster than the larger ones because they have
(a) smaller surface to volume ratio.
(b) larger surface to volume ratio.
(c) smaller mass.
(d) lower density.
77. The impact craters have floors that are lower than the surrounding surface.
(a) True.
(b) False.
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78. The atmosphere of Mars consists mostly of
(a) methane.
(b) nitrogen.
(c) ammonia.
(d) carbon dioxide.
79. The atmosphere of Earth consists mostly of
(a) methane.
(b) nitrogen.
(c) ammonia.
(d) carbon dioxide.
80. The atmosphere of planet Jupiter is mostly
(a) helium.
(b) ammonia.
(c) hydrogen.
(d) methane.
81. What causes the Cassini division in the rings of Saturn?
(a) The tidal force exerted by satellite Mimas.
(b) The orbital resonance with satellite Mimas.
(c) The tidal force exerted by Jupiter.
(d) The orbital resonance with Jupiter.
82. When a piece of rock formed it consisted of radioactive isotope A. After four half-life of
A the percentage of A in the rock is
(a) 50 %.
(b) 25 %.
(c) 12.5 %.
(d) 6.25 %.
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83. Which of these planets has no impact craters?
(a) Mercury.
(b) Venus.
(c) Earth.
(d) Mars.
(e) Jupiter.
84. Which of the following Galilean satellites has active volcanoes?
(a) Io.
(b) Europa.
(c) Ganymede.
(d) Callisto.
85. What causes the Kirkwood gaps in the asteroid belt?
(a) The tidal force exerted by Jupiter.
(b) The orbital resonance with Jupiter.
(c) The tidal force exerted by Mars.
(d) The orbital resonance with Mars.
86. What was the initial source of oxygen in the Earth’s atmosphere?
(a) The primary atmosphere.
(b) Photosynthesis by cyanobacteria.
(c) Dissociation of water molecules by infrared radiation.
(d) Dissociation of water molecules by UV-radiation from the Sun.
87. The asteroids in the asteroid belt have retrograde (clockwise) orbital motion as seen
from far above the Earth’s North Pole.
(a) True.
(b) False.
88. Which of these seismic waves cannot propagate through a liquid?
(a) S (or shearing) waves.
(b) P (or pressure) waves.
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89. Which is the largest asteroid (now classified as a dwarf planet)?
(a) Ceres.
(b) Pallas.
(c) Juno.
(d) Vesta.
90. Which part of a comet’s tail is curved.
(a) Ion tail.
(b) Dust tail.
91. A small body which burns as it passes through the Earth’s atmosphere is called
(a) meteoroid.
(b) meteor.
(c) meteorite.
92. Which of these asteroids are located near the outer edge of the asteroid belt?
(a) C-asteroids.
(b) M-asteroids.
(c) S-asteroids.
93. We can observe more meteors before the midnight than after the midnight.
(a) True.
(b) False.
94. Which of these represent the smallest group of meteorites?
(a) Irons.
(b) Stony-irons.
(c) Carbonaceous.
(d) Stones.
95. Most active volcanoes on Earth are located at the boundaries of tectonic plates.
(a) True.
(b) False.
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96. The length of Earth’s day is
(a) decreasing over time.
(b) increasing over time.
(c) does not change with time.
97. Which of these asteroids have the lowest reflectivity (albedo)?
(a) M-asteroids.
(b) C-asteroids.
(c) S-asteroids.
98. The Roche limit is
(a) the maximum mass of a satellite.
(b) the maximum distance of a satellite.
(c) the minimum radius of a planetary ring.
(d) [None of the Above.]
99. All Galilean satellites of Jupiter have sinchronous rotation.
(a) True.
(b) False.
100. The age of almost all meteorites is about
(a) 2.5 billion years.
(b) 3.5 billion years.
(c) 4.5 billion years.
(d) 5.5 billion years.
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