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Final Exam: December 2014 Number of pages: 18

Course: ASTR 1P01, Section 2 Number of students: 941 Examination date: 10 December 2014 Time limit: 2 hours Time of Examination: 12:00 – 14:00 Instructor: S. D’Agostino

Indicate the best response to each item on the scantron sheet provided.

No aids are permitted except for a non-programmable calculator.

Each question is worth 1 mark. Total number of marks: 100.

1. Stars are born in regions of space containing (a) interstellar birthing rooms.

(b) gigantic stork-like intergalactic structures.

(c) branch plants of ProtoStar Inc.

(d) enormous clouds of gas and dust.

2. It takes light approximately 1.3 to go from Earth to Moon.

(a) seconds.

(b) minutes.

(c) hours.

(d) light years.

3. The distance between the Earth and the Sun is approximately (a) 150 light-minutes.

(b) 150 million km.

(c) 150 billion km.

(d) 150 light-years.

4. The speed of light is approximately (a) 300 km/h.

(b) 300,000 km/h.

(c) 300 km/s.

(d) 300,000 km/s.

5. The Milky Way galaxy is shaped approximately like (a) a cigar with a spherical halo.

(b) a cone with a spherical halo.

(c) a disk with a spherical halo.

(d) an egg with a spherical halo.

6. The Milky Way galaxy is part of a galaxy cluster.

(a) super-wealthy (b) rich

(c) middle-class (d) poor

7. Superclusters of galaxies are linked to form (a) huge honeycomb-like structures.

(b) distinctive diamond-like structures.

(c) long filament-like structures.

(d) supercluster fudge-like sticks of toffee-like Facebook likes.

8. The diameter of the Milky Way galaxy is about (a) 100,000 kilometres

(b) 100,000 astronomical units.

(c) 100,000 interstellar units.

(d) 100,000 light years.

9. A constellation is a group of stars that lie in (a) approximately the same location in space.

(b) approximately the same direction as viewed from Earth.

(c) an open cluster.

(d) a closed cluster.

10. The part of the night sky that you can observe throughout a particular night of the year depends on your

(a) attitude.

(b) latitude.

(c) longitude.

(d) neighbour dude.

11. The centre of the celestial sphere is (a) at the zenith.

(b) at the Earth-Moon epicentre.

(c) at the Earth’s centre.

(d) collinear with the centres of the celestial cone and the celestial cylinder.

12. As observed from above the Earth’s north pole, the Earth rotates , which means that the stars appear to move .

(a) from west to east / from east to west (b) from east to west / from west to east

(c) from north to south / from south to north (d) from south to north / from north to south

13. For stars that rise and set, each such star rises approximately each day.

(a) 4 minutes earlier (b) 4 minutes later

(c) 50 minutes earlier (d) 50 minutes later 14. We have seasons because

(a) Earth’s orbit is elliptical, and so we are a little closer to the Sun in the summer and a little farther from the Sun in the winter.

(b) Earth’s orbit is tilted relative to the galactic plane, so we are a little closer to the Sun in the summer and a little farther from the Sun in the winter.

(c) Earth’s rotation axis is tilted relative to the plane of Earth’s orbit around the Sun.

(d) Earth’s rotation axis precesses.

15. During the time of the year after the winter solstice and before the summer solstice, the Sun rises a little farther each day.

(a) north (b) south (c) east (d) west

16. The Sun is visible for 24 hours per day north of the Arctic circle (a) on the summer solstice.

(b) on the winter solstice.

(c) on the vernal equinox.

(d) on the autumnal equinox.

17. The full moon rises (a) at sunrise.

(b) at sunset.

(c) near the middle of the day.

(d) near the middle of the night.

18. The new moon rises (a) at sunrise.

(b) at sunset.

(c) near the middle of the day.

(d) near the middle of the night.

19. The first-quarter moon rises (a) at sunrise.

(b) at sunset.

(c) near the middle of the day.

(d) near the middle of the night.

20. The third-quarter moon rises (a) at sunrise.

(b) at sunset.

(c) near the middle of the day.

(d) near the middle of the night.

21. The line of nodes shifts by about 20

each year, and it takes the Earth about 20 days to move through the same angle. This means that

(a) dates for solstices and equinoxes shift by about 20 days per year.

(b) dates for the line of antinodes shifts by about 20 days per year.

(c) dates for eclipses shift by about 20 days per year.

(d) dates for the release of new Stephenie Meyer novels shifts by about 20 days per year.

22. The Moon appears red during a total lunar eclipse because

(a) giant lasers from Niagara Falls illuminate the Moon for the benefit of tourists.

(b) sunlight is redshifted at a greater rate during lunar eclipses.

(c) reflected light from the Moon is blueshifted away from the Earth but redshifted towards the Earth.

(d) sunlight from the red end of the spectrum is refracted by Earth’s atmosphere.

23. In the year 1079, the Persian poet, mathematician, and astronomer Omar Khayyam determined with surprising accuracy.

(a) the distance between the Earth and the Moon (b) the distance between the Earth and the Sun

(c) the time needed for the Moon to orbit the Earth (d) the length of the tropical year

24. The most influential ancient Greek natural philosopher was (a) Aristotle.

(b) Ari Gold.

(c) Jeremias of Piven.

(d) Giannis Antetokounmpo.

25. Ancient Greek thinkers argued that the Earth must be spherical because (a) as you travel west, your longitude changes by 15

per hour.

(b) those who live further north don’t rotate as far as the Earth spins.

(c) as you travel south, you begin to see stars that were previously below the horizon.

(d) if Earth were flat all the water in oceans would pour off the edges.

26. Ancient Greek astronomers observed that during lunar eclipses, Earth always casts a circular shadow on the Moon. This is evidence for

(a) the Earth and Moon being approximately the same angular size.

(b) the existence of the line of nodes.

(c) the Earth being spherical.

(d) the Sun being spherical.

27. The ancient Greek thinker used observations and reasoning to argue that the Sun is much larger than the Moon and much farther from Earth than the Moon.

(a) Aristotle (b) Aristarchus

(c) Atticus Finch

(d) Lemony Snicket

28. At the time of Galileo and Kepler, which of the following observations was the strongest evidence for a heliocentric model of the solar system?

(a) The moons of Jupiter.

(b) Stellar parallax.

(c) The sunspots.

(d) The gibbous and the quarter phases of Venus.

29. The ancient Greek astronomer who first determined the size of the Earth was (a) Eratosthenes of Cyrene.

(b) Hipparchus of Nicaea.

(c) Ptolemy of Alexandria.

(d) Dude of Lebowski.

30. An advantage of the Renaissance heliocentric model of the solar system (over the geocentric model) is that

(a) stellar parallax is easier to measure.

(b) apparent retrograde motions of planets is easier to explain.

(c) the apparent motion of the Sun through the zodiac is easier to explain.

(d) the times of eclipses can be predicted more accurately.

31. Copernicus’s great advance was to reintroduce the model of the solar system, which allowed him to determine the relative distances of the planets from the Sun.

(a) heliocentric (b) geocentric

(c) celestial sphere (d) epicycle

32. Tycho Brahe’s great advance was to

(a) mathematically analyze observations made by Kepler to prove that the orbit of Mars is elliptical.

(b) make the first observations of comets.

(c) make the most accurate astronomical observations up to that time.

(d) win the astronomical horse race of 1566 by a nose.

33. The mass of a planet can be determined by measuring the orbital radius and period of one of its satellites, and then using

(a) Kepler’s first law of planetary motion.

(b) Kepler’s second law of planetary motion.

(c) Kepler’s third law of planetary motion.

(d) Kepler’s fourth law of planetary motion.

34. mathematically deduced Kepler’s laws of planetary motion using Newton’s laws of motion and Newton’s law of gravity.

(a) Roger Bacon.

(b) Galileo Galilei.

(c) Robert Hooke.

(d) Johannes Kepler.

(e) Isaac Newton.

35. Kepler’s first law of planetary motion concerns

(a) the variation in the speed of a planet as it orbits the Sun.

(b) the relation between the distance of a planet from the Sun and the shape of its orbit.

(c) the relation between the distance of a planet from the Sun and its period.

(d) the shape of planetary orbits.

36. According to Newton’s laws of motion, an object moving in a circle at a constant speed is subject to a force pointing

(a) along its trajectory (that is, tangent to its path).

(b) toward the centre of the circle.

(c) away from the centre of the circle.

(d) [There is no force on the object, because it moves at a constant speed.]

37. Light is an electromagnetic wave.

(a) True.

(b) False.

38. White light from the Sun

(a) has a wavelength close to the centre of the visible part of the spectrum.

(b) has a wavelength close to the ultraviolet end of the visible part of the spectrum.

(c) has a wavelength close to the infrared end of the visible part of the spectrum.

(d) is a mixture of all wavelengths of light.

39. Earth’s atmosphere wavelengths of the electgromagnetic spectrum.

(a) is transparent to all (b) is transparent to some

(c) is reductive to some (d) acts as a greenhouse to all 40. Electromagnetic radiation

(a) propagates through space as waves.

(b) interacts with matter as waves.

41. Electromagnetic radiation

(a) propagates through space as particles.

(b) interacts with matter as particles.

42. For electromagnetic radiation, the shorter the wavelength (a) the smaller the photon energy.

(b) the larger the photon energy.

(c) [Photons don’t have wavelengths.]

43. Refraction of light refers to

(a) the fracturing of glass lenses when light that is too intense passes through them.

(b) the separation of light into its various fractional elements for data analysis.

(c) light bending as it passes through a lens.

(d) repeated reflection by mirrors that are aligned in a nearly parallel array.

44. The speed of light is

(a) larger in glass than in air.

(b) smaller in glass than in air.

(c) the same in both glass and air.

(d) [It depends on the crystalline structure of the glass.]

45. The most important property of a telescope is its (a) light-gathering power.

(b) magnifying power.

(c) resolving power.

(d) refraction/reflection ratio (RRR).

(e) diffractivity.

46. The light-gathering power of a telescope is

(a) proportional to the distance between the objective and the eyepiece.

(b) proportional to the focal length of the objective.

(c) proportional to the focal length of the eyepiece.

(d) proportional to the cross-sectional area of the objective.

(e) proportional to the cross-sectional area of the armature.

47. The resolving power of a telescope is

(a) proportional to the distance between the objective and the eyepiece.

(b) proportional to the focal length of the objective.

(c) proportional to the focal length of the eyepiece.

(d) proportional to the diameter of the objective.

(e) proportional to the diameter of the armature.

48. The magnifying power of a telescope is equal to

(a) the ratio of the focal length of the objective to the focal length of the eyepiece.

(b) the ratio of the diameter of the objective to the diameter of the eyepiece.

(c) the ratio of the cross-sectional area of the objective to the cross-sectional area of the eyepiece.

(d) the ratio of the objective-viewer distance to the eyepiece-viewer distance.

49. Most large optical telescopes are reflectors because

(a) reflectors are more in keeping with astronomical traditions.

(b) the guild of reflecting telescope makers is larger and more powerful than the guild of refracting telescope makers.

(c) it’s easier and cheaper for glass-blowers to produce mirrors than lenses.

(d) there are too many problems with refractors, so large reflectors are better than

large refractors.

50. To avoid atmospheric blurring, most ground-based optical telescopes are located (a) in forested areas, where the moisture in the air aids the refraction of light.

(b) deep in valleys, where the Sun’s light can’t disturb the operation of the telescope.

(c) on mountains in areas of the Earth where the climate is dry and the skies are frequently clear.

(d) near beaches, because most astronomers love surfing.

51. Stellar parallax is a good method for determining the distances to (a) all stars.

(b) stars that are not very far away.

(c) stars that are at a medium distance.

(d) stars that are very far away.

52. The luminosity of a star is its (a) brightness per unit distance.

(b) power output per unit wavelength.

(c) energy output per unit time.

(d) force output per unit photon.

53. Stars X and Y have the same apparent brightness. Star X is 5 times farther from Earth than Star Y. The luminosity of Star X is the luminosity of Star Y.

(a) 1/5th of (b) 1/25th of

(c) 5 times (d) 25 times

54. Continuous spectra are produced by (a) only gases.

(b) only solids.

(c) solids or low-density gases.

(d) solids or high-density gases.

55. We can learn a lot about a star from its spectrum. All of the following statements are true except one. Which one is false?

(a) Doppler shifts of a star’s spectral lines determine the star’s speed towards or away from us.

(b) Chemical elements present in the star can be identified by recognizing patterns of spectral lines that correspond to particular elements.

(c) The peak of a star’s thermal emission tells us its temperature. Hotter stars peak at shorter wavelengths.

(d) The total amount of light in a star’s spectrum tells us its radius.

56. When white light passes through a cool gas, we see (a) an absorption line spectrum.

(b) an emission line spectrum.

(c) a spectrum that depends on the wavelength of the white light.

(d) a spectrum that depends on the speed of the white light.

57. Wien’s law is typically used in astronomy to

(a) determine the wavelength of maximum emission of a star.

(b) determine a star’s density.

(c) determine a star’s chemical composition.

(d) determine the temperature of a star.

58. Stars that are luminous and cool (a) are very small.

(b) are very large.

(c) are neither very large nor very small.

(d) might be large or small, depending on other factors.

59. Stars that are not very luminous and hot (a) are very small.

(b) are very large.

(c) are neither very large nor very small.

(d) might be large or small, depending on other factors.

60. An electron bound to an atom

(a) can have only certain energies, which depend on the electron.

(b) can have any energies within a certain range, which depends on the atom.

(c) can have any energies within a certain range, which depends on the electron.

(d) can have only certain energies, which depend on the atom.

61. For main-sequence stars, Eddington’s relation states that

(a) the larger the peak wavelength of a star, the larger is its luminosity.

(b) the larger the density of a star, the larger is its luminosity.

(c) the larger the temperature of a star, the larger is its luminosity.

(d) the larger the mass of a star, the larger is its luminosity.

62. The more massive a main-sequence star is, the is its lifetime.

(a) longer.

(b) shorter.

63. Protons and neutrons in an atomic nucleus are held together by (a) electromagnetic forces.

(b) strong nuclear forces.

(c) weak nuclear forces.

(d) gravitational forces.

64. The stars with the highest surface temperatures are (a) red.

(b) yellow.

(c) white.

(d) blue.

65. Which of the following types of radiation from outer space cannot be detected in a ground-based observatory?

(a) Ultraviolet.

(b) Visible light.

(c) X-ray.

(d) Radio.

66. The radius of a star can be determined from its (a) luminosity and distance.

(b) luminosity and surface temperature.

(c) surface temperature and distance.

(d) [None of the others.]

67. Some stars “twinkle” because

(a) our eyes cannot focus on distant objects.

(b) they are about to run out of fuel.

(c) their luminosity changes in time.

(d) of atmospheric blurring.

68. Using spectroscopic parallax enables one to determine a star’s (a) spectral class.

(b) luminosity class.

(c) distance (using its parallax angle).

(d) distance (using the H-R diagram).

69. Which term describes a pair of stars that we can determine are orbiting each other only by measuring their periodic Doppler shifts?

(a) Spectroscopic binary.

(b) Visual binary.

(c) Eclipsing binary.

(d) Double star.

70. The most abundant chemical element in a main-sequence star is (a) Oxygen (O).

(b) Hydrogen (H).

(c) Carbon (C).

(d) Helium (He).

71. 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.

72. 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.

73. Binary star systems are important because they are used to determine (a) spectral classes of stars.

(b) distances to stars.

(c) luminosity classes of stars.

(d) masses of stars.

74. The farther away a star is, the smaller is its parallax angle.

(a) True.

(b) False.

75. Stars that are moving away from Earth produce spectra that are as observed on Earth.

(a) redshifted (b) blueshifted

(c) greenshifted (d) whiteshifted

76. Main-sequence stars that have low mass are (a) dim and hot.

(b) dim and cool.

(c) bright and hot.

(d) bright and cool.

77. On a Hertzsprung-Russell diagram, red giant stars are found towards the (a) upper right.

(b) lower right.

(c) upper left.

(d) lower left.

78. On a Hertzsprung-Russell diagram, white dwarf stars are found towards the (a) upper right.

(b) lower right.

(c) upper left.

(d) lower left.

79. On a Hertzsprung-Russell diagram, main-sequence stars that have the largest mass are found towards the

(a) upper right.

(b) lower right.

(c) upper left.

(d) lower left.

80. On a Hertzsprung-Russell diagram, stars that have the largest radii are found towards the

(a) upper right.

(b) lower right.

(c) upper left.

(d) lower left.

81. On a Hertzsprung-Russell diagram, stars that are cool and dim are found towards the (a) upper right.

(b) lower right.

(c) upper left.

(d) lower left.

82. On a Hertzsprung-Russell diagram, stars that are cool and luminous are found towards the

(a) upper right.

(b) lower right.

(c) upper left.

(d) lower left.

83. 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.

84. 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.

85. The Sun’s corona is

(a) the Sun’s upper atmosphere.

(b) the Sun’s lower atmosphere.

(c) the Sun’s visible surface.

(d) the Sun’s favourite beer.

86. Which part of the Sun is hottest?

(a) Photosphere.

(b) Chromosphere.

(c) Corona.

(d) Aurora.

87. The thinnest layer of the Sun is the (a) corona.

(b) chromosphere.

(c) photosphere.

(d) radiative layer.

(e) convection layer.

88. The diameter of the Sun is about times the Earth’s diameter.

(a) 10 (b) 100

(c) 1,000 (d) 1,000,000

89. The Sun’s mass is about times the Earth’s mass.

(a) 300 (b) 3,000

(c) 30,000 (d) 300,000

90. The main source of energy production in the Sun is (a) nuclear fission.

(b) nuclear fusion.

(c) conversion of gravitational potential energy into thermal energy.

(d) dynamo processes in the Sun’s magnetic field.

91. The high pressure in the Sun’s interior is a result of the core’s (a) high density of neutrinos.

(b) high rate of chemical reactions.

(c) high magnetic field (d) high temperature.

92. “Ghostly” particles emitted by the Sun in vast numbers are called (a) ghostalinos.

(b) photinos.

(c) neutrinos.

(d) quarks.

93. The Sun is in a state of

(a) electromagnetic equilibrium.

(b) hydrostatic equilibrium.

(c) jalapenoic equilibrium.

(d) nucleodynamic equilibrium.

94. About years elapse between times of maximum solar activity.

(a) 11 (b) 22

(c) 2,000 (d) 4.6 billion

95. Sunspots appear dark because

(a) they are not hot enough to emit any visible light.

(b) they are holes in the solar surface through which we can see to deeper, darker layers of the Sun.

(c) they are fairly bright but appear dark against the even brighter background of the surrounding surface.

(d) they emit light in wavelengths that we can’t see with the naked eye.

96. Energy is transported from the Sun’s core to its surface mainly by (a) conduction and convection.

(b) radiation and convection.

(c) radiation and conduction.

(d) nuclear decay processes.

97. Solar wind consists primarily of streaming away from the Sun.

(a) hot, dry air

(b) magnetic monopoles (c) Bohr magnetons (d) charged particles

98. We know that the Sun’s energy does not result from a chemical burning process because (a) its luminosity would be much larger.

(b) the Sun would have exhausted its fuel long ago.

(c) there would be more carbon in its atmosphere.

(d) of the greenhouse effect.

99. The Sun’s temperature fluctuates regularly over short time scales, but over long time scales it is

(a) very gradually decreasing.

(b) constant.

(c) very gradually increasing.

100. The magnetic field within a sunspot is typically than the Sun’s average magnetic field.

(a) 1000 times stronger (b) 10 times stronger

(c) 10 times weaker

(d) 1000 times weaker