Astronomy Final 2

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Astronomy Final 2
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2012-05-18 19:30:10
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  1. The diagram below illustrates a light source, a gas cloud, and three different lines of sight. Along which line of sight would an observer see an absorption spectrum?
    c. 3
  2. An atom can be excited
    • b. if it collides with another atom or electron.
    • c. if it absorbs a photon.
  3. Sunspots
    a. are cooler than their surroundings.
  4. Granulation is caused by
    b. rising gas below the photosphere
  5. The chromosphere of the sun
    a. is hotter than the photosphere.
  6. The centers of granules
    a. are hot material rising to the photosphere from below.
  7. We know that giant stars are larger in diameter than the sun because
    a. they are more luminous but have about the same temperature.
  8. A recent sunspot maximum occurred in 2001, what is the year of the sunspot maximum that immediately follows the 2001 maximum if the solar cycle continues?
    b. 2012
  9. Which of the following types of electromagnetic radiation has the greatest energy?
    d. gamma-rays
  10. Which of the following types of electromagnetic radiation has the lowest energy?
    e. infrared radiation
  11. When we say that gravitation is universal we mean that
    e. it is a property of all matter.
  12. The force due to gravity between two objects depends on
    • I. the mass of each object.
    • III. the distance between the two objects.
  13. Radio telescopes have poor resolving power because
    c. radio waves have long wavelengths.
  14. The __________ of an object is a measure of the amount of matter it contains. On the other hand __________ is a measure of the gravitational force on an object.
    b. mass weight
  15. Blue light
    a. has a greater energy than red light.
  16. The Copernican system was no more accurate than the Ptolemaic system in predicting the positions of the planets because
    c. the Copernican system included uniform circular motion.
  17. Which of the following types of electromagnetic radiation has the highest frequency?
    d. gamma-rays
  18. Galileo's telescopic discoveries of mountains on the moon and spots on the sun were controversial because they suggested that the sun and moon
    b. were not perfect spheres
  19. A(n) __________ is a circle whose center is located on the circumference of another circle.
    b. deferent
  20. Which of the following types of electromagnetic radiation has the smallest frequency?
    c. radio
  21. A telescope that suffers from chromatic aberration and has a low light gathering power is most likely
    b. a small diameter refracting telescope.
  22. Astronomers build telescopes on tops of mountains because
    • a. there is less air to dim the light.
    • b. the seeing is better.
  23. Galileo's observations of the gibbous phase of Venus proved
    a. that Venus orbited the sun.
  24. Newton concluded that some force had to act on the moon because
    c. a force is needed to pull the moon away from straight-line motion.
  25. __________ has (have) wavelengths that are longer than visible light.
    c. Infrared radiation
  26. The __________ of a telescope is a measure of its ability to show fine detail and depends on the diameter of the objective.
    d. resolving power
  27. Complete the following diagram clearly showing the following:
    • The star groupings.
    • The percentage of stars on each of these groupings.
    • The name of each of these groupings
  28. Name the layers of our sun starting with the first visible layer and work outward.
    • 1. Photosphere
    • 2. Chromosphere
    • 3. Corona
  29. Refracting telescopes suffer from __________ aberration.
    chromatic
  30. The first observations of objects in the solar system that orbited neither the sun nor Earth were made by __________.
    Galileo
  31. Uranus' orbital period is 84 years, how far is Uranus from the sun? _____________
    19 AU
  32. Fill in the following table:
    • Spectral Class: O, B, A. F, G, K, M
    • Temperature(K): 40,000, 20,000, 10,000, 7,500, 5,500, 4,500, 3,000
    • Balkamer Lines: weak, medium, strong, medium, weak, very weak, very weak
    • Other Elements: ionized helium, neutral helium, ionized calcium, ionized calcium, ionized calcium, ionized calcium, titanium oxide
  33. Why would parallaxes be easier to observe if Earth were farther from the sun?
    Larger baseline
  34. What are the current methods used to determine distance?
    • Direct
    • Surveyors
    • Astronomers
    • HR Diagram
  35. What evidence do we have that the sunspots are magnetic?
    Zeeman Effect
  36. What advantages does a large diameter astronomical telescope have over a telescope of a smaller diameter?
    • Better light gathering power
    • Better resolving power
  37. What are Kepler's three laws?
    • planets move in ellipses with the sun at one foci
    • planets vectors sweep equal area in equal time
    • P2 = D3
  38. Describe the differences between the Ptolemaic, Tychonian and Copernican models of the universe.
    • Ptolemy - geocentric
    • Tycho - geocentric and heliocentric (the sun revolved about the earth and the other planets revolve about the sun)
    • Copernicus - heliocentric
  39. How do atmospheric windows limit observations made from Earth's surface?
    Only electromagnetic radiation from the Visual and Radio Windows are allowed to penetrate through the Earth's atmosphere.
  40. If Copernicus overthrew the geocentric universe, what did Kepler overthrow?
    uniform circular motion
  41. What are Newton's three laws of motion.
    • an object at rest/motion will stay so unless acted upon by another force
    • F =MA
    • for every action there is an opposite and equal reaction
  42. Why does it not occur in reflecting telescopes?
    Chromatic abberations are caused by the bending of light passing through a lens, Reflecting telescopes use a mirror as the primary lens to avoid this problem.
  43. Spiral tracers tend to be old, luminous stars.
    FALSE
  44. The density wave theory explains spurs and branches along the spiral arms.
    FALSE
  45. The disk of the galaxy is older than the halo.
    FALSE
  46. The rapid rotation in the outer disk suggests that our galaxy is more massive than previously thought.
    TRUE
  47. The center of our galaxy shows signs of past eruptions.
    TRUE
  48. Shapley found the distance to the center of the galaxy by studying the distance to open clusters.
    FALSE
  49. Neutron stars have densities roughly the same as that of the atomic nucleus.
    TRUE
  50. Theory predicts that neutron stars may not exceed 3 solar masses.
    TRUE
  51. Pulsars could not be pulsating stars because the pulses are too short.
    TRUE
  52. Many pulsars have periods that are gradually increasing as the spinning neutron stars lose energy.
    TRUE
  53. The event horizon marks the boundary within which the density is roughly the same as that of the atomic nucleus.
    FALSE
  54. We expect neutron stars to spin rapidly because they conserve angular momentum.
    TRUE
  55. If the accretion disk around a black hole emits X rays outside the event horizon, the X rays can escape.
    TRUE
  56. When two galaxies collide, they pass through each other and their stars almost never collide.
    TRUE
  57. Cepheid variable stars are more luminous than the sun.
    TRUE
  58. When a large galaxy collides with a small galaxy, the smaller galaxy may be pulled apart by tidal forces.
    TRUE
  59. Elliptical galaxies contain more gas, dust and young stars than do Sa galaxies.
    FALSE
  60. Some large clusters of galaxies do not appear to contain enough mass to hold themselves together.
    TRUE
  61. Double-lobed radio galaxies appear to be emitting jets of gas and radiation.
    TRUE
  62. The rapid fluctuations of quasars show that the objects must be very small.
    TRUE
  63. The look-back time is numerically equal to the distance to a galaxy in light-years.
    TRUE
  64. Some quasars have fuzz around them that produces spectra similar to normal galaxies.
    TRUE
  65. Until recently, most astronomers thought elliptical galaxies were shaped like oblate spheroids.
    TRUE
  66. The rotation curve method can be applied only to pairs of galaxies orbiting each other.
    FALSE
  67. The Milky Way galaxy is not a radio galaxy, it emits no radio radiation.
    FALSE
  68. Quasar red shifts are usually larger than the red shifts of the visible galaxies.
    TRUE
  69. Stars swell into giants when hydrogen is exhausted in their centers.
    TRUE
  70. Helium fusion does not begin until the star has entered the giant region of the H-R diagram.
    TRUE
  71. The sun makes most of its energy by the CNO cycle.
    FALSE
  72. The thermal motions of the atoms in a gas cloud can make it collapse to form a protostar.
    FALSE
  73. No known white dwarf has a mass greater than the Chandrasekhar limit.
    TRUE
  74. The helium flash is the cause of some supernovae.
    FALSE
  75. Even in degenerate matter, pressure depends on temperature.
    FALSE
  76. Because more massive stars have more gravitational energy, they can fuse heavier nuclear fuels.
    TRUE
  77. Hydrostatic equilibrium refers to the balance between weight and pressure.
    TRUE
  78. A nova destroys the star and leaves behind a white dwarf.
    FALSE
  79. Type II supernovae are believed to occur when the cores of a massive stars collapse.
    TRUE
  80. A Type II supernova produces a planetary nebula.
    FALSE
  81. The dust in the interstellar medium can make distant stars look redder than they really are.
    TRUE
  82. The sun has a core in which energy travels outward primarily by radiation.
    TRUE
  83. Giant and supergiant stars are rare because that stage of stellar evolution is short.
    TRUE
  84. Stars less massive than 0.4 solar mass never become giant stars.
    TRUE
  85. Once a star ejects a planetary nebula, it becomes a white dwarf.
    TRUE
  86. Ninety percent of all stars fuse helium to form carbon and lie on the main sequence.
    FALSE
  87. Young star clusters have bluer turn-off points than old clusters.
    TRUE
  88. Planetary nebulae are sites of planet formation.
    FALSE
  89. The sun will eventually become a supernova.
    FALSE
  90. The center of our galaxy lies in the direction of the constellation of
    c.Sagittarius
  91. Which of the following is not a characteristic of the stars of the disk component of our galaxy?
    b.randomly inclined orbits
  92. Radio maps of the spiral arms of our galaxy
    e.map the location of dense neutral hydrogen clouds.
  93. The nuclear bulge of our galaxy
    c.contains stars primarily associated with the spherical component of our galaxy.
  94. The orbits of population I stars
    • I.are confined to disk of the galaxy.
    • III.are nearly circular.
  95. Good spiral tracers are all
    • II.very young.
    • III.very luminous.
  96. The first stars to form in our galaxy
    b.had highly elliptical orbits.
  97. The chemical abundance of population I stars
    b.indicates that the material they formed from had been enriched with material from supernovae.
  98. Although neutron stars are very hot, they are not easy to locate because
    e.they have small surface areas.
  99. An isolated black hole in space would be difficult to detect because
    d.very little matter would be falling into it.
  100. The event horizon
    c. has a radius equal to the Schwarzschild radius.
  101. None of the pulsars emit pulses of visible light because
    e. A few pulsars do emit visible light pulses.
  102. The density of a _________ is greater than the density of a _________.
    d. pulsar white dwarf
  103. The search for black holes involves searching for
    b. x-ray binaries where the compact companion has a mass in excess of 3 M.
  104. As material flows into a black hole
    • a. the material will experience time dilation.
    • b. the material will become hotter.
  105. The first pulsar was discovered by _________ in November of 1967.
    a. Jocelyn Bell
  106. The density of a neutron star is
    c. about the same as an atomic nucleus.

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