BROCK UNIVERSITY. 1. Stars are born in regions of space containing

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1 BROCK UNIVERSITY Page 1 of 18 Final Exam: December 2013 Number of pages: 18 Course: ASTR 1P01, Section 2 Number of students: 475 Examination date: 16 December 2013 Time limit: 2 hours Time of Examination: 20:00 22:00 Instructor: S. D Agostino Answer all questions on the scantron sheet provided. No aids permitted except for a non-programmable calculator. Each question is worth 1 mark. Total number of marks: Stars are born in regions of space containing (a) enormous clouds of gas and dust. (b) interstellar birthing rooms. (c) gigantic stork-like intergalactic structures. (d) branch plants of ProtoStar Inc. 2. Which length is smallest? (a) One AU. (b) One light-second. (c) The diameter of a typical star. (d) The diameter of a typical planet. 3. Which length is largest? (a) The diameter of a typical planet. (b) One AU. (c) One light-second. (d) The diameter of a typical star. 4. The speed of light is (a) 300,000 km/h. (b) 300 km/h. (c) 300,000 km/s. (d) 300 km/s. 5. What does it mean to say that the universe is expanding? (a) Everything in the universe is increasing in size. (b) Individual galaxies are increasing in size. (c) The average distances between star systems within galaxies is increasing. (d) The average distances between galaxies is increasing.

2 ASTR 1P01 December 2013 Page 2 of The Big Bang created (a) the universe and the stars. (b) the universe and the galaxies. (c) the universe, the galaxies and the stars. (d) just the universe. 7. About how long does it take for light to travel from the Sun to Pluto? (a) 5 minutes (b) 5 seconds (c) 5 hours (d) 5 years 8. About how long does it take for light to travel from the Sun to the Earth? (a) 8 years (b) 8 hours (c) 8 minutes (d) 8 seconds 9. Overall, the universe appears to be (a) contracting, but at a rate that appears to be increasing. (b) contracting, but at a rate that appears to be decreasing. (c) expanding, but at a rate that appears to be increasing. (d) expanding, but at a rate that appears to be decreasing. 10. The star nearest to the Sun is at a distance of about (a) 4 thousand light-years. (b) 4 AU. (c) 4 parsecs. (d) 4 light-years. 11. Most asteroids orbit the Sun between the orbits of (a) Mars and Jupiter. (b) Venus and Earth. (c) Jupiter and Saturn. (d) Neptune and Pluto.

3 ASTR 1P01 December 2013 Page 3 of The evidence for the existence of dark matter within galaxies is that (a) there appears to be a weak repulsive force between visible matter particles within a galaxy. (b) it emits no observed radiation. (c) visible matter within galaxies appears to be influenced by more force than can be accounted for by visible matter closer to the centre of the galaxy. (d) there is a bright matter/dark matter duality similar to wave-particle duality. 13. A waning crescent moon rises (a) between sunrise and noon. (b) between noon and sunset. (c) between sunset and midnight. (d) between midnight and sunrise. 14. A waxing gibbous moon rises (a) between sunrise and noon. (b) between noon and sunset. (c) between sunset and midnight. (d) between midnight and sunrise. 15. The third quarter moon sets at about (a) midnight (b) sunrise. (c) noon. (d) sunset. 16. If a star rises tonight at 10:00 pm, tomorrow it will rise at about (a) 10:00 pm. (b) 9:56 pm. (c) 10:04 pm. (d) [It depends on the season.] 17. An equinox is a position on the Earth s orbit for which (a) the Earth is closest to the Sun. (b) the Earth is equally close to the near point and far point from the Sun. (c) the day and night are equally long. (d) the Sun stops its northward or southward movement.

4 ASTR 1P01 December 2013 Page 4 of As seen from the Earth s equator, the north celestial pole is (a) at the zenith. (b) at the nadir. (c) on the horizon. (d) on the ecliptic. 19. The dates of solar eclipses get shifted from one year to the next because of (a) precession of the Earth s rotational axis. (b) precession of the equinoxes. (c) precession of the Moon s orbit. (d) precession of the solstices. 20. Eclipses can possibly occur about once every (a) month. (b) three months. (c) six months. (d) nine months. 21. The Moon s orbit is tipped relative to the Earth s orbit at an angle of about (a) 66.5 degrees. (b) 23.5 degrees. (c) 5 degrees. (d) 0.5 degrees. 22. The Sun appears to travel south, then north, then south again during the year. The extreme north and south points of this apparent journey are called points. (a) nodal (b) crossing (c) solstice (d) equinox 23. The four seasons, Fall, Winter, Spring and Summer, are caused by (a) changing temperatures of the Sun. (b) the 23.5 tilt of the Earth s rotation axis. (c) the precession of the Earth s rotation axis. (d) the sunspot cycle.

5 ASTR 1P01 December 2013 Page 5 of On the first day of Spring, the Sun sets (a) north of west. (b) directly west. (c) south of west. 25. As described by Kepler s third law of planetary motion, (a) planets closer to the Sun have longer periods. (b) the period of a planet depends on the shape of its orbit, not its distance from the Sun. (c) planets closer to the Sun have shorter periods. (d) the period of a planet is a sinusoidal function of its distance from the Sun. 26. Which of the following was a valid argument against the heliocentric model proposed by some ancient Greek astronomers? (a) The Earth would lose its Moon if it were revolving around the Sun. (b) The heliocentric model contradicted the ideas of Aristotle. (c) Things would fall off the Earth if it were moving. (d) Stellar parallax was not observed. 27. Epicycles were introduced into the ancient geocentric model of the solar system in an attempt to (a) better describe planetary motions. (b) account for anomalies in the motion of the Sun. (c) better predict eclipses. (d) explain why the planets have different rotational periods. 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 first use of telescopes in astronomy was by (a) Galileo. (b) Kepler. (c) Brahe. (d) Copernicus.

6 ASTR 1P01 December 2013 Page 6 of An advantage of the Renaissance heliocentric model of the solar system (over the geocentric model) is that (a) apparent retrograde motions of planets is easier to explain. (b) stellar parallax is easier to measure. (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. Which of the following astronomers determined that gravity is responsible for keeping the Moon in its orbit around the Earth? (a) Copernicus. (b) Galileo. (c) Newton. (d) Kepler. 32. The prevailing medieval view was that the planets were mounted on crystalline spheres. However, an observation by in 1577 of a comet that crossed the orbits of the planets (and therefore would have had to pierce the crystalline spheres), and was not inside Earth s atmosphere, as previously thought, helped humans to advance their simplistic views of the heavens. (a) Brahe (b) Kepler (c) Galileo (d) Copernicus 33. The prevailing medieval view was that the heavens were perfect and that the stars were eternal and unchanging. An observation of a supernova in 1572 by showed that an object far beyond the solar system did indeed change, and so helped humans to advance their simplistic views of the heavens. (a) Brahe (b) Kepler (c) Galileo (d) Copernicus 34. One of Copernicus s great advances was to (a) determine the relative size of each planet. (b) determine the relative brightness of each planet. (c) determine the composition of the atmosphere of each planet. (d) determine the relative distances of each planet from the Sun.

7 ASTR 1P01 December 2013 Page 7 of Kepler s first law of planetary motion is a statement about (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. It is possible to determine the mass of a planet from the orbital data (the period and the orbital radius) of one of its satellites. (a) True. (b) False. 38. According to Newton s laws of motion the acceleration of a body (a) is proportional to its mass and inversely proportional to the net force acting on it. (b) is is proportional to the product of its mass and the net force acting on it. (c) is inversely proportional to the square of the net force acting on it. (d) is proportional to the net force acting on it and inversely proportional to its mass. 39. Inertia is (a) the tendency of a body not to move. (b) the tendency of gases such as neon and argon not to enter into chemical reactions. (c) the tendency of fluids to remain moving in circles without turbulence. (d) the tendency of a body to remain at rest or moving in a straight line at constant speed. 40. We can tell that the net force acting on the Earth is not zero because (a) the Earth is motionless. (b) repeated measurements with very precise force balances have shown that the net force acting on the Earth is not zero. (c) of precise measurements of the motion of the Moon. (d) the Earth s path around the Sun is not a straight line.

8 ASTR 1P01 December 2013 Page 8 of The first scientist to propose that there must exist some force that holds the planets in their orbits (and in fact he incorrectly proposed that it is a magnetic force) was (a) Kepler. (b) Galileo. (c) Newton. (d) Copernicus. 42. The first scientist to propose a theory of gravity that was mathematical and to prove that an inverse-square force of gravity is consistent with celestial observations was (a) Huygens. (b) Hooke. (c) Galileo. (d) Newton. 43. Newton s third law of motion states that when two objects interact, (a) the acceleration of object A is equal in magnitude and opposite in direction to the acceleration of object B. (b) the velocity of object A is equal in magnitude and opposite in direction to the velocity of object B. (c) the acceleration of object A is equal in magnitude and opposite in direction to the acceleration of object B, and the velocity of object A is equal in magnitude and opposite in direction to the velocity of object B. (d) [None of the above.] 44. The magnitude of the gravitational force that the Earth exerts on the Moon is equal to the magnitude of the gravitational force that the Moon exerts on the Earth. Therefore, (a) the resulting acceleration of the Earth is much less than the resulting acceleration of the Moon, because the Earth is much more massive than the Moon. (b) the resulting acceleration of the Earth is much less than the resulting acceleration of the Moon, because the Earth is much less massive than the Moon. (c) the resulting acceleration of the Earth is much greater than the resulting acceleration of the Moon, because the Earth is much more massive than the Moon. (d) the resulting acceleration of the Earth is much greater than the resulting acceleration of the Moon, because the Earth is much less massive than the Moon. 45. Your weight is (a) the same on Earth as it is on the Moon. (b) greater on Earth than it is on the Moon. (c) less on Earth than it is on the Moon. (d) [It depends on your state of motion in each location.]

9 ASTR 1P01 December 2013 Page 9 of Which type of radiation has the longest wavelength? (a) Microwave. (b) Infrared. (c) Red. (d) Radio wave. 47. Red and green light differ because (a) they have different wavelengths. (b) they have a different particle densities. (c) the sizes of their particles are different. (d) the weights of the light beams are different. 48. Infrared radiation differs from red light in (a) the diameter of its photons. (b) its speed in vacuum. (c) its wavelength. (d) the mass of its photons. 49. Which type of photon has the lowest energy? (a) Red light. (b) Blue light. (c) Microwave radiation. (d) Yellow light. 50. Which type of radiation has the longest wavelength? (a) Ultraviolet (UV). (b) Blue light. (c) Gamma rays. (d) X-rays. 51. Which type of radiation has the shortest wavelength? (a) Red light. (b) Infrared. (c) Blue light. (d) Microwave.

10 ASTR 1P01 December 2013 Page 10 of Which type of photon has the highest energy? (a) Radio wave. (b) Microwave. (c) Infrared. (d) Red. 53. When a star s light passes through its cooler atmosphere (a) new spectral lines appear in the spectrum. (b) photons of certain wavelengths are absorbed. (c) it is red-shifted. (d) it is blue-shifted. 54. Continuous spectra are produced by (a) only gases. (b) solids or low-density gases. (c) solids or high-density gases. (d) only solids. 55. We can learn a lot about a star from its spectrum. All of the following statements is true except one. Which one is false? (a) We can look at Doppler shifts of spectral lines to determine the star s speed towards or away from us. (b) We can identify chemical elements present in the star 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) a spectrum that depends on the speed of the white light. (b) an absorption line spectrum. (c) an emission line spectrum. (d) a spectrum that depends on the wavelength of the white light. 57. Wien s law is typically used in astronomy to (a) determine the temperature of a star. (b) determine the wavelength of maximum emission of a star. (c) determine a star s spectral type. (d) determine a star s chemical composition.

11 ASTR 1P01 December 2013 Page 11 of When an electron in an atom makes a transition from a higher energy level to a lower energy level, the atom (a) absorbs a photon of a specific frequency. (b) can emit a photon of any frequency. (c) can absorb a photon of any frequency. (d) emits a photon of a specific frequency. 59. If you heat a gas so that collisions are continually elevating electrons to higher energy levels, when the electrons fall back to lower energy levels, the gas produces (a) an emission line spectrum. (b) an absorption line spectrum. (c) thermal radiation. (d) radio waves. 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. You observe two stars, one blue and the other red. What can you conclude? (a) The blue star is hotter than the red star. (b) The red star is hotter than the blue star. (c) The red star is larger than the blue star. (d) The blue star is larger than the red star. 62. The largest optical telescopes at present are (a) refractors. (b) reflectors. (c) diffractors. (d) speculators. 63. Protons and neutrons in an atomic nuclues are held together by (a) electromagnetic forces. (b) strong nuclear forces. (c) weak nuclear forces. (d) gravitational forces.

12 ASTR 1P01 December 2013 Page 12 of Which is the most important power of a telescope? (a) Magnifying. (b) Light-gathering. (c) Resolving. (d) Speculating. 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. With a telescope that has a Newtonian focal arrangement, the viewing is done from (a) inside the telescope. (b) behind the objective. (c) the side of the telescope. (d) in front of the telescope. 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.

13 ASTR 1P01 December 2013 Page 13 of 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 75% hydrogen, about 25% helium, and less than 2% heavier elements (b) about 50% hydrogen, about 50% helium, and less than 2% heavier elements (c) about 60% hydrogen, about 40% 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 characteristic most determines how they will differ? (a) The time at which they were formed. (b) Their initial luminosity. (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 larger is its parallax angle. (a) True. (b) False. 75. The percentage of known stars that are main-sequence stars is about (a) 1%. (b) 10%. (c) 50%. (d) [None of the above.]

14 ASTR 1P01 December 2013 Page 14 of 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.

15 ASTR 1P01 December 2013 Page 15 of 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. What causes aurorae on Earth and some other planets? (a) X-rays. (b) Gamma rays. (c) Cosmic rays. (d) Solar wind. 84. A solar prominence is (a) a boundary between the fusion core and the radiation zone. (b) a boundary between the radiation zone and the convection zone. (c) a reaction within the Sun s core. (d) a huge plume of glowing gas that juts from the lower chromosphere into the corona. 85. The layer of the Sun that we normally see is the (a) corona. (b) chromosphere. (c) ionosphere. (d) photosphere. 86. Which of the following parts 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.

16 ASTR 1P01 December 2013 Page 16 of The diameter of the Sun is about times the Earth s diameter. (a) 10 (b) 100 (c) 1,000 (d) 1,000, The Sun s mass is about times the Earth s mass. (a) 30 (b) 300 (c) 3,000 (d) 300, Granulation of the Sun s surface is a direct consequence of (a) heat conduction. (b) convection. (c) random walk of photons. (d) heat radiation. 91. The Sun is supported against the crushing force of its own gravity by (a) its rapid rotation. (b) gas pressure. (c) pressure created by escaping neutrinos. (d) magnetic forces. 92. Sunspots are areas on the Sun (a) where icy comet nuclei struck its surface. (b) that are less transparent. (c) that are hotter. (d) that are cooler.

17 ASTR 1P01 December 2013 Page 17 of The Maunder minimum refers to (a) the lowest temperature at which hydrogen fusion takes place. (b) the layer on the Sun s surface where the temperature is at a minimum. (c) the minimum lifetime of a main-sequence star. (d) [None of the above.] 94. About years elapse between times of maximum solar activity. (a) 11 (b) 22 (c) 2 (d) 4.6 billion 95. Sunspots appear dark because (a) they are fairly bright but appear dark against the even brighter background of the surrounding surface. (b) they are too cold to emit any visible light. (c) they are holes in the solar surface through which we can see to deeper, darker layers of the Sun. (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. When four hydrogen nuclei fuse to form a helium nucleus, the total mass at the end is the total mass at the beginning. (a) more than (b) the same as (c) less than (d) not related to

18 ASTR 1P01 December 2013 Page 18 of 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 burned up already. (c) there would be more carbon in its atmosphere. (d) of the greenhouse effect. 99. The nuclear fusion of hydrogen into helium inside a star begins at a temperature of (a) at least 1 million degrees. (b) at least 10 million degrees. (c) at least 100 million degrees. (d) at least 1 billion degrees Ockham s razor (a) suggests that for scientific theories with equal predictive power, the simpler theory is better. (b) was the forerunner of the modern twin-blade razors. (c) is misused by economists to give hair cuts to countries struggling with debt. (d) was cited in a medieval barber s manual known as the Almagest.