Return both exam and scantron sheet when you leave the gym

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1 BROCK UNIVERSITY Page 1 of 17 Final Exam December 2017 Number of pages: 17 Course: ASTR 1P01, Section 1 Number of Students: 465 Date of Examination: December 13, 2017 Number of hours: 2 Time of Examination: 14:00 16:00 Instructor: B.Mitrović No examination aids other than those specified on this examination script are permitted (FHB III: B). Use or possession of unauthorized materials will automatically result in the award of a zero grade for this examination. Students may use a calculator. PLEASE RECORD YOUR STUDENT NAME AND NUMBER ON THE SCANT- RON 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. Red giants are stars that are (a) dim and hot. (b) dim and cool. (c) bright and hot. (d) bright and cool. 2. White dwarfs are stars that are (a) dim and hot. (b) dim and cool. (c) bright and hot. (d) bright and cool. 3. The binary star systems are important because they are used to determine (a) the spectral classes of stars. (b) the distances to stars. (c) the masses of stars. (d) the luminosity classes of stars. 1

2 Course: ASTR1P01 Date: December 13, 2017 page 2 of 17 pages 4. What percentage of the known stars are the main sequence stars? (a) About 1%. (b) About 10%. (c) About 50%. 5. The spectroscopic parallax is a method of determining (a) a star s chemical composition. (b) a star s temperature. (c) a star s distance using H-R diagram. (d) a star s distance from parallax angle. 6. Which of these main sequence stars will have the shortest lifetime? (a) 0.5 solar mass star. (b) 1 solar mass star. (c) 5 solar mass star. (d) 10 solar mass star. 7. Which of these main sequence stars is least luminous? (a) 0.5 solar mass star. (b) 1 solar mass star. (c) 5 solar mass star. (d) 10 solar mass star. 8. Which of these main sequence stars has the largest mass? (a) A star that is 10 times more luminous than the Sun. (b) A star that is 100 times more luminous than the Sun. (c) A star that is 1000 times more luminous than the Sun. (d) A star that is 10,000 times more luminous than the Sun 9. Which of these stars has the cooler surface? (a) A star that emits most energy at 660 nm. (b) A star that emits most energy at 520 nm. 2

3 Course: ASTR1P01 Date: December 13, 2017 page 3 of 17 pages 10. The spectral class of a star provides information about its (a) distance. (b) mass. (c) temperature. (d) luminosity. 11. Two stars have equal surface temperatures but the radius of star A is five times larger than the radius of star B. The luminosity of star A is than the luminosity of star B. (a) 5 times larger (b) 5 times smaller (c) 25 times larger (d) 25 times smaller 12. The parallax angle of a star is 0.05 seconds of arc. Its distance from us in light-years (ly) is about (a) 20 ly. (b) 66 ly. (c) 200 ly. (d) 660 ly. 13. Which stars have the lowest average densities? (a) Red giants. (b) Main sequence stars. (c) White dwarfs. 14. The mass of the Sun is determined from the orbital data (radius of the orbit and the orbital period) of one of the planets using (a) The first Kepler s law. (b) The second Kepler s law. (c) The third Kepler s law as formulated by Newton. 15. Which of these stars have broader absorption lines in their spectra? (a) Red giants. (b) Main sequence stars. 3

4 Course: ASTR1P01 Date: December 13, 2017 page 4 of 17 pages 16. What causes aurorae on Earth? (a) Cosmic rays. (b) Solar wind. (c) Solar neutrinos. 17. Aurorae are more frequent during (a) solar activity minimum. (b) solar activity maximum. 18. What causes the tail of a comet to point directly away from the Sun? (a) Cosmic rays. (b) Solar wind. (c) Solar neutrinos. 19. How long does it take light emitted by the Sun to reach the Earth. The distance between the Earth and the Sun is 150,000,000 km and the speed of light is 300,000 km/s? (a) 5 seconds. (b) 50 seconds. (c) 500 seconds. (d) 5000 seconds. 20. Stars on the main sequence that have a large mass are (a) dim and hot. (b) dim and cool. (c) bright and cool. (d) bright and hot. 21. What is more distant from the Sun? (a) Kuiper belt. (b) Oort cloud. 22. The colour of a star is determined by its luminosity. 4

5 Course: ASTR1P01 Date: December 13, 2017 page 5 of 17 pages 23. Which of the following stars has the coolest surface? (a) K. (b) G. (c) B. (d) F. 24. The spectral lines of a receding star are (a) blueshifted. (b) redshifted. (c) broadened. (d) narrowed. 25. Which of the following stars has the hottest surface? (a) Blue. (b) Yellow. (c) Red. 26. A star that is hot and dim must have (a) a very great distance. (b) a very small mass. (c) a very small radius. (d) a very large radius. 27. Stars with masses in excess of 50 solar masses are not very common. 28. The spectroscopic binaries are detected (a) using spectroscopic parallax. (b) based on their luminosity class. (c) as separate stars in telescopic view. 5

6 Course: ASTR1P01 Date: December 13, 2017 page 6 of 17 pages 29. Typical sizes of main sequence stars (in units of solar radius R ) are (a) from 0.01 R to 0.1 R. (b) from 100 R to 1000 R. (c) from 10 R to 100 R. 30. 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 redshifted. (d) it is blueshifted. 31. What is the most abundant chemical element in the main sequence stars? (a) Oxygen (O). (b) Hydrogen (H). (c) Carbon (C). (d) Helium (He) 32. To determine the luminosity of a star we need to measure its (a) brightness and temperature. (b) brightness and distance. (c) temperature and distance. (d) mass and distance. 33. All of the energy produced in the proton-proton chain is carried away by photons. 34. To determine a star s radius, we need its (a) distance and luminosity. (b) distance and mass. (c) distance and temperature. 6

7 Course: ASTR1P01 Date: December 13, 2017 page 7 of 17 pages 35. The parallax angle for Altair is 0.2 second of arc. Its distance from us in parsec (pc) is (a) 0.2 pc. (b) 5 pc. (c) 16 pc. 36. The closer the star, the larger its parallax angle. 37. Stars U and W have the same luminosity and star U is ten times more distant than star W. The brightness of U is that of W. (a) 1/10 (b) 1/100 (c) 100 times (d) 10 times 38. Stars S and U are equally bright and the luminosity of S is four times larger than the luminosity of U. Then the distance of S is that of U. (a) 1/2 (b) 1/4 (c) 4 times (d) twice 39. The Doppler effect is (a) the change in the observed brightness of a star when it is moving relative to us. (b) the change in the observed wavelength/frequency of light when the light source is moving relative to the observer. (c) the change in the observed luminosity of a star when it is moving relative to us. 40. Which part of the Sun s atmosphere has higher temperature? (a) Chromosphere. (b) Corona. 7

8 Course: ASTR1P01 Date: December 13, 2017 page 8 of 17 pages 41. The surface temperature of the Sun is determined from (a) its distance and luminosity. (b) its distance and brightness. (c) its spectrum using the Wien s law. (d) its spectrum using the Stefan-Boltzmann law. 42. Which planet has the highest orbital speed? (a) Mercury. (b) Venus. (c) Earth. (d) Mars. 43. Which planet has the longest orbital period? (a) Mercury. (b) Venus. (c) Earth. (d) Mars. 44. The center of the Milky Way is a source of radio waves which propagate at the speed of light (300,000 km/s). How long does it take these radio waves to travel the distance from the galactic center to Earth? (a) About 8 minutes. (b) About 30,000 years. (c) About 100,000 years. (d) About million years. 45. How many neutrinos are produced in a single proton-proton chain reaction? (a) One. (b) Two. (c) Four. (d) Six. 46. At present the planet Mars does not have magnetic field. 8

9 Course: ASTR1P01 Date: December 13, 2017 page 9 of 17 pages 47. The layer of the Sun that we normally see is the (a) corona. (b) chromosphere. (c) photosphere. (d) ionosphere. 48. How many positrons are produced in a single proton-proton chain reaction? (a) One. (b) Two. (c) Four. (d) Six. 49. The solar neutrino problem was resolved by experiments in (a) Homestake mine. (b) Brookhaven National Laboratory. (c) Sudbury Neutrino Observatory (SNO). (d) Large Hadron Collider. 50. What is the evidence for the convection currents near the Sun s surface? (a) Sunspots. (b) Prominences. (c) Granulation of the photosphere. (d) Solar flares. 51. The gamma rays produced in the fusion core leave the Sun as photons in the visible part of the spectrum because of (a) the Doppler effect. (b) the gravitational redshift as they lose energy escaping the Sun s gravitational pull. (c) their interaction with the charges in the Sun s interior. (d) their interaction with the solar neutrinos. 52. The mass of 4 He is equal to the total mass of four protons that were used to make it in the fusion reaction. 9

10 Course: ASTR1P01 Date: December 13, 2017 page 10 of 17 pages 53. If the rate of fusion in the core of the Sun spontaneously increased the core would (a) expand and heat up. (b) expand and cool down. (c) contract and heat up. (d) contract and cool down. 54. The production of positrons in the proton-proton chain occurs during (a) fusion of two 3 He nuclei into a 4 He nucleus. (b) fusion of proton and deuterium nucleus into 3 He nucleus. (c) fusion of two protons into deuterium. 55. Asfourprotonsarereplacedbyonenucleus of 4 Heinthefusionprocessthecoretemperature must in order to maintain the same pressure and keep the Sun in hydrostatic equilibrium. (a) decrease (b) stay the same (c) increase 56. The current luminosity of the Sun is the same as it was when it became a main sequence star. 57. In order to calculate the total number of fusion reactions in the Sun every second one would need the Sun s (a) luminosity and mass. (b) luminosity and the energy output of a single proton-proton reaction in the form of radiation. (c) luminosity and the energy carried by neutrinos that were produced in a single proton-proton. 10

11 Course: ASTR1P01 Date: December 13, 2017 page 11 of 17 pages 58. Sunspots are areas on the Sun (a) where the icy comet nuclei struck its surface. (b) less transparent. (c) that are hotter. (d) that are cooler. 59. The first person to observe sunspots through a telescope was (a) Kepler. (b) Galileo. (c) Copernicus. (d) Brahe. 60. The magnetic field within the sunspot is lower than the Sun s average magnetic field. 61. 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 the minimum. (c) the minimum lifetime of a main sequence star. 62. About how many years elapse between times of maximum solar activity? (a) 11. (b) The solar wind is least intense at the times of maximum solar activity. 64. Does the Sun rotate as a solid ball? (a) No, points near the equator rotate in less time. (b) No, points near the poles rotate in less time. (c) Yes, even though it is a gas. (d) Yes, because it is a solid. 11

12 Course: ASTR1P01 Date: December 13, 2017 page 12 of 17 pages 65. What is approximate length of the Solar magnetic cycle? (a) About 11 years. (b) About 22 years. (c) About 33 years. 66. Which of the following has the lowest density? (a) Photosphere. (b) Chromosphere. (c) Corona. 67. A 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. 68. Why are the positrons produced in proton-proton chain? (a) To balance the mass. (b) To balance the electric charge. (c) To balance the number of particles 69. During a high solar activity there is a higher concentration of 14 6 C. 70. Which radiation has the longest wavelength? (a) Radio waves. (b) Microwave. (c) Infrared. (d) Red. 12

13 Course: ASTR1P01 Date: December 13, 2017 page 13 of 17 pages 71. Which photon carries the highest energy? (a) Radio waves. (b) Microwave. (c) Infrared. (d) Red. 72. The largest optical telescopes at present are (a) reflectors. (b) refractors. 73. Which one is the most important power of a telescope? (a) Magnifying. (b) Light-gathering. (c) Resolving. 74. The light-gathering power of a 10-inch telescope is that of a 20-inch telescope. (a) 1/4 (b) four times (c) 1/2 (d) twice 75. Which of the following types of radiation from outer space cannot be detected in a ground-based observatory? (a) Ultraviolet. (b) Radio. (c) X-ray. 76. With a telescope which has Cassegrain focal arrangement the viewing is done from (a) inside the telescope. (b) behind the objective. (c) the side of the telescope. 13

14 Course: ASTR1P01 Date: December 13, 2017 page 14 of 17 pages 77. As seen from the equator (a) no star is a circumpolar star. (b) some stars are circumpolar and some stars rise and set on the horizon. (c) all stars are circumpolar stars. 78. The celestial equator is (a) the projection of the Earth s orbit on the celestial sphere. (b) the projection of the Earth s equator on the celestial sphere. (c) the Sun s apparent path among the stars. 79. 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. 80. The lunar phase at a solar eclipse is (a) full moon. (b) new moon. 81. As seen from Ontario in June the Sun sets (a) north of west. (b) south of west. (c) directly west. 82. Which of the following was a valid argument against the heliocentric model of Aristarchus and later Copernicus? (a) The heliocentric model contradicted the ideas of Aristotle. (b) Things would fall off the Earth if it was moving. (c) Stellar parallax was not observed. 14

15 Course: ASTR1P01 Date: December 13, 2017 page 15 of 17 pages 83. At present the brightest star nearest the north celestial pole is (a) Vega. (b) Polaris. (c) Sirius. (d) Thuban. 84. On June 21, 2018, the number of hours of daylight at the latitude 70 South will be (a) 0. (b) 12. (c) 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) solstice (b) nodal (c) crossing (d) equinox 86. The four seasons, Fall, Winter, Spring and Summer, are caused by (a) changing temperatures of the Sun. (b) the tilt of the Earth s axis. (c) slow precession of the Earth s axis. (d) sunspot cycle. 87. On the first day of Spring, the Sun rises (a) North of East. (b) directly East. (c) South of East. 88. The phase of the Moon between the new moon and the first quarter is called (a) waning crescent. (b) waxing crescent. 89. One can see the third quarter moon at sunset. 15

16 Course: ASTR1P01 Date: December 13, 2017 page 16 of 17 pages 90. On December 3 the moon was full. On what day (approximately) will it be new? (a) December 18. (b) January 3, The full moon sets at (a) midnight. (b) sunrise. (c) noon. (d) sunset. 92. The first quarter moon rises at (a) midnight. (b) sunrise. (c) noon. (d) sunset. 93. You can observe the waxing gibbous moon at sunrise. 94. Who was the first to determine the circumference/radius of the Earth? (a) Aristotle. (b) Aristarchus. (c) Eratosthenes. (d) Ptolemy. 95. The first Kepler s law is a statement about (a) the shape of planetary orbits. (b) the variation in the speed of a planet as it orbits the Sun. 96. The lunar phase at a lunar eclipse is (a) full moon. (b) new moon. 16

17 Course: ASTR1P01 Date: December 13, 2017 page 17 of 17 pages 97. A planet moves fastest when it is closest to the Sun 98. Which of the following astronomers obtained accurate data on planetary orbits? (a) Brahe. (b) Copernicus. 99. Which of the following astronomers found that gravity is responsible for keeping the Moon in its orbit around the Earth? (a) Newton. (b) Kepler Which of the following observations by Galileo was the strongest evidence for heliocentric model? (a) The moons of Jupiter. (b) Stellar parallax. (c) The sunspots. (d) The gibbous and the quarter phases of Venus. 17