Download Test 2, Nov. 17, 2015 - Physics@Brock

Brock University
Number of pages: 9
Number of Students: 500
Number of hours: 50 min
Instructor: B.Mitrović
Test 2, November 2015
Course: ASTR 1P01
Date of Examination: November 17, 2015
Time of Examination: 17:00–17:50
1. Galileo’s observation of the gibbous and the quarter phases of Venus supported
(a) the geocentric model.
(b) the heliocentric model.
2. According to Kepler’s second law, a planet moves fastest when it is
(a) closest to the Sun.
(b) at the greatest distance from the Sun.
(c) [The speed of the planet does not depend on its distance from the Sun.]
3. 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.
4. Which radiation has the shortest wavelength?
(a) Infrared.
(b) Red light.
(c) Blue light.
(d) X-ray.
5. Which photons carry the least amount of energy?
(a) Infrared.
(b) Red light.
(c) Blue light.
(d) X-ray.
6. Which of the following features determines the light gathering power of a telescope?
(a) the diameter of the objective.
(b) the diameter of the eyepiece.
(c) the focal length of the objective.
(d) the focal length of the eyepiece.
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Course: ASTR1P01
Date: November 17, 2015
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7. Which eyepiece gives a higher magnification in a given telescope?
(a) Eyepiece with the focal length of 5 cm.
(b) Eyepiece with the focal length of 10 cm.
8. Which telescope has a higher resolving power?
(a) Telescope with 15 cm wide objective.
(b) Telescope with 20 cm wide objective.
9. Lenses focus all colours at the same point.
(a) True.
(b) False.
10. Mirrors focus all colours at the same point.
(a) True.
(b) False.
11. A telescope which has a hole in the middle of the primary mirror to allow light reflected
from its secondary mirror to reach a focus behind the primary mirror is said to have
focal arrangement.
(a) Newtonian.
(b) Cassegrain.
(c) Galilean.
(d) Copernican.
12. The Earth’s atmosphere is transparent to X-rays from outer space.
(a) True.
(b) False.
13. If a star is 50 parsec (pc) away, what is its approximate distance in light years (ly)?
(a) 1.6
(b) 16
(c) 160
(d) 1,600
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14. Two stars, S and U have the same luminosity (L) but the distance of S is five times that
of U. The brightness of S is
that of U.
(a)
(b)
1
.
5
1
.
25
(c) 5 times.
(d) 25 times.
15. Star S radiates most energy at 400 nanometers and star U radiates most energy at 700
nanometers. From this we can conclude that
(a) star S has hotter surface than star U.
(b) star S has colder surface than star U.
(c) both stars have the same surface temperature.
(d) [No comparison of their surface temperatures can be made.]
16. A photon can be absorbed by an atom only if the photon energy is equal to the energy
difference of two atomic energy levels.
(a) True.
(b) False.
17. Star Betelgeuse in Orion is 120,000 times more luminous than the Sun, yet its surface
temperature is about half of that of the Sun. This implies that
(a) the Sun’s radius is much larger than the radius of Betelgeuse.
(b) the Sun’s radius is much smaller than the radius of Betelgeuse.
(c) radii are the same.
(d) [No comparison of their radii can be made.]
18. Which of these forces binds electrons to the nucleus?
(a) Gravitational.
(b) Electrical.
(c) Strong nuclear.
(d) Weak nuclear.
19. The chemical element helium was first detected
(a) on the Earth.
(b) in the spectrum of the Sun.
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Date: November 17, 2015
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20. When a star’s light passes through its cooler atmosphere
(a) it is redshifted.
(b) new spectral lines appear in the spectrum.
(c) it is blueshifted.
(d) photons of certain wavelengths are absorbed.
21. To determine a star’s radius, we need its
(a) distance and mass.
(b) temperature and luminosity.
(c) distance and luminosity.
(d) [None of the above.]
22. Which of these forces binds together the protons and the neutrons in a nucleus?
(a) Gravitational.
(b) Electrical.
(c) Strong nuclear.
(d) Weak nuclear.
23. Which of the following stars has the hottest surface?
(a) K.
(b) G.
(c) B.
(d) F.
24. The center of mass in a binary system is closer to
(a) the more massive of the two stars.
(b) less massive of the two stars.
25. The spectral lines of an approaching star are
(a) broadened.
(b) narrowed.
(c) blueshifted.
(d) redshifted.
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Date: November 17, 2015
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For Questions 26-35 refer to Figure 1.
Figure 1
26. The Sun is represented in the diagram by
(a) S3 .
(b) S4 .
(c) S5 .
(d) S6 .
27. Among the main sequence stars, the one that is expected to live for the shortest period
of time is
(a) S1 .
(b) S3 .
(c) S6 .
(d) S7 .
28. Comparing stars S3 and S4 , which one is expected to live longer?
(a) S3 .
(b) S4 .
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29. Which of the following stars is a red giant?
(a) S3 .
(b) S7 .
30. Stars S6 and S7 have the same temperature, but star S6 is less luminous than star S7
because
(a) it has a larger radius.
(b) it has a smaller radius.
(c) it is a main sequence star.
(d) it is closer.
31. Which of the following stars is a white dwarf?
(a) S3 .
(b) S6 .
(c) S7 .
(d) [None of the above.]
32. Comparing stars S3 and S7 , which one has the larger radius?
(a) S3 .
(b) S7 .
33. Which of the following stars is a main sequence star?
(a) S1 .
(b) S2 .
(c) S3 .
(d) S7 .
34. Which of the following stars has the largest mass?
(a) S3
(b) S4
(c) S5
(d) S6
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Date: November 17, 2015
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35. The main sequence star with the smallest mass is
(a) S1 .
(b) S3 .
(c) S6 .
(d) S7 .
36. Stars on the main sequence that have a small mass are
(a) dim and hot.
(b) dim and cool.
(c) bright and cool.
(d) bright and hot.
37. A star’s distance can be determined using its spectral class and its luminosity class.
(a) True.
(b) False.
38. White dwarfs have much higher densities than the main sequence stars.
(a) True.
(b) False.
39. A star that is cool and very luminous must have
(a) a very great distance.
(b) a very large radius.
(c) a very small mass.
(d) a very small radius.
40. Stars with masses in excess of 50 solar masses are very common.
(a) True.
(b) False.
41. The spectroscopic binaries are detected
(a) as separate stars in telescopic view.
(b) using spectroscopic parallax.
(c) based on oscillating Doppler shifts of their spectral lines.
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Course: ASTR1P01
Date: November 17, 2015
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42. Typical sizes of main sequence stars (in units of solar radius R⊙ ) are
(a) from 0.01 to 0.1 R⊙ .
(b) from 0.1 to 10 R⊙ .
(c) from 100 R⊙ to 1000 R⊙ .
43. The combination of hydrogen and helium make up about 98% of all the mass of the Sun.
(a) True.
(b) False.
44. Which of the following is the thinnest layer of the Sun?
(a) Corona.
(b) Chromosphere.
(c) Photosphere.
(d) Radiative layer.
(e) Convection layer.
45. The Sun’s outer atmosphere is called
(a) ionosphere.
(b) photosphere.
(c) corona.
(d) chromosphere.
46. The diameter of the Sun is about
times the Earth’s diameter.
(a) 1,000,000
(b) 1,000
(c) 100
(d) 10
47. The Sun’s mass is about
times larger than the Earth’s mass.
(a) 30
(b) 300
(c) 3,000
(d) 300,000
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Course: ASTR1P01
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48. The Sun’s lower atmosphere is called
(a) corona.
(b) chromosphere.
(c) ionosphere.
(d) photosphere.
49. The layer of the Sun that we normally see is the
(a) ionosphere.
(b) photosphere.
(c) corona.
(d) chromosphere.
50. The surface temperature of the Sun in degrees Kelvin is about
(a) 6,000,000.
(b) 60,000.
(c) 6000.
(d) 600.
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