Answers
1. b. James Clerk Maxwell
2. d. the nucleus repels the electrons which move around it
3. a. electric charges that were in motion
4. e. it consists of charged particles given off by the nuclei of atoms
5. c. its wavelength is much longer than the wavelength of the light you see reflected from the page of this exam
6. e. you can't fool me, all of these travel through space at the same speed
7. b. the speed of light
8. c. wavelength
9. a. radio
10. b. gamma rays
11. b. a unit of frequency
12. d. red
13. c. a photon of light cannot pass through the atmosphere of the Earth, and thus cannot be seen at the Earth's surface
14. c. decrease as the distance squared
15. e. radio waves of the wavelength that carry FM broadcasts
16. a. the ozone layer
17. d. it is the band of the spectrum where the Sun puts out the most energy
18. b. it was first discovered in 1800 in an experiment using sunlight and thermometers
19. d. the sound waves coming from your transistor radio
20. d. No, because AM radio waves are bounced back or scattered by the ionosphere
21. b. their temperature
22. a. heat
23. e. a cube of the Sun
24. c. a blackbody
25. e. all of the above
26. b. making a blackbody curve and finding the wavelength of the peak (maximum)
27. d. about 16 times the energy of the second
28. e. more than one of the above
29. a. measuring how bright sources of light in the universe appear
30. c. an emission spectrum
31. e. more than one of the above
32. d. Helium
33. c. very small (perhaps the size of a soccer ball) and in the middle
34. b. hydrogen
35. c. isotopes
36. d. only remain stable for an extremely small fraction of a second
37. b. Niels Bohr
38. d. because the spacing of the energy levels is different in different atoms
39. a. ionized
40. a. a photon is given off
41. c. look at the absorption lines in its spectrum
42. b. infra-red
43. c. radar waves
44. b. the frequency of a wave to its energy
45. d. the waves of a dental x-ray
46. c. some radio waves
47. e. telescopes
48. a. collect as much light as possible and bring it to a focus
49. b. Galileo Galilei
50. c. aperture
51. d. it is recorded using an electronic detector called a CCD for later analysis
52. b. refractors
53. c. Cassegrain focus
54. d. mirror
55. d. the Keck Telescope in Hawaii
56. d. all of the above
57. c. refracting
58. d. a large reflector located in orbit above the Earth's atmosphere
59. b. compensate for changes in the Earth's atmosphere and achieve better resolution
60. a. because the Earth is rotating with the telescope
61. c. a series of glass plates, with light-sensitive chemicals on them, on which the appearance of the sky is recorded
62. e. a telescope
63. b. a radio telescope
64. a. heat your telescope, so its delicate optics are not cold
65. a. x-ray telescope
66. c. a spectrometer
67. b. Yerkes Observatory
68. d. on a tall, dry mountain peak
69. a. Karl Jansky
70. c. we can connect several radio telescopes some distance apart together electronically to give us the resolution of a larger telescope
71. e. a large metal dish
72. e. the Very Long Baseline Array of Radio Telescopes, stretching from the Virgin Islands to Hawaii
73. c. the Hubble has a larger aperture than any visible-light telescope on Earth
74. d. an airplane with an infra-red telescope on board designed to fly above much of the water vapor in the Earth's atmosphere
75. d. the Keck Telescope
76. d. the mirror's shape was slightly off, so all the light did not come to a single focus
77. c. very hot stars
78. b. Einstein
79. e. the diameter of the primary lens or mirror
80. b. Compton Observatory
81. d. is made entirely of hot gas
82. b. photosphere
83. e. we take an absorption line spectrum of the Sun, and the absorption lines tell us what elements are present in the outer layers
84. c. hydrogen
85. a. chromosphere
86. b. the density (number of atoms in a unit volume) decreases
87. c. during total eclipses of the Sun
88. b. spicules
89. c. corona
90. a. corona
91. c. the Sun's magnetic field interacting with the charged particles that make up the atmosphere
92. e. by noting the wind's effects on the tails of comets
93. d. coronal holes
94. a. aurorae (northern and southern lights)
95. c. hot material must be rising from the Sun's hotter interior
96. e. they are cooler than the material around them (although still very hot compared to Earth temperatures)
97. b. The number of sunspots gets larger and smaller over the course of 11 years
98. d. the measure the Zeeman effect (the splitting of spectral lines)
99. c. It was a time of solar maximum, and there had been a flare on the Sun
100. e. granulation
101. b. loops of magnetic field emerging from the surface of the Sun
102. d. all of the above
103. b. a climate with cooler temperatures
104. c. electrons and protons
105. e. plages
106. c. the dating of radioactive rocks show that the Earth and the Sun are billions of years old
107. d. The process was not well understood until the 1930's
108. e. more than one of the above
109. b. a slow contraction
110. a. nuclear fusion
111. c. a little bit of mass can be converted into a substantial amount of energy
112. e. the speed of light
113. d. positron
114. e. energy in the form of a gamma ray
115. d. when equal amounts of matter and antimatter meet, they become pure energy
116. e. all of the above
117. c. the nuclear force, which is attractive and stronger than electricity, holds the nucleus together
118. a. a neutrino
119. c. the nuclear force which holds nuclei together
120. c. some of the energy in their mass is released
121. e. nuclear fission
122. b. for hydrogen nuclei to fuse, they must get very close to each other, which the nuclei in the oceans cannot do
123. a. only in the core
124. b. there are an enormous number of protons inside the Sun, so some will fuse much sooner than the average
125. c. two protons
126. e. a form of helium
127. d. a helium nucleus
128. c. a little bit of mass is lost in each reaction and is turned into energy (the Sun is losing mass)
129. b. it quickly collides with an electron and turns into gamma-ray energy
130. c. nuclear fusion in the core keeps the temperature and the pressure inside the Sun at a high enough level so that gravity is balanced
131. a. convection
132. c. a neutrino
133. b. the core
134. b. study the oscillations (pulsations) of the Sun's surface
135. d. measuring the pulsations of the Sun from stations around the world
136. e. The experiments have found only between 1/3 and 2/3 the number of neutrinos arriving from the Sun that our models predicted should be coming
137. b. looking for changes in the Doppler shift of lines in the atmosphere of the Sun
138. d. how much energy the star gives off each second
139. c. nine times fainter
140. e. it could be more than one of the above; there is no way to tell which answer is right by just looking at the star
141. d. measuring the brightness of different stars
142. a. Hipparchus
143. d. a star with magnitude -1
144. b. because the luminosity tells us how bright a star really is, while apparent brightness only tells us how bright it happens to look from Earth
145. c. blue-violet
146. c. M
147. b. have different temperatures
148. e. in the hottest stars, hydrogen atoms are ionized, and so there are no electrons to produce lines in the spectrum
149. a. decreasing surface temperature
150. d. M
151. b. Annie Cannon
152. c. since helium shows lines only in hot stars, this star must be relatively cool
153. d. by looking at the Doppler shift in the lines of the star's spectrum
154. a. a shift in the spectral lines toward the blue end (as compared to the laboratory positions of these lines)
155. d. proper motion
156. d. because of proper motion, a number of the familiar constellations will look somewhat different in a million years
157. c. stars that rotate have much wider lines in their spectra than stars that do not
158. c. more luminous (intrinsically brighter) than the Sun
159. d. these stars are intrinsically so luminous, that they can easily be seen even across great distances
160. b. because such very luminous stars are extremely rare, and thus any small neighborhood in the Galaxy is unlikely to contain one of them
161. a. low luminosity compared to the Sun
162. d. its mass
163. e. binary stars
164. c. an analysis of the ways the lines in the spectrum change allows us to calculate the star's distance directly
165. d. that the lines in its spectrum show a blue-shift
166. b. Kepler's Third Law
167. d. brown dwarfs
168. b. a planet
169. a. its spectrum showed the molecule methane in the object's atmosphere
170. c. stars are so far away, we cannot resolve (distinguish) their diameters
171. d. eclipsing binary stars
172. c. surface temperature
173. b. along the bottom (the horizontal axis)
174. c. Hertzsprung
175. b. the main sequence
176. c. it must be quite large in size
177. b. smaller in diameter
178. e. in the lower right, among the least luminous main sequence stars
179. d. near the very top of the main sequence, in the upper left
180. b. fusing hydrogen into helium in their cores
181. c. masses
182. c. among the stars at the bottom right of the main sequence
183. c. the same luminosity
184. d. one ten-millionth of the distance from the Earth's equator to its pole
185. c. measure the distance directly to any object orbiting the Sun
186. e. the average distance between the Earth and the Sun
187. a. bouncing radar beams off them
188. b. because the stars are so far away that their annual shift of position in the sky is too small to see without a telescope
189. c. one half the angle that a star shifts when seen from opposite sides of the Earth's orbit
190. b. 5 parsecs
191. d. 32.6 years
192. d. the Hipparcos satellite
193. b. measuring the star's parallax
194. b. the Cepheid variables
195. a. time
196. c. they can measure a regularly varying Doppler shift in the spectral lines
197. d. the first such variable was discovered in a constellation called Cepheus
198. b. Henrietta Leavitt
199. d. the length of time they took to vary
200. e. Polaris