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2. Question 1 Stellar parallax is used to measure the sizes of stars.
distances of stars.
temperatures of stars.
radial velocity of stars.
brightness of stars.
Answer: b
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3. Question 1 Stellar parallax is used to measure the sizes of stars.
distances of stars.
temperatures of stars.
radial velocity of stars.
brightness of stars.
Explanation: Parallax can be used to measure distances to stars accurately to about 200 parsecs (650 light-years).
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4. Question 2 The angle of stellar parallax for a star gets larger as the
distance to the star increases.
size of the star increases.
size of the telescope increases.
length of the baseline increases.
wavelength of light increases.
Answer: d
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5. Question 2 The angle of stellar parallax for a star gets larger as the
distance to the star increases.
size of the star increases.
size of the telescope increases.
length of the baseline increases.
wavelength of light increases.
Explanation: Astronomers typically make observations of nearby stars 6 months apart, making the baseline distance equal to 2 AU (astronomical units).
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6. Question 3
You can best model the size and distance relationship of our Sun and the next nearest star using
one tennis ball here and one on the Moon.
two beach balls separated by 100 city blocks.
two grains of sand 100 light-years apart.
two golf balls 100 km apart.
two baseballs 100 yards apart.
Answer: d
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7. Question 3
You can best model the size and distance relationship of our Sun and the next nearest star using
one tennis ball here and one on the Moon.
two beach balls separated by 100 city blocks.
two grains of sand 100 light-years apart.
two golf balls 100 km apart.
two baseballs 100 yards apart.
Explanation: The Sun is about 1 million miles in diameter. The next nearest star is about 25 million times farther away.
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8. Question 4 A star’s proper motion is its true motion in space.
apparent shift as we view from opposite sides of Earth’s orbit every 6 months.
annual apparent motion across the sky.
motion toward or away from us, revealed by Doppler shifts.
orbital motion around the Galaxy.
Answer: c
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9. Question 4 A star’s proper motion is its true motion in space.
apparent shift as we view from opposite sides of Earth’s orbit every 6 months.
annual apparent motion across the sky.
motion toward or away from us, revealed by Doppler shifts.
orbital motion around the Galaxy.
Explanation: A star’s “real space motion” combines its apparent proper motion with its radial motion toward or away from Earth.
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10. Question 5
In the stellar magnitude system invented by Hipparchus, a smaller magnitude indicates a _____ star.
brighter
hotter
cooler
fainter
more distant
Answer: a
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11. Question 5
In the stellar magnitude system invented by Hipparchus, a smaller magnitude indicates a _____ star.
brighter
hotter
cooler
fainter
more distant
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12. Question 6
A star’s apparent magnitude is a number used to describe how our eyes measure its
distance.
temperature.
brightness.
absolute luminosity.
radial velocity.
Answer: c
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13. Question 6
A star’s apparent magnitude is a number used to describe how our eyes measure its
distance.
temperature.
brightness.
absolute luminosity.
radial velocity.
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14. Question 7
The absolute magnitude of a star is its brightness as seen from a distance of
1 million kilometers.
1 astronomical unit.
1 light-year.
10 parsecs.
10 light-years.
Answer: d
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15. Question 7
The absolute magnitude of a star is its brightness as seen from a distance of
1 million kilometers.
1 astronomical unit.
1 light-year.
10 parsecs.
10 light-years.
Explanation: Astronomers use a distance of 10 parsecs (about 32 light-years) as a standard for specifying and comparing the brightnesses of stars.
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16. Question 8
Which of the following quantities do you need in order to calculate a star’s luminosity?
Apparent brightness (flux)
Doppler shift of spectral lines
Color of the star
Distance to the star
Both a and d are correct.
Answer: e
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17. Question 8
Which of the following quantities do you need in order to calculate a star’s luminosity?
Apparent brightness (flux)
Doppler shift of spectral lines
Color of the star
Distance to the star
Both a and d are correct.
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18. Question 9
What are the two most important intrinsic properties for classifying stars?
Distance and surface temperature
Luminosity and surface temperature
Distance and luminosity
Mass and age
Distance and color
Answer: b
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19. Question 9
What are the two most important intrinsic properties for classifying stars?
Distance and surface temperature
Luminosity and surface temperature
Distance and luminosity
Mass and age
Distance and color
Explanation: The H–R diagram plots stars based on their luminosities and surface temperatures.
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20. Question 10
Wien’s law tells us that the hotter an object, the _____ the peak wavelength of its emitted light.
longer
more green
heavier
shorter
more constant
Answer: d
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21. Question 10
Wien’s law tells us that the hotter an object, the _____ the peak wavelength of its emitted light.
longer
more green
heavier
shorter
more constant
Explanation: Wien’s law states that hotter stars appear more blue in color, and cooler stars appear more red in color.
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22. Question 11 We estimate the surface temperature of a star by using
its color.
the pattern of absorption lines in its spectrum.
Wien’s law.
differences in brightness as measured through red and blue filters.
All of the above are used.
Answer: e
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23. Question 11 We estimate the surface temperature of a star by using
its color.
the pattern of absorption lines in its spectrum.
Wien’s law.
differences in brightness as measured through red and blue filters.
All of the above are used.
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24. Question 12
Which spectral classification type corresponds to a star like the Sun? O A F G M
Answer: d
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25. Question 12
Which spectral classification type corresponds to a star like the Sun? O A F G M
Explanation: The OBAFGKM classification scheme is based on absorption lines.
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26. Question 13
The key difference between the spectra of B stars and G stars is
B stars show strong hydrogen lines; G stars show weaker hydrogen lines.
B stars show few metal lines; G stars show many.
B stars have no metal atoms.
G stars have no hydrogen atoms.
Both a and b are true.
Answer: a
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27. Question 13
The key difference between the spectra of B stars and G stars is
B stars show strong hydrogen lines; G stars show weaker hydrogen lines.
B stars show few metal lines; G stars show many.
B stars have no metal atoms.
G stars have no hydrogen atoms.
Both a and b are true.
Explanation: The original OBAFGKM sequence was arranged alphabetically by the strength of hydrogen absorption lines. B stars had strong hydrogen lines; G stars had weak lines.
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28. Question 14 Astronomers can estimate the size of a star using
apparent brightness.
direct observation of diameter.
temperature.
distance to the star.
a, b, and c are all true.
Answer: e
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29. Question 14 Astronomers can estimate the size of a star using
apparent brightness.
direct observation of diameter.
temperature.
distance to the star.
a, b, and c are all true.
Explanation: Brightness and temperature are used to plot the star on an H–R diagram and indicate its approximate size. Some stars are large enough to measure directly.
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30. Question 15 Eclipsing binary stars are very useful for determining the
ages of stars.
absolute luminosities of stars.
masses of stars.
distances to stars.
rotation rates of stars.
Answer: c
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31. Question 15 Eclipsing binary stars are very useful for determining the
ages of stars.
absolute luminosities of stars.
masses of stars.
distances to stars.
rotation rates of stars.
Explanation: Analysis of the light curve of an eclipsing binary star system can reveal the masses of the stars.
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32. Question 16
What is the single most important characteristic in determining the course of a star’s evolution?
Density
Absolute brightness
Distance
Surface temperature
Mass
Answer: e
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33. Question 16
What is the single most important characteristic in determining the course of a star’s evolution?
Density
Absolute brightness
Distance
Surface temperature
Mass
Explanation: A star’s mass determines how fast it forms, its luminosity on the main sequence, how long it will shine, and its ultimate fate.
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