Question 1

Which main- sequence star has the lowest mass?

Accepted Answer

A)  M
B)  A
C)  O
D)  G
E)  Can't tell from information provided.F) A) and D)
G) C) and D)

Question 2

If the Sun- Earth separation were 10 AU instead of 1 AU, what would the flux of sunlight (energy per second per square meter) be at the Earth, compared to what it is today?

Accepted Answer

A)  100 times more
B)  10 times less
C)  100 times less
D)  10 times more
E)  about 3.16 (or the square root of 10) times lessF) A) and E)
G) A) and D)

Question 3

Astronomers can measure a star's mass in only certain cases. Which one of the following cases might allow astronomers to measure a star's mass?

Accepted Answer

A)  We know the star's luminosity and distance.
B)  The star is of spectral type G.
C)  The star is of spectral type A.
D)  The star is a member of a binary star system.E) None of the above
F) B) and C)

Question 4

On a Hertzsprung- Russell diagram, where would you find stars that are cool and dim?

Accepted Answer

A)  upper right
B)  lower right
C)  upper left
D)  lower leftE) A) and C)
F) A) and D)

Question 5

A star with a parallax angle of 1/20 arcsecond is .

Accepted Answer

A)  20 parsecs away
B)  10 parsecs away
C)  20 light- years away
D)  1/20 parsec awayE) B) and D)
F) C) and D)

Question 6

Which of the following stars are brightest at ultraviolet wavelengths?

Accepted Answer

A)  M stars
B)  G and K stars
C)  A and F stars
D)  O and B stars
E)  None; all stars are brightest at optical wavelengths.F) A) and E)
G) B) and E)

Question 7

Our Sun, An Average Star: Often in science it is helpful to talk about a representative example of the objects or phenomena being studied. However, you must always keep in mind that the average case is not always representative. For example, our Sun is often described as an "average" star in the Milky Way. In what sense is this statement true? In what sense is this statement seriously misleading? Do you think it is useful to characterize the stars in the Milky Way by simply citing our "average" Sun?

Accepted Answer

The statement that our Sun is an "averag...

Question 8

Which of the following statements about spectral types of stars is true?

Accepted Answer

A)  The spectral type of a star can be used to determine its color.
B)  A star with spectral type A is cooler than a star with spectral type B.
C)  A star with spectral type F2 is hotter than a star with spectral type F3.
D)  The spectral type of a star can be used to determine its surface temperature.
E)  All of the above are true.F) None of the above
G) C) and D)

Question 9

Some 10 solar mass main- sequence stars have much shorter lifetimes than other 10 solar mass main- sequence stars.

Accepted Answer

A) True 
 B)False

Question 10

Which of the following statements about spectral types of stars is not generally true?

Accepted Answer

A)  The spectral type of a star can be used to determine its distance.
B)  The spectral type of a star can be used to determine its color.
C)  The spectral type of a star can be used to determine its surface temperature.
D)  The spectral type of a star can be determined by identifying lines in its spectrum.E) A) and C)
F) B) and D)

Question 11

Based on the definition of apparent brightness, which units are appropriate for its measurement?

Accepted Answer

A)  Watts per square meter
B)  Watts
C)  Newtons
D)  JoulesE) B) and C)
F) A) and B)

Question 12

To calculate the masses of stars in a binary system, we must measure their .

Accepted Answer

A)  orbital period and average orbital distance
B)  luminosities and distance from Earth
C)  absolute magnitudes and luminosities
D)  spectral types and distance from EarthE) B) and C)
F) B) and D)

Question 13

The stellar spectral sequence, in order of decreasing temperature, is

Accepted Answer

A)  OBAGFKM.
B)  OFBAGKM.
C)  OBAFGKM.
D)  BAGFKMO.
E)  ABFGKMO.F) A) and E)
G) C) and E)

Question 14

How is the lifetime of a star related to its mass?

Accepted Answer

A)  More massive stars live much shorter lives than less massive stars.
B)  More massive stars live slightly longer lives than less massive stars.
C)  More massive stars live slightly shorter lives than less massive stars.
D)  More massive stars live much longer lives than less massive stars.E) B) and C)
F) A) and D)

Question 15

Since all stars begin their lives with the same basic composition, what characteristic most determines how they will differ?

Accepted Answer

A)  location where they are formed
B)  color they are formed with
C)  luminosity they are formed with
D)  time they are formed
E)  mass they are formed withF) C) and D)
G) None of the above

Question 16

What are the standard units for luminosity?

Accepted Answer

A)  kilograms
B)  Watts
C)  Watts per second
D)  Joules
E)  NewtonsF) C) and D)
G) B) and D)

Question 17

You observe a star and you want to plot it on an H- R diagram. You will need to measure all of the following, except the star's .

Accepted Answer

A)  mass
B)  apparent brightness
C)  distance
D)  spectral typeE) None of the above
F) A) and B)

Question 18

An O- star has a hotter surface temperature than the Sun. Therefore, compared to the Sun,

Accepted Answer

A)  it emits at about the same wavelengths as the Sun (similar peak) but it is much fainter.
B)  its emission peaks in the infrared part of the spectrum.
C)  it emits at about the same wavelengths as the Sun (similar peak) but it is much brighter.
D)  its emission peaks in the blue part of the spectrum.E) B) and C)
F) A) and D)

Question 19

What can we infer, at least roughly, from a star's luminosity class?

Accepted Answer

A)  its mass
B)  its size (radius) 
C)  its age in years
D)  its surface temperatureE) A) and B)
F) B) and C)

Question 20

The choices below each describe the appearance of an H- R diagram for a different star cluster. Which cluster is most likely to be located in the halo of our galaxy?

Accepted Answer

A)  The diagram shows main- sequence stars of all the spectral types except O and B, along with a few giants and supergiants.
B)  The diagram shows no main- sequence stars at all, but it has numerous supergiants and white dwarfs.
C)  The diagram shows main- sequence stars of spectral types G, K, and M, along with numerous giants and white dwarfs.
D)  The diagram shows main- sequence stars of every spectral type except O, along with a few giants and supergiants.E) A) and B)
F) A) and C)

Exam 12: Surveying the Stars

The stellar spectral sequence, in order of decreasing temperature, is

Correct Answer
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The choices below each describe the appearance of an H- R diagram for a different star cluster. Which cluster is most likely to be located in the halo of our galaxy?

Correct Answer
verified

What are the standard units for luminosity?

Correct Answer
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Which of the following statements about spectral types of stars is not generally true?

Correct Answer
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To calculate the masses of stars in a binary system, we must measure their .

Correct Answer
verified

Based on the definition of apparent brightness, which units are appropriate for its measurement?

Correct Answer
verified

Which of the following statements about spectral types of stars is true?

Correct Answer
verified

A star with a parallax angle of 1/20 arcsecond is .

Correct Answer
verified

You observe a star and you want to plot it on an H- R diagram. You will need to measure all of the following, except the star's .

Correct Answer
verified

Which main- sequence star has the lowest mass?

Correct Answer
verified

Which of the following stars are brightest at ultraviolet wavelengths?

Correct Answer
verified

If the Sun- Earth separation were 10 AU instead of 1 AU, what would the flux of sunlight (energy per second per square meter) be at the Earth, compared to what it is today?

Correct Answer
verified

What can we infer, at least roughly, from a star's luminosity class?

Correct Answer
verified

Correct Answer
Answered by ExamLex AI
The statement that our Sun is an "averag...
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An O- star has a hotter surface temperature than the Sun. Therefore, compared to the Sun,

Correct Answer
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Astronomers can measure a star's mass in only certain cases. Which one of the following cases might allow astronomers to measure a star's mass?

Correct Answer
verified

Since all stars begin their lives with the same basic composition, what characteristic most determines how they will differ?

Correct Answer
verified

On a Hertzsprung- Russell diagram, where would you find stars that are cool and dim?

Correct Answer
verified

Some 10 solar mass main- sequence stars have much shorter lifetimes than other 10 solar mass main- sequence stars.

Correct Answer
verified

How is the lifetime of a star related to its mass?

Correct Answer
verified

Exam 12: Surveying the Stars

The stellar spectral sequence, in order of decreasing temperature, is

Correct AnswerverifiedShow Answer

The choices below each describe the appearance of an H- R diagram for a different star cluster. Which cluster is most likely to be located in the halo of our galaxy?

Correct AnswerverifiedShow Answer

What are the standard units for luminosity?

Correct AnswerverifiedShow Answer

Which of the following statements about spectral types of stars is not generally true?

Correct AnswerverifiedShow Answer

To calculate the masses of stars in a binary system, we must measure their .

Correct AnswerverifiedShow Answer

Based on the definition of apparent brightness, which units are appropriate for its measurement?

Correct AnswerverifiedShow Answer

Which of the following statements about spectral types of stars is true?

Correct AnswerverifiedShow Answer

A star with a parallax angle of 1/20 arcsecond is .

Correct AnswerverifiedShow Answer

You observe a star and you want to plot it on an H- R diagram. You will need to measure all of the following, except the star's .

Correct AnswerverifiedShow Answer

Which main- sequence star has the lowest mass?

Correct AnswerverifiedShow Answer

Which of the following stars are brightest at ultraviolet wavelengths?

Correct AnswerverifiedShow Answer

If the Sun- Earth separation were 10 AU instead of 1 AU, what would the flux of sunlight (energy per second per square meter) be at the Earth, compared to what it is today?

Correct AnswerverifiedShow Answer

What can we infer, at least roughly, from a star's luminosity class?

Correct AnswerverifiedShow Answer

Correct AnswerAnswered by ExamLex AIThe statement that our Sun is an "averag...View AnswerShow Answer

An O- star has a hotter surface temperature than the Sun. Therefore, compared to the Sun,

Correct AnswerverifiedShow Answer

Astronomers can measure a star's mass in only certain cases. Which one of the following cases might allow astronomers to measure a star's mass?

Correct AnswerverifiedShow Answer

Since all stars begin their lives with the same basic composition, what characteristic most determines how they will differ?

Correct AnswerverifiedShow Answer

On a Hertzsprung- Russell diagram, where would you find stars that are cool and dim?

Correct AnswerverifiedShow Answer

Some 10 solar mass main- sequence stars have much shorter lifetimes than other 10 solar mass main- sequence stars.

Correct AnswerverifiedShow Answer

How is the lifetime of a star related to its mass?

Correct AnswerverifiedShow Answer

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
verified

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
verified

Correct Answer
Answered by ExamLex AI
The statement that our Sun is an "averag...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified