Question 1

How did astronomers discover the relationship between spectral type and mass for main sequence stars?

Accepted Answer

A)   By measuring the masses and spectral types of main-sequence stars in binary systems
B)   By using computer models of hydrogen fusion and stellar structure
C)   By measuring stellar radii with very powerful telescopes
D)   By comparing stars with the same spectral type but different luminositiesE) None of the above
F) A) and C)

Question 2

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)   time they are formed
C)   luminosity they are formed with
D)   mass they are formed with
E)   color they are formed withF) A) and E)
G) C) and E)

Question 3

The apparent brightness of a star depends only on its luminosity.

Accepted Answer

A) True 
 B)False

Question 4

If the distance between us and a star is doubled, its apparent brightness will decrease by a factor of four.

Accepted Answer

A) True 
 B)False

Question 5

It is impossible for a star to have a negative apparent magnitude, such as -1.

Accepted Answer

A) True 
 B)False

Question 6

On a Hertzsprung-Russell diagram, where on the main sequence would you find stars that have the greatest mass?

Accepted Answer

A)   upper right
B)   lower right
C)   upper left
D)   lower leftE) C) and D)
F) None of the above

Question 7

On an H-R diagram, stellar masses ________.

Accepted Answer

A)   can be determined for main sequence stars but not for other types of stars
B)   are greatest in the lower left and least in the upper right
C)   decrease from upper left to lower right
D)   are impossible to determineE) C) and D)
F) B) and D)

Question 8

What are the standard units for apparent brightness?

Accepted Answer

A)   Watts
B)   Joules
C)   Newtons
D)   Watts per second
E)   Watts per square meterF) None of the above
G) A) and D)

Question 9

Which of the following stars has a spectrum that peaks at the highest frequency?

Accepted Answer

A)   A yellow star
B)   A red star
C)   A blue starD) A) and C)
E) All of the above

Question 10

Which of the following terms is given to a pair of stars that appear to change position in the sky, indicating that they are orbiting one another?

Accepted Answer

A)   visual binary
B)   eclipsing binary
C)   spectroscopic binary
D)   double star
E)   none of the aboveF) A) and B)
G) A) and C)

Question 11

A star's luminosity is the

Accepted Answer

A)   apparent brightness of the star in our sky.
B)   surface temperature of the star.
C)   lifetime of the star.
D)   total amount of energy that the star will radiate over its entire lifetime.
E)   total amount of energy that the star radiates each second.F) B) and D)
G) C) and D)

Question 12

Two stars, Tom and Jerry, have the same spectral type. Tom is luminosity class V and Jerry is luminosity class I. Which star is bigger? Which star is more luminous? Which star has a hotter surface temperature? Explain your answers.

Accepted Answer

Tom is on the main sequence, while Jerry...

Question 13

Observing Stellar Evolution: Stars evolve on timescales of millions to billions of years, making it impossible for astronomers to follow the life-cycle of any individual star. Explain how astronomers overcome this limitation. Be sure to discuss the important role that observations of star clusters play in revealing the evolution of stars.

Accepted Answer

Astronomers overcome the limitation of n...

Question 14

What do we mean by the main-sequence turnoff point of a star cluster, and what does it tell us?

Accepted Answer

A)   It is the spectral type of the hottest main sequence star in a star cluster, and it tells us the cluster's age.
B)   It is the point in a star cluster beyond which main sequence stars are not found, and it tells us the cluster's distance.
C)   It is the luminosity class of the largest star in a star cluster, and it tells us the cluster's age.
D)   It is the mass of the most massive star in the star cluster, and it tells us the cluster's size.E) C) and D)
F) B) and C)

Question 15

What is the approximate chemical composition (by mass)  with which all stars are born?

Accepted Answer

A)   Three quarters hydrogen, one quarter helium, no more than 2% heavier elements
B)   Half hydrogen and half helium
C)   98% hydrogen, 2% helium
D)   95% hydrogen, 4% helium, no more than 1% heavier elementsE) A) and D)
F) None of the above

Question 16

The sketch above shows groups of stars on the H-R diagram, labeled (a)  through (e) ; note that (a)  represents the entire main sequence while (c)  and (d)  represent only small parts of the main sequence. Which group represents stars fusing hydrogen in their cores?

Accepted Answer

A)   a
B)   b
C)   c
D)   d
E)   eF) A) and B)
G) C) and E)

Question 17

What is a white dwarf?

Accepted Answer

A)   The remains of a star that ran out of fuel for nuclear fusion
B)   A main sequence star of spectral type F, which tends to look white in color
C)   It is a type of star that produces energy by gravitational contraction.
D)   It is a star that follows a period-luminosity relation.E) A) and C)
F) A) and B)

Question 18

Two stars have the same spectral type. Star X is in luminosity class III, while Star Y is in luminosity class V. Star X must be larger in radius than Star Y.

Accepted Answer

A) True 
 B)False

Question 19

All stars spend approximately the same amount of time on the main sequence.

Accepted Answer

A) True 
 B)False

Question 20

The following questions refer to the representations below of H-R diagrams for different clusters of stars. In each diagram, the dotted lines locate the position of the Sun.
-Which cluster is the oldest?

Accepted Answer

A)  
B)  
C)  
D)  E) C) and D)
F) A) and C)

Exam 11: Surveying the Stars

On an H-R diagram, stellar masses ________.

Correct Answer
verified

How did astronomers discover the relationship between spectral type and mass for main sequence stars?

Correct Answer
verified

If the distance between us and a star is doubled, its apparent brightness will decrease by a factor of four.

Correct Answer
verified

Which of the following terms is given to a pair of stars that appear to change position in the sky, indicating that they are orbiting one another?

Correct Answer
verified

Two stars have the same spectral type. Star X is in luminosity class III, while Star Y is in luminosity class V. Star X must be larger in radius than Star Y.

Correct Answer
verified

On a Hertzsprung-Russell diagram, where on the main sequence would you find stars that have the greatest mass?

Correct Answer
verified

It is impossible for a star to have a negative apparent magnitude, such as -1.

Correct Answer
verified

Two stars, Tom and Jerry, have the same spectral type. Tom is luminosity class V and Jerry is luminosity class I. Which star is bigger? Which star is more luminous? Which star has a hotter surface temperature? Explain your answers.

Correct Answer
verified
Tom is on the main sequence, while Jerry...
View Answer

Correct Answer
Answered by ExamLex AI
Astronomers overcome the limitation of n...
View Answer

All stars spend approximately the same amount of time on the main sequence.

Correct Answer
verified

What is a white dwarf?

Correct Answer
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Which of the following stars has a spectrum that peaks at the highest frequency?

Correct Answer
verified

The sketch above shows groups of stars on the H-R diagram, labeled (a) through (e) ; note that (a) represents the entire main sequence while (c) and (d) represent only small parts of the main sequence. Which group represents stars fusing hydrogen in their cores?

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

What do we mean by the main-sequence turnoff point of a star cluster, and what does it tell us?

Correct Answer
verified

What is the approximate chemical composition (by mass) with which all stars are born?

Correct Answer
verified

What are the standard units for apparent brightness?

Correct Answer
verified

The following questions refer to the representations below of H-R diagrams for different clusters of stars. In each diagram, the dotted lines locate the position of the Sun. -Which cluster is the oldest?

Correct Answer
verified

The apparent brightness of a star depends only on its luminosity.

Correct Answer
verified

A star's luminosity is the

Correct Answer
verified

Exam 11: Surveying the Stars

On an H-R diagram, stellar masses ________.

Correct AnswerverifiedShow Answer

How did astronomers discover the relationship between spectral type and mass for main sequence stars?

Correct AnswerverifiedShow Answer

If the distance between us and a star is doubled, its apparent brightness will decrease by a factor of four.

Correct AnswerverifiedShow Answer

Which of the following terms is given to a pair of stars that appear to change position in the sky, indicating that they are orbiting one another?

Correct AnswerverifiedShow Answer

Two stars have the same spectral type. Star X is in luminosity class III, while Star Y is in luminosity class V. Star X must be larger in radius than Star Y.

Correct AnswerverifiedShow Answer

On a Hertzsprung-Russell diagram, where on the main sequence would you find stars that have the greatest mass?

Correct AnswerverifiedShow Answer

It is impossible for a star to have a negative apparent magnitude, such as -1.

Correct AnswerverifiedShow Answer

Two stars, Tom and Jerry, have the same spectral type. Tom is luminosity class V and Jerry is luminosity class I. Which star is bigger? Which star is more luminous? Which star has a hotter surface temperature? Explain your answers.

Correct AnswerverifiedTom is on the main sequence, while Jerry...View AnswerShow Answer

Correct AnswerAnswered by ExamLex AIAstronomers overcome the limitation of n...View AnswerShow Answer

All stars spend approximately the same amount of time on the main sequence.

Correct AnswerverifiedShow Answer

What is a white dwarf?

Correct AnswerverifiedShow Answer

Which of the following stars has a spectrum that peaks at the highest frequency?

Correct AnswerverifiedShow Answer

The sketch above shows groups of stars on the H-R diagram, labeled (a) through (e) ; note that (a) represents the entire main sequence while (c) and (d) represent only small parts of the main sequence. Which group represents stars fusing hydrogen in their cores?

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

What do we mean by the main-sequence turnoff point of a star cluster, and what does it tell us?

Correct AnswerverifiedShow Answer

What is the approximate chemical composition (by mass) with which all stars are born?

Correct AnswerverifiedShow Answer

What are the standard units for apparent brightness?

Correct AnswerverifiedShow Answer

The following questions refer to the representations below of H-R diagrams for different clusters of stars. In each diagram, the dotted lines locate the position of the Sun. -Which cluster is the oldest?

Correct AnswerverifiedShow Answer

The apparent brightness of a star depends only on its luminosity.

Correct AnswerverifiedShow Answer

A star's luminosity is the

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
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Correct Answer
verified

Correct Answer
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Correct Answer
verified
Tom is on the main sequence, while Jerry...
View Answer

Correct Answer
Answered by ExamLex AI
Astronomers overcome the limitation of n...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

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
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Correct Answer
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Correct Answer
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