Question 1

Which of the following statements comparing open and globular star clusters is not true?

Accepted Answer

A)   Open and globular clusters each typically contain a few hundred stars.
B)   Open clusters are found only in the disk of the galaxy while globular clusters may be found both in the disk and the halo of the galaxy.
C)   Stars in open clusters are relatively young while stars in globular clusters are very old.
D)   For both open and globular clusters, we can assume that all the stars in a particular cluster are about the same age.

Question 2

Which star is the hottest star?

Accepted Answer

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

Question 3

The spectral sequence, in order of decreasing temperature, is

Accepted Answer

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

Question 4

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

Accepted Answer

A) True 
 B)False

Question 5

A star of spectral type G lives approximately how long on the main sequence?

Accepted Answer

A)   1,000 years
B)   10,000 years
C)   10 million years
D)   1 billion years
E)   10 billion years

Question 6

On the main sequence, stars obtain their energy

Accepted Answer

A)   from chemical reactions.
B)   from gravitational contraction.
C)   by converting hydrogen to helium.
D)   by converting helium to carbon, nitrogen, and oxygen.
E)   from nuclear fission.

Question 7

We can measure the radii of stars in eclipsing binary systems.

Accepted Answer

A) True 
 B)False

Question 8

On a Hertzsprung-Russell diagram, where would you find red giant stars?

Accepted Answer

A)   upper right
B)   lower right
C)   upper left
D)   lower left

Question 9

Ten parsecs is about ________.

Accepted Answer

A)   150 million kilometers
B)   32.6 light-years
C)   10,000 seconds
D)   10 parallax seconds of angle

Question 10

The choices below each describe the appearance of an H-R diagram for a different star cluster. Which cluster is the youngest?

Accepted Answer

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

Question 11

Which stellar spectral type has strong molecular absorption lines in its optical spectrum?

Accepted Answer

A)   O
B)   B
C)   G
D)   K
E)   M

Question 12

You see two main-sequence stars with the same spectral type. Star 1 is dimmer in apparent brightness than Star 2 by a factor of 100. What can you conclude, assuming there is no absorption of either star's light by interstellar gas or dust?

Accepted Answer

A)   Without first knowing the distances to these stars, you cannot draw any conclusions about how their true luminosities compare to each other.
B)   The luminosity of Star 1 is a factor of 100 less than the luminosity of Star 2.
C)   Star 1 is 100 times more distant than Star 2.
D)   Star 1 is 100 times nearer than Star 2.
E)   Star 1 is 10 times more distant than Star 2.

Question 13

Star A is identical to Star B, except that Star A is twice as far from us as Star B. Therefore:

Accepted Answer

A)   Both stars have the same luminosity, but the apparent brightness of Star B is four times that of Star A.
B)   Both stars have the same luminosity, but the apparent brightness of Star B is twice that of Star A.
C)   Both stars have the same apparent brightness, but the luminosity of Star B is four times that of Star A.
D)   Both stars have the same luminosity, but the apparent brightness of Star A is four times that of Star B.

Question 14

The axes on a Hertzsprung-Russell (H-R)  diagram represent ________.

Accepted Answer

A)   luminosity and surface temperature
B)   mass and luminosity
C)   luminosity and apparent brightness
D)   mass and radius

Question 15

If the distance between us and a star is doubled, with everything else remaining the same, its luminosity

Accepted Answer

A)   is decreased by a factor of four, and its apparent brightness is decreased by a factor of four.
B)   is decreased by a factor of two, and its apparent brightness is decreased by a factor of two.
C)   remains the same, but its apparent brightness is decreased by a factor of two.
D)   remains the same, but its apparent brightness is decreased by a factor of four.
E)   is decreased by a factor of four, but its apparent brightness remains the same.

Question 16

A scientist claims that all red main sequence stars are 1 billion years old. Which of the following, if true, would prove that this claim is false?

Accepted Answer

A)   The discovery of a red main sequence star in a star cluster where all the other stars are red giants or red supergiants.
B)   Stellar evolution theory predicts that the main sequence lifetime of red stars can be as long as 100 billion years.
C)   The minimum lifespan of a red main sequence star is estimated to be 10 billion years.
D)   The discovery of a red main sequence star in a star cluster where the main sequence turnoff is about that of the Sun.

Question 17

If a star has a mass of 10 solar masses and a luminosity of 10,000 solar luminosities, how long is its lifetime? (The Sun's lifetime is 10 billion years.)

Accepted Answer

A)   10 million years
B)   1 million years
C)   100 trillion years
D)   100 billion years

Question 18

Most stars on the main sequence fuse hydrogen into helium in their cores, but some do not.

Accepted Answer

A) True 
 B)False

Question 19

A 10 solar mass star is about ten times more luminous than a 1 solar mass star.

Accepted Answer

A) True 
 B)False

Question 20

The following questions refer to the sketch of the H-R diagram below. Choose the best answer in each case. Note that choice (a) refers to the entire main sequence, while (c) and (d) refer to only small parts of the main sequence. If choice (c) or (d) offers a better answer to a particular question than (a) , use the best choice. You may use the same choice more than once.

-Which group includes the Sun?

Accepted Answer

The answer of The following questions refer to the sketch...

Exam 11: Surveying the Stars

Which stellar spectral type has strong molecular absorption lines in its optical spectrum?

Correct Answer
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Which star is the hottest star?

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 the youngest?

Correct Answer
verified

A star of spectral type G lives approximately how long on the main sequence?

Correct Answer
verified

If a star has a mass of 10 solar masses and a luminosity of 10,000 solar luminosities, how long is its lifetime? (The Sun's lifetime is 10 billion years.)

Correct Answer
verified

If the distance between us and a star is doubled, with everything else remaining the same, its luminosity

Correct Answer
verified

We can measure the radii of stars in eclipsing binary systems.

Correct Answer
verified

Which of the following statements comparing open and globular star clusters is not true?

Correct Answer
verified

A 10 solar mass star is about ten times more luminous than a 1 solar mass star.

Correct Answer
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Correct Answer
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The axes on a Hertzsprung-Russell (H-R) diagram represent ________.

Correct Answer
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Most stars on the main sequence fuse hydrogen into helium in their cores, but some do not.

Correct Answer
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Two stars have the same luminosity. Star X is spectral type F, while Star Y is spectral type K. Star X must be larger in radius than Star Y.

Correct Answer
verified

On a Hertzsprung-Russell diagram, where would you find red giant stars?

Correct Answer
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You see two main-sequence stars with the same spectral type. Star 1 is dimmer in apparent brightness than Star 2 by a factor of 100. What can you conclude, assuming there is no absorption of either star's light by interstellar gas or dust?

Correct Answer
verified

Ten parsecs is about ________.

Correct Answer
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Star A is identical to Star B, except that Star A is twice as far from us as Star B. Therefore:

Correct Answer
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On the main sequence, stars obtain their energy

Correct Answer
verified

A scientist claims that all red main sequence stars are 1 billion years old. Which of the following, if true, would prove that this claim is false?

Correct Answer
verified

The spectral sequence, in order of decreasing temperature, is

Correct Answer
verified

Exam 11: Surveying the Stars

Which stellar spectral type has strong molecular absorption lines in its optical spectrum?

Correct AnswerverifiedShow Answer

Which star is the hottest star?

Correct AnswerverifiedShow Answer

The choices below each describe the appearance of an H-R diagram for a different star cluster. Which cluster is the youngest?

Correct AnswerverifiedShow Answer

A star of spectral type G lives approximately how long on the main sequence?

Correct AnswerverifiedShow Answer

If a star has a mass of 10 solar masses and a luminosity of 10,000 solar luminosities, how long is its lifetime? (The Sun's lifetime is 10 billion years.)

Correct AnswerverifiedShow Answer

If the distance between us and a star is doubled, with everything else remaining the same, its luminosity

Correct AnswerverifiedShow Answer

We can measure the radii of stars in eclipsing binary systems.

Correct AnswerverifiedShow Answer

Which of the following statements comparing open and globular star clusters is not true?

Correct AnswerverifiedShow Answer

A 10 solar mass star is about ten times more luminous than a 1 solar mass star.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

The axes on a Hertzsprung-Russell (H-R) diagram represent ________.

Correct AnswerverifiedShow Answer

Most stars on the main sequence fuse hydrogen into helium in their cores, but some do not.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

On a Hertzsprung-Russell diagram, where would you find red giant stars?

Correct AnswerverifiedShow Answer

You see two main-sequence stars with the same spectral type. Star 1 is dimmer in apparent brightness than Star 2 by a factor of 100. What can you conclude, assuming there is no absorption of either star's light by interstellar gas or dust?

Correct AnswerverifiedShow Answer

Ten parsecs is about ________.

Correct AnswerverifiedShow Answer

Star A is identical to Star B, except that Star A is twice as far from us as Star B. Therefore:

Correct AnswerverifiedShow Answer

On the main sequence, stars obtain their energy

Correct AnswerverifiedShow Answer

A scientist claims that all red main sequence stars are 1 billion years old. Which of the following, if true, would prove that this claim is false?

Correct AnswerverifiedShow Answer

The spectral sequence, in order of decreasing temperature, is

Correct AnswerverifiedShow Answer

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