Question 1

Earth is about 150 million km from the Sun,and the apparent brightness of the Sun in our sky is about 1,300 watts per square meter.Determine the apparent brightness we would measure for the Sun if we were located half Earth's distance from the Sun.

Accepted Answer

The Sun would appear four time...

Question 2

We can measure the radii of stars in an eclipsing binary system,in addition to the masses.

Accepted Answer

A) True 
 B)False  True

Question 3

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

Question 4

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

Accepted Answer

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

Question 5

Which of the following statements about apparent and absolute magnitudes is true?

Accepted Answer

A)  The magnitude system that we use now is based on a system used by the ancient Greeks over 2,000 years ago that classified stars by how bright they appeared.
B)  A star with apparent magnitude 1 is brighter than one with apparent magnitude 2.
C)  The absolute magnitude of a star is another measure of its luminosity.
D)  A star's absolute magnitude is the apparent magnitude it would have if it were at a distance of 10 parsecs from Earth.
E)  All of the above are true.

Question 6

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

Accepted Answer

A) True 
 B)False

Question 7

According to the inverse square law of light,how will the apparent brightness of an object change if its distance to us triples?

Accepted Answer

A)  Its apparent brightness will increase by a factor of 9.
B)  Its apparent brightness will decrease by a factor of 9.
C)  Its apparent brightness will increase by a factor of 3.
D)  Its apparent brightness will decrease by a factor of 3.

Question 8

Suppose our Sun were suddenly replaced by a supergiant star.Which of the following would be true?

Accepted Answer

A)  Earth would be inside the supergiant.
B)  The supergiant's surface temperature would be much hotter than the surface temperature of our Sun.
C)  Earth would fly off into interstellar space.
D)  The supergiant would appear as large as the full Moon in our sky.

Question 9

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

Accepted Answer

A)  by using computer models of hydrogen fusion and stellar structure
B)  by measuring stellar radii with very powerful telescopes
C)  by comparing stars with the same spectral type but different luminosities
D)  by measuring the masses and spectral types of main-sequence stars in binary systems

Question 10

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

Accepted Answer

A) True 
 B)False

Question 11

Refer to the choices in the table for the following questions.
 
-Which star appears brightest in the sky?

Accepted Answer

C

Question 12

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 with

Question 13

Which cluster is 10 billion years old?

Accepted Answer

A)   
B)   
C)   
D)

Question 14

The spectral sequence sorts stars according to

Accepted Answer

A)  mass.
B)  surface temperature.
C)  luminosity.
D)  core temperature.
E)  radius.

Question 15

Refer to the choices in the table for the following questions.
 
-Which star is most similar to the Sun?

Accepted Answer

The answer of Refer to the choices in the table...

Question 16

Star A has an apparent magnitude of 3 and Star B has an apparent magnitude of 5.Which star is brighter in our sky?

Accepted Answer

A)  Star A
B)  Star B
C)  The two stars have the same brightness in our sky,but Star A is closer to us than Star B.
D)  There is not enough information to answer the question.

Question 17

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

Accepted Answer

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

Question 18

The following questions refer to the sketch of the H-R diagram below.Please choose the best answer in each case,i.e. ,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 represents hydrogen-burning stars with the shortest lifetimes?

Accepted Answer

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

Question 19

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)  The star is a member of a binary star system.
B)  The star is of spectral type G.
C)  The star is of spectral type A.
D)  We know the star's luminosity and distance.

Question 20

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

Accepted Answer

A) True 
 B)False  False

Exam 15: Surveying the Stars

Earth is about 150 million km from the Sun,and the apparent brightness of the Sun in our sky is about 1,300 watts per square meter.Determine the apparent brightness we would measure for the Sun if we were located half Earth's distance from the Sun.

Correct Answer
verified
The Sun would appear four time...
View Answer

We can measure the radii of stars in an eclipsing binary system,in addition to the masses.

Correct Answer
verified
True

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

Correct Answer
verified

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

Correct Answer
verified

Which of the following statements about apparent and absolute magnitudes is true?

Correct Answer
verified

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

Correct Answer
verified

According to the inverse square law of light,how will the apparent brightness of an object change if its distance to us triples?

Correct Answer
verified

Suppose our Sun were suddenly replaced by a supergiant star.Which of the following would be true?

Correct Answer
verified

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

Correct Answer
verified

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

Correct Answer
verified

Refer to the choices in the table for the following questions. -Which star appears brightest in the sky?

Correct Answer
verified
C

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

Correct Answer
verified

Which cluster is 10 billion years old?

Correct Answer
verified

The spectral sequence sorts stars according to

Correct Answer
verified

Refer to the choices in the table for the following questions. -Which star is most similar to the Sun?

Correct Answer
verified

Star A has an apparent magnitude of 3 and Star B has an apparent magnitude of 5.Which star is brighter in our sky?

Correct Answer
verified

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

Correct Answer
verified

Correct Answer
verified

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

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

Correct Answer
verified
False

Exam 15: Surveying the Stars

Earth is about 150 million km from the Sun,and the apparent brightness of the Sun in our sky is about 1,300 watts per square meter.Determine the apparent brightness we would measure for the Sun if we were located half Earth's distance from the Sun.

Correct AnswerverifiedThe Sun would appear four time...View AnswerShow Answer

We can measure the radii of stars in an eclipsing binary system,in addition to the masses.

Correct AnswerverifiedTrue

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

Correct AnswerverifiedShow Answer

Which of the following statements about apparent and absolute magnitudes is true?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

According to the inverse square law of light,how will the apparent brightness of an object change if its distance to us triples?

Correct AnswerverifiedShow Answer

Suppose our Sun were suddenly replaced by a supergiant star.Which of the following would be true?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Refer to the choices in the table for the following questions. -Which star appears brightest in the sky?

Correct AnswerverifiedC

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

Correct AnswerverifiedShow Answer

Which cluster is 10 billion years old?

Correct AnswerverifiedShow Answer

The spectral sequence sorts stars according to

Correct AnswerverifiedShow Answer

Refer to the choices in the table for the following questions. -Which star is most similar to the Sun?

Correct AnswerverifiedShow Answer

Star A has an apparent magnitude of 3 and Star B has an apparent magnitude of 5.Which star is brighter in our sky?

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

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

Correct AnswerverifiedFalse

Correct Answer
verified
The Sun would appear four time...
View Answer

Correct Answer
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True

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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Correct Answer
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C

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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False