Question 1

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

Question 2

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. 
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.

Question 3

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. 
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.

Question 4

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. 
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.

Question 5

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. 
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.

Question 6

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) Joules 
A) Watts per square meter 
B) Watts 
C) Newtons 
D) Joules

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. 
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.

Question 9

What are the standard units for luminosity?

Accepted Answer

A) kilograms 
B) Watts 
C) Watts per second 
D) Joules 
E) Newtons 
A) kilograms 
B) Watts 
C) Watts per second 
D) Joules 
E) Newtons

Question 10

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 type 
A) mass 
B) apparent brightness 
C) distance 
D) spectral type

Question 11

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

Question 12

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. 
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.

Question 13

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 temperature 
A) its mass 
B) its size (radius) 
C) its age in years 
D) its surface temperature

Question 14

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. 
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.

Question 15

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

Question 16

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 with 
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 with

Question 17

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

Question 18

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 19

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 less 
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 less

Question 20

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

Accepted Answer

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

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

Which of the following stars are brightest at ultraviolet wavelengths?

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

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

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?

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

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

What are the standard units for luminosity?

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 .

Which main- sequence star has the lowest mass?

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?

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

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

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

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

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

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

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?

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

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Exam 12: Surveying the Stars

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

Which of the following stars are brightest at ultraviolet wavelengths?

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

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

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?

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

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

What are the standard units for luminosity?

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 .

Which main- sequence star has the lowest mass?

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?

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

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

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

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

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

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

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?

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

A Modern View of the Universe

Discovering the Universe for Yourself

The Science of Astronomy

Making Sense of the Universe: Understanding Motion, Energy, and Gravity

Light: the Cosmic Messenger

Formation of the Solar System

Earth and the Terrestrial Worlds

Jovian Planet System

Asteroids, Comets, and Dwarf Planets: Their Nature, Orbits, and Impacts

Other Planetary Systems: the New Science of Distant Worlds

Our Star

Star Stuff

The Bizarre Stellar Graveyard

Our Galaxy

A Universe of Galaxies

The Birth of the Universe

Dark Matter, Dark Energy, and the Fate of the Universe

Life in the Universe

Filters