Question 1

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

Question 2

Sirius is a star with spectral type A star and Rigel is a star with spectral type B star. What can we conclude?

Accepted Answer

A)  Rigel has a higher surface temperature than Sirius. 
B)  Rigel has a higher core temperature than Sirius. 
C)  Sirius has a higher core temperature than Rigel. 
D)  Sirius has a higher surface temperature than Rigel. 
A)  Rigel has a higher surface temperature than Sirius. 
B)  Rigel has a higher core temperature than Sirius. 
C)  Sirius has a higher core temperature than Rigel. 
D)  Sirius has a higher surface temperature than Rigel. A

Question 3

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 that are cool and dim?

Accepted Answer

A)  a 
B)  b 
C)  c 
D)  d 
E)  e 
A)  a 
B)  b 
C)  c 
D)  d 
E)  e D

Question 4

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. 
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 5

All stars are born with the same basic composition, yet stars can look quite different from one another. Which two factors primarily determine the characteristics of a star?

Accepted Answer

A)  Its mass and its stage of life 
B)  Its apparent brightness and its distance 
C)  Its age and its location in the galaxy 
D)  Its mass and its surface temperature 
E)  Its apparent brightness and its luminosity 
A)  Its mass and its stage of life 
B)  Its apparent brightness and its distance 
C)  Its age and its location in the galaxy 
D)  Its mass and its surface temperature 
E)  Its apparent brightness and its luminosity

Question 6

Two stars, Fred and Barney, are of the same size. Fred has spectral type F, while Barney has spectral type B. Which one is more luminous?

Accepted Answer

Barney has a hotter surface te

Question 7

You observe a star cluster with a main-sequence turn-off point at spectral type G2 (the same spectral type as the Sun). What is the age of this star cluster?

Accepted Answer

A)  10,000 years. 
B)  4.6 billion years. 
C)  10 billion years. 
D)  100 billion years. 
E)  You also need to know the luminosity class of the turn-off point to determine the age. 
A)  10,000 years. 
B)  4.6 billion years. 
C)  10 billion years. 
D)  100 billion years. 
E)  You also need to know the luminosity class of the turn-off point to determine the age.

Question 8

Which main sequence star will have the shortest lifetime?

Accepted Answer

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

Question 9

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 represents stars of the smallest radii?

Accepted Answer

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

Question 10

Which main sequence star has the lowest mass?

Accepted Answer

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

Question 11

Which of the following correctly states the relationship between the apparent brightness, luminosity, and distance of a star?

Accepted Answer

A)  luminosity =   
B)  apparent brightness = $ \frac{\text { luminosity }}{4 \pi \times(\text { distance })^{2}} $ 
C)  apparent brightness = luminosity × 4π × (distance) ² 
D)  distance =   
A)  luminosity =   
B)  apparent brightness = $ \frac{\text { luminosity }}{4 \pi \times(\text { distance })^{2}} $ 
C)  apparent brightness = luminosity × 4π × (distance) ² 
D)  distance =

Question 12

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

Accepted Answer

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

Question 13

On a Hertzsprung-Russell diagram, where would you find stars that have the largest radii?

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 14

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 surface temperature. 
B)  The spectral type of a star can be used to determine its color. 
C)  A star with spectral type A is cooler than a star with spectral type B. 
D)  A star with spectral type F2 is hotter than a star with spectral type F3. 
E)  All of the above are true. 
A)  The spectral type of a star can be used to determine its surface temperature. 
B)  The spectral type of a star can be used to determine its color. 
C)  A star with spectral type A is cooler than a star with spectral type B. 
D)  A star with spectral type F2 is hotter than a star with spectral type F3. 
E)  All of the above are true.

Question 15

The 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 the earth's distance from the Sun.

Accepted Answer

The Sun would appear four time

Question 16

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

Question 17

Which of the following best describes the axes of a Hertzsprung-Russell (H-R) diagram?

Accepted Answer

A)  surface temperature on the horizontal axis and luminosity on the vertical axis 
B)  mass on the horizontal axis and luminosity on the vertical axis 
C)  surface temperature on the horizontal axis and radius on the vertical axis 
D)  mass on the horizontal axis and stellar age on the vertical axis 
E)  interior temperature on the horizontal axis and mass on the vertical axis 
A)  surface temperature on the horizontal axis and luminosity on the vertical axis 
B)  mass on the horizontal axis and luminosity on the vertical axis 
C)  surface temperature on the horizontal axis and radius on the vertical axis 
D)  mass on the horizontal axis and stellar age on the vertical axis 
E)  interior temperature on the horizontal axis and mass on the vertical axis

Question 18

If the Sun-Earth separation was 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)  10 times less 
B)  About 3.16 (or the square root of 10) times less 
C)  10 times more 
D)  100 times less 
E)  100 times more 
A)  10 times less 
B)  About 3.16 (or the square root of 10) times less 
C)  10 times more 
D)  100 times less 
E)  100 times more

Question 19

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

Accepted Answer

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

Question 20

From hottest to coolest, the order of the spectral types of stars is ________.

Accepted Answer

A)  OBAFGKM 
B)  OBAGFKM 
C)  ABFGKMO 
D)  OMKGFBA 
E)  ABCDEFG 
A)  OBAFGKM 
B)  OBAGFKM 
C)  ABFGKMO 
D)  OMKGFBA 
E)  ABCDEFG

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

Sirius is a star with spectral type A star and Rigel is a star with spectral type B star. What can we conclude?

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 that are cool and dim?

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

All stars are born with the same basic composition, yet stars can look quite different from one another. Which two factors primarily determine the characteristics of a star?

Two stars, Fred and Barney, are of the same size. Fred has spectral type F, while Barney has spectral type B. Which one is more luminous?

You observe a star cluster with a main-sequence turn-off point at spectral type G2 (the same spectral type as the Sun). What is the age of this star cluster?

Which main sequence star will have the shortest lifetime?

Which main sequence star has the lowest mass?

Which of the following correctly states the relationship between the apparent brightness, luminosity, and distance of a star?

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

On a Hertzsprung-Russell diagram, where would you find stars that have the largest radii?

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

The 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 the earth's distance from the Sun.

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

Which of the following best describes the axes of a Hertzsprung-Russell (H-R) diagram?

If the Sun-Earth separation was 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?

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

From hottest to coolest, the order of the spectral types of stars is ________.

Our Place in 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 Planetary Systems: Our Solar System and Beyond

Earth and the Terrestrial Worlds

Jovian Planet Systems

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

Our Star

Star Stuff

Bizarre Stellar Graveyard

Our Galaxy

Galaxies and the Foundation of Modern Cosmology

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Life in the Universe

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Exam 11: Surveying the Stars

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

Sirius is a star with spectral type A star and Rigel is a star with spectral type B star. What can we conclude?

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 that are cool and dim?

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

All stars are born with the same basic composition, yet stars can look quite different from one another. Which two factors primarily determine the characteristics of a star?

Two stars, Fred and Barney, are of the same size. Fred has spectral type F, while Barney has spectral type B. Which one is more luminous?

You observe a star cluster with a main-sequence turn-off point at spectral type G2 (the same spectral type as the Sun). What is the age of this star cluster?

Which main sequence star will have the shortest lifetime?

Which main sequence star has the lowest mass?

Which of the following correctly states the relationship between the apparent brightness, luminosity, and distance of a star?

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

On a Hertzsprung-Russell diagram, where would you find stars that have the largest radii?

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

The 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 the earth's distance from the Sun.

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

Which of the following best describes the axes of a Hertzsprung-Russell (H-R) diagram?

If the Sun-Earth separation was 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?

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

From hottest to coolest, the order of the spectral types of stars is ________.

Our Place in 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 Planetary Systems: Our Solar System and Beyond

Earth and the Terrestrial Worlds

Jovian Planet Systems

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

Our Star

Star Stuff

Bizarre Stellar Graveyard

Our Galaxy

Galaxies and the Foundation of Modern Cosmology

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

The Beginning of Time

Life in the Universe

Filters