Question 1

The spectral sequence sorts stars according to

Accepted Answer

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

Question 2

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 an apparent magnitude of 1 appears brighter than a star with an apparent magnitude of 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. 
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 an apparent magnitude of 1 appears brighter than a star with an apparent magnitude of 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 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 have no ongoing nuclear fusion?

Accepted Answer

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

Question 4

The approximate main-sequence lifetime of a star of spectral type O is ________.

Accepted Answer

A)  3 million years 
B)  10,000 years 
C)  300 million years 
D)  10 billion years 
A)  3 million years 
B)  10,000 years 
C)  300 million years 
D)  10 billion years

Question 5

On an H-R diagram, stellar radii ________.

Accepted Answer

A)  increase diagonally from the lower left to the upper right 
B)  are greatest in the lower left and least in the upper right 
C)  decrease from left to right 
D)  are impossible to determine 
A)  increase diagonally from the lower left to the upper right 
B)  are greatest in the lower left and least in the upper right 
C)  decrease from left to right 
D)  are impossible to determine

Question 6

Confusing Terminology in Science: Scientists' love of jargon and acronyms often confounds the public and makes it impossible for them to read scientific literature. Use the example of spectral types introduced in this chapter (i.e. the Sun is a "G2" star) as a case study in jargon. What is the historical origin of the spectral types? Why are the letters in a confusing, non-alphabetical order? Why do you think astronomers persist in using spectral types? Do you think astronomers should drop this notation, and, if so, what should replace it?

Accepted Answer

The answer of Confusing Terminology in Science: Scientists' love of...

Question 7

Which of the following comparisons between low-mass stars and high-mass stars is true?

Accepted Answer

A)  Low-mass stars are cooler and less luminous than high-mass stars. 
B)  Low-mass stars are hotter and more luminous than high-mass stars. 
C)  Low-mass stars are cooler but more luminous than high-mass stars. 
D)  Low-mass stars are hotter but less luminous than high-mass stars. 
E)  Low-mass stars have the same temperature and luminosity as high-mass stars. 
A)  Low-mass stars are cooler and less luminous than high-mass stars. 
B)  Low-mass stars are hotter and more luminous than high-mass stars. 
C)  Low-mass stars are cooler but more luminous than high-mass stars. 
D)  Low-mass stars are hotter but less luminous than high-mass stars. 
E)  Low-mass stars have the same temperature and luminosity as high-mass stars.

Question 8

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

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 9

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 five times the earth's distance from the Sun.

Accepted Answer

The Sun would appear 1/25 time

Question 10

Two stars, Betty and Wilma, are both on the main sequence. Betty is more luminous than Wilma. Which one has a hotter surface temperature? Which one is more massive? Which one is bigger? If they both formed at the same time, which one will evolve off the main sequence first?

Accepted Answer

Since they are both on the main sequence

Question 11

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

Accepted Answer

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

Question 12

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 the most common type of stars?

Accepted Answer

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

Question 13

The faintest visible stars to the naked eye have an apparent magnitude of about 6

Accepted Answer

A) True 
 B)False

Question 14

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 hydrogen-burning stars with the shortest lifetimes?

Accepted Answer

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

Question 15

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

Accepted Answer

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

Question 16

Which star cluster is the youngest star cluster? The one where the brightest main sequence stars are . . .

Accepted Answer

A)  O stars. 
B)  A stars. 
C)  G stars. 
D)  M stars. 
E)  B stars. 
A)  O stars. 
B)  A stars. 
C)  G stars. 
D)  M stars. 
E)  B stars.

Question 17

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 youngest?

Accepted Answer

A)   
B)   
C)   
D)   
A)   
B)   
C)   
D)

Question 18

Which of the following luminosity classes refers to stars on the main sequence?

Accepted Answer

A)  I 
B)  II 
C)  III 
D)  IV 
E)  V 
A)  I 
B)  II 
C)  III 
D)  IV 
E)  V

Question 19

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 10 billion years old?

Accepted Answer

A)   
B)   
C)   
D)   
A)   
B)   
C)   
D)

Question 20

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 with the longest main-sequence lifetimes?

Accepted Answer

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

The spectral sequence sorts stars according to

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

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 have no ongoing nuclear fusion?

The approximate main-sequence lifetime of a star of spectral type O is ________.

On an H-R diagram, stellar radii ________.

Which of the following comparisons between low-mass stars and high-mass stars is true?

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

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 five times the earth's distance from the Sun.

Two stars, Betty and Wilma, are both on the main sequence. Betty is more luminous than Wilma. Which one has a hotter surface temperature? Which one is more massive? Which one is bigger? If they both formed at the same time, which one will evolve off the main sequence first?

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

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 the most common type of stars?

The faintest visible stars to the naked eye have an apparent magnitude of about 6

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

Which star cluster is the youngest star cluster? The one where the brightest main sequence stars are . . .

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 youngest?

Which of the following luminosity classes refers to stars on the main sequence?

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 10 billion years old?

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 with the longest main-sequence lifetimes?

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

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Exam 11: Surveying the Stars

The spectral sequence sorts stars according to

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

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 have no ongoing nuclear fusion?

The approximate main-sequence lifetime of a star of spectral type O is ________.

On an H-R diagram, stellar radii ________.

Which of the following comparisons between low-mass stars and high-mass stars is true?

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

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 five times the earth's distance from the Sun.

Two stars, Betty and Wilma, are both on the main sequence. Betty is more luminous than Wilma. Which one has a hotter surface temperature? Which one is more massive? Which one is bigger? If they both formed at the same time, which one will evolve off the main sequence first?

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

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 the most common type of stars?

The faintest visible stars to the naked eye have an apparent magnitude of about 6

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

Which star cluster is the youngest star cluster? The one where the brightest main sequence stars are . . .

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 youngest?

Which of the following luminosity classes refers to stars on the main sequence?

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 10 billion years old?

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 with the longest main-sequence lifetimes?

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