Question 1

The apparent brightness of a star depends only on its luminosity.

Accepted Answer

A) True 
 B)False

Question 2

Which of the following stars has a spectrum that peaks at the highest frequency?

Accepted Answer

A)  A yellow star 
B)  A red star 
C)  A blue star 
A)  A yellow star 
B)  A red star 
C)  A blue star

Question 3

Observing Stellar Evolution: Stars evolve on timescales of millions to billions of years, making it impossible for astronomers to follow the life-cycle of any individual star. Explain how astronomers overcome this limitation. Be sure to discuss the important role that observations of star clusters play in revealing the evolution of stars.

Accepted Answer

Astronomers overcome the limitation of n

Question 4

A star's luminosity is the

Accepted Answer

A)  apparent brightness of the star in our sky. 
B)  surface temperature of the star. 
C)  lifetime of the star. 
D)  total amount of energy that the star will radiate over its entire lifetime. 
E)  total amount of energy that the star radiates each second. 
A)  apparent brightness of the star in our sky. 
B)  surface temperature of the star. 
C)  lifetime of the star. 
D)  total amount of energy that the star will radiate over its entire lifetime. 
E)  total amount of energy that the star radiates each second.

Question 5

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 oldest?

Accepted Answer

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

Question 6

On a Hertzsprung-Russell diagram, where on the main sequence would you find stars that have the greatest mass?

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 7

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

Accepted Answer

A) True 
 B)False

Question 8

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 fusing hydrogen in their cores?

Accepted Answer

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

Question 9

What is the approximate chemical composition (by mass) with which all stars are born?

Accepted Answer

A)  Three quarters hydrogen, one quarter helium, no more than 2% heavier elements 
B)  Half hydrogen and half helium 
C)  98% hydrogen, 2% helium 
D)  95% hydrogen, 4% helium, no more than 1% heavier elements 
A)  Three quarters hydrogen, one quarter helium, no more than 2% heavier elements 
B)  Half hydrogen and half helium 
C)  98% hydrogen, 2% helium 
D)  95% hydrogen, 4% helium, no more than 1% heavier elements

Question 10

What are the standard units for apparent brightness?

Accepted Answer

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

Question 11

Two stars, Tom and Jerry, have the same spectral type. Tom is luminosity class V and Jerry is luminosity class I. Which star is bigger? Which star is more luminous? Which star has a hotter surface temperature? Explain your answers.

Accepted Answer

Tom is on the main sequence, while Jerry

Question 12

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

Accepted Answer

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

Question 13

All stars spend approximately the same amount of time on the main sequence.

Accepted Answer

A) True 
 B)False

Question 14

What is a white dwarf?

Accepted Answer

A)  The remains of a star that ran out of fuel for nuclear fusion 
B)  A main sequence star of spectral type F, which tends to look white in color 
C)  It is a type of star that produces energy by gravitational contraction. 
D)  It is a star that follows a period-luminosity relation. 
A)  The remains of a star that ran out of fuel for nuclear fusion 
B)  A main sequence star of spectral type F, which tends to look white in color 
C)  It is a type of star that produces energy by gravitational contraction. 
D)  It is a star that follows a period-luminosity relation.

Question 15

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

Accepted Answer

A) True 
 B)False

Question 16

It is impossible for a star to have a negative apparent magnitude, such as -1.

Accepted Answer

A) True 
 B)False

Question 17

On an H-R diagram, stellar masses ________.

Accepted Answer

A)  can be determined for main sequence stars but not for other types of stars 
B)  are greatest in the lower left and least in the upper right 
C)  decrease from upper left to lower right 
D)  are impossible to determine 
A)  can be determined for main sequence stars but not for other types of stars 
B)  are greatest in the lower left and least in the upper right 
C)  decrease from upper left to lower right 
D)  are impossible to determine

Question 18

What do we mean by the main-sequence turnoff point of a star cluster, and what does it tell us?

Accepted Answer

A)  It is the spectral type of the hottest main sequence star in a star cluster, and it tells us the cluster's age. 
B)  It is the point in a star cluster beyond which main sequence stars are not found, and it tells us the cluster's distance. 
C)  It is the luminosity class of the largest star in a star cluster, and it tells us the cluster's age. 
D)  It is the mass of the most massive star in the star cluster, and it tells us the cluster's size. 
A)  It is the spectral type of the hottest main sequence star in a star cluster, and it tells us the cluster's age. 
B)  It is the point in a star cluster beyond which main sequence stars are not found, and it tells us the cluster's distance. 
C)  It is the luminosity class of the largest star in a star cluster, and it tells us the cluster's age. 
D)  It is the mass of the most massive star in the star cluster, and it tells us the cluster's size.

Question 19

Which of the following terms is given to a pair of stars that appear to change position in the sky, indicating that they are orbiting one another?

Accepted Answer

A)  visual binary 
B)  eclipsing binary 
C)  spectroscopic binary 
D)  double star 
E)  none of the above 
A)  visual binary 
B)  eclipsing binary 
C)  spectroscopic binary 
D)  double star 
E)  none of the above

Question 20

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 
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

The apparent brightness of a star depends only on its luminosity.

Which of the following stars has a spectrum that peaks at the highest frequency?

A star's luminosity is the

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 oldest?

On a Hertzsprung-Russell diagram, where on the main sequence would you find stars that have the greatest mass?

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

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 fusing hydrogen in their cores?

What is the approximate chemical composition (by mass) with which all stars are born?

What are the standard units for apparent brightness?

Two stars, Tom and Jerry, have the same spectral type. Tom is luminosity class V and Jerry is luminosity class I. Which star is bigger? Which star is more luminous? Which star has a hotter surface temperature? Explain your answers.

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

All stars spend approximately the same amount of time on the main sequence.

What is a white dwarf?

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

It is impossible for a star to have a negative apparent magnitude, such as -1.

On an H-R diagram, stellar masses ________.

What do we mean by the main-sequence turnoff point of a star cluster, and what does it tell us?

Which of the following terms is given to a pair of stars that appear to change position in the sky, indicating that they are orbiting one another?

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

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

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Exam 11: Surveying the Stars

The apparent brightness of a star depends only on its luminosity.

Which of the following stars has a spectrum that peaks at the highest frequency?

A star's luminosity is the

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 oldest?

On a Hertzsprung-Russell diagram, where on the main sequence would you find stars that have the greatest mass?

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

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 fusing hydrogen in their cores?

What is the approximate chemical composition (by mass) with which all stars are born?

What are the standard units for apparent brightness?

Two stars, Tom and Jerry, have the same spectral type. Tom is luminosity class V and Jerry is luminosity class I. Which star is bigger? Which star is more luminous? Which star has a hotter surface temperature? Explain your answers.

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

All stars spend approximately the same amount of time on the main sequence.

What is a white dwarf?

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

It is impossible for a star to have a negative apparent magnitude, such as -1.

On an H-R diagram, stellar masses ________.

What do we mean by the main-sequence turnoff point of a star cluster, and what does it tell us?

Which of the following terms is given to a pair of stars that appear to change position in the sky, indicating that they are orbiting one another?

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

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