Question 1

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

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 A

Question 2

The axes on a Hertzsprung- Russell (H- R)diagram represent _ .

Accepted Answer

A) mass and luminosity 
B) mass and radius 
C) luminosity and surface temperature 
D) luminosity and apparent brightness 
A) mass and luminosity 
B) mass and radius 
C) luminosity and surface temperature 
D) luminosity and apparent brightness C

Question 3

A star of spectral type G lives approximately how long on the main sequence?

Accepted Answer

A) 10,000 years 
B) 1 billion years 
C) 1,000 years 
D) 10 billion years 
E) 10 million years 
A) 10,000 years 
B) 1 billion years 
C) 1,000 years 
D) 10 billion years 
E) 10 million years D

Question 4

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

Accepted Answer

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

Question 5

A star is observed with a surface temperature of 3,000 K and a luminosity of 10-2 solar. What is the approximate mass of this star?

Accepted Answer

A) 0)5 Msun 
B) 0)2 Msun 
C) 0)9 Msun 
D) The mass cannot be determined. 
A) 0)5 Msun 
B) 0)2 Msun 
C) 0)9 Msun 
D) The mass cannot be determined.

Question 6

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

Accepted Answer

A) A star with an apparent magnitude of 1 appears brighter than a star with an apparent magnitude of 2. 
B) The absolute magnitude of a star is another measure of its luminosity. 
C) A star's absolute magnitude is the apparent magnitude it would have if it were at a distance of 10 parsecs from Earth. 
D) 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. 
E) All of the above are true. 
A) A star with an apparent magnitude of 1 appears brighter than a star with an apparent magnitude of 2. 
B) The absolute magnitude of a star is another measure of its luminosity. 
C) A star's absolute magnitude is the apparent magnitude it would have if it were at a distance of 10 parsecs from Earth. 
D) 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. 
E) All of the above are true.

Question 7

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 8

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 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 half the earth's distance from the Sun.

Accepted Answer

The Sun would appear four time

Question 10

The most distant stars we can currently measure stellar parallax for are approximately

Accepted Answer

A) 1,000 parsecs away. 
B) 10,000 parsecs away. 
C) in the Andromeda Galaxy. 
D) halfway across the Milky Way Galaxy. 
E) 5 parsecs away. 
A) 1,000 parsecs away. 
B) 10,000 parsecs away. 
C) in the Andromeda Galaxy. 
D) halfway across the Milky Way Galaxy. 
E) 5 parsecs away.

Question 11

On a Hertzsprung- Russell diagram, where would you find white dwarfs?

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 12

Inferring stellar lifetimes: Scientists must often draw on a variety of concepts to develop new understanding. Take, for example, the inferred lifetimes of stars. What two properties must be precisely measured in order to estimate the lifetime? Outline the set of observations that must be made in order to determine those properties. Then discuss the fundamental physics that must be understood to relate these to the rate at which hydrogen is converted to helium in the stellar core, and to determine the amount of hydrogen available in the core.

Accepted Answer

Should include description of the measur

Question 13

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? What are their relative locations on the HR diagram?

Accepted Answer

Barney has a hotter surface te

Question 14

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

Accepted Answer

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

Question 15

You see two main- sequence stars with the same spectral type. Star 1 is dimmer in apparent brightness than Star 2 by a factor of 100. What can you conclude, assuming there is no absorption of either star's light by interstellar gas or dust?

Accepted Answer

A) Without first knowing the distances to these stars, you cannot draw any conclusions about how their true luminosities compare to each other. 
B) Star 1 is 10 times more distant than Star 2. 
C) Star 1 is 100 times nearer than Star 2. 
D) Star 1 is 100 times more distant than Star 2. 
E) The luminosity of Star 1 is a factor of 100 less than the luminosity of Star 2. 
A) Without first knowing the distances to these stars, you cannot draw any conclusions about how their true luminosities compare to each other. 
B) Star 1 is 10 times more distant than Star 2. 
C) Star 1 is 100 times nearer than Star 2. 
D) Star 1 is 100 times more distant than Star 2. 
E) The luminosity of Star 1 is a factor of 100 less than the luminosity of Star 2.

Question 16

Spectral type, surface temperature, and color all describe the same basic characteristic of a star.

Accepted Answer

A) True 
 B)False

Question 17

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

Accepted Answer

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

Question 18

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 19

Explain why stars more massive than the Sun live shorter main sequence lives than stars less massive than the Sun, despite having more fuel available for nuclear reactions.

Accepted Answer

or 1/8 tha

Question 20

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

Accepted Answer

A) True 
 B)False

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

The axes on a Hertzsprung- Russell (H- R)diagram represent _ .

A star of spectral type G lives approximately how long on the main sequence?

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

A star is observed with a surface temperature of 3,000 K and a luminosity of 10-2 solar. What is the approximate mass of this star?

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

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

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

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.

The most distant stars we can currently measure stellar parallax for are approximately

On a Hertzsprung- Russell diagram, where would you find white dwarfs?

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? What are their relative locations on the HR diagram?

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

You see two main- sequence stars with the same spectral type. Star 1 is dimmer in apparent brightness than Star 2 by a factor of 100. What can you conclude, assuming there is no absorption of either star's light by interstellar gas or dust?

Spectral type, surface temperature, and color all describe the same basic characteristic of a star.

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

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?

Explain why stars more massive than the Sun live shorter main sequence lives than stars less massive than the Sun, despite having more fuel available for nuclear reactions.

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

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Exam 12: Surveying the Stars

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

The axes on a Hertzsprung- Russell (H- R)diagram represent _ .

A star of spectral type G lives approximately how long on the main sequence?

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

A star is observed with a surface temperature of 3,000 K and a luminosity of 10-2 solar. What is the approximate mass of this star?

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

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

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

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.

The most distant stars we can currently measure stellar parallax for are approximately

On a Hertzsprung- Russell diagram, where would you find white dwarfs?

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? What are their relative locations on the HR diagram?

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

You see two main- sequence stars with the same spectral type. Star 1 is dimmer in apparent brightness than Star 2 by a factor of 100. What can you conclude, assuming there is no absorption of either star's light by interstellar gas or dust?

Spectral type, surface temperature, and color all describe the same basic characteristic of a star.

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

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?

Explain why stars more massive than the Sun live shorter main sequence lives than stars less massive than the Sun, despite having more fuel available for nuclear reactions.

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

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