Question 1

-Refer to the H-R diagram.Which of the points represents a star in which the CNO cycle is occurring?

Accepted Answer

A) 1 
B) 2 
C) 3 
D) 4 
A) 1 
B) 2 
C) 3 
D) 4

Question 2

Because they are composed of ionized hydrogen,emission nebulae have another name - what is that name?

Accepted Answer

A) HI regions 
B) HII regions 
C) Bok globules 
D) HeI regions 
A) HI regions 
B) HII regions 
C) Bok globules 
D) HeI regions

Question 3

What is the term for a group of 10 to 100 stars that formed at the same time but are so widely scattered in space their mutual gravity cannot hold them together?

Accepted Answer

A) a globular cluster 
B) an open cluster 
C) an association 
D) a spherical component 
A) a globular cluster 
B) an open cluster 
C) an association 
D) a spherical component

Question 4

While on the main sequence,what is a star's primary energy source?

Accepted Answer

A) nuclear fusion 
B) nuclear fission 
C) gravitational potential energy 
D) magnetic fields 
A) nuclear fusion 
B) nuclear fission 
C) gravitational potential energy 
D) magnetic fields

Question 5

Why are distant stars redder than nearby stars of the same spectral type?

Accepted Answer

The answer of Why are distant stars redder than nearby...

Question 6

A(n)____________________ is a cool,dense cloud of dust and gas that is undergoing gravitational contraction.

Accepted Answer

The answer of A(n)____________________ is a cool,dense cloud of dust...

Question 7

What is the approximate mass of the lowest mass object that can initiate the thermonuclear fusion of hydrogen?

Accepted Answer

A) 0.08 solar mass 
B) 1 solar mass 
C) 8 solar masses 
D) 80 solar masses 
A) 0.08 solar mass 
B) 1 solar mass 
C) 8 solar masses 
D) 80 solar masses

Question 8

Which of the following is the best example of energy transport by conduction?

Accepted Answer

A) Your feet are warmed when you hold them in front of a fire. 
B) Your feet are warmed when you wear socks. 
C) Your feet get cold when you stand on a cold floor. 
D) Your feet get cold when you hold them over a cool air vent. 
A) Your feet are warmed when you hold them in front of a fire. 
B) Your feet are warmed when you wear socks. 
C) Your feet get cold when you stand on a cold floor. 
D) Your feet get cold when you hold them over a cool air vent.

Question 9

How much of its lifetime does the average star spend on the main sequence?

Accepted Answer

A) 1% 
B) 10% 
C) 20% 
D) 90% 
A) 1% 
B) 10% 
C) 20% 
D) 90%

Question 10

What observations demonstrate the existence of an interstellar medium?

Accepted Answer

The answer of What observations demonstrate the existence of an...

Question 11

What occurs when some of the material collapsing to form a protostar is ejected from its poles?

Accepted Answer

A) A protoplanetary disk forms. 
B) The star stops collapsing. 
C) The T Tauri phenomenon occurs. 
D) Jets extend into the interstellar medium. 
A) A protoplanetary disk forms. 
B) The star stops collapsing. 
C) The T Tauri phenomenon occurs. 
D) Jets extend into the interstellar medium.

Question 12

Star clusters are important to the study of stellar evolution because all the stars in a given cluster have one thing in common.What is it?

Accepted Answer

A) temperature 
B) mass 
C) age 
D) luminosity 
A) temperature 
B) mass 
C) age 
D) luminosity

Question 13

What is opacity?

Accepted Answer

A) the balance between the pressure and force of gravity inside a star 
B) the force that binds protons and neutrons together to form a nucleus 
C) the temperature and density at which a gas will undergo thermonuclear fusion 
D) a measure of the resistance to the flow of radiation (photons) through a gas 
A) the balance between the pressure and force of gravity inside a star 
B) the force that binds protons and neutrons together to form a nucleus 
C) the temperature and density at which a gas will undergo thermonuclear fusion 
D) a measure of the resistance to the flow of radiation (photons) through a gas

Question 14

The lower edge of the main-sequence band represents the location in the H-R diagram at which stars begin their lives as main-sequence stars.What is it called?

Accepted Answer

A) the zero-age main sequence 
B) the birth line 
C) the Coulomb barrier 
D) the evolutionary track 
A) the zero-age main sequence 
B) the birth line 
C) the Coulomb barrier 
D) the evolutionary track

Question 15

Why are emission nebulae associated with young stars?

Accepted Answer

A) Young stars have not moved far from the gaseous nebulae where they were born. 
B) Only hot stars can ionize nearby gas; hot stars are high-mass, so must be young. 
C) The dust that makes emission nebulae glow is destroyed by old stars. 
D) Young stars produce the blue light that is scattered by emission nebulae. 
A) Young stars have not moved far from the gaseous nebulae where they were born. 
B) Only hot stars can ionize nearby gas; hot stars are high-mass, so must be young. 
C) The dust that makes emission nebulae glow is destroyed by old stars. 
D) Young stars produce the blue light that is scattered by emission nebulae.

Question 16

What would a H-R diagram of a young star cluster show?

Accepted Answer

A) high mass stars that have not reached the main sequence yet 
B) low mass stars that have not reached the main sequence yet 
C) mainly giant stars, since most stars have left the main sequence 
D) no stars, since none have reached the main sequence yet 
A) high mass stars that have not reached the main sequence yet 
B) low mass stars that have not reached the main sequence yet 
C) mainly giant stars, since most stars have left the main sequence 
D) no stars, since none have reached the main sequence yet

Question 17

What causes the outward gas pressure that balances the inward pull of gravity in a main-sequence star?

Accepted Answer

A) the rapid outward flow of gas 
B) the rapid inward flow of gas 
C) the high temperature and density of the gas 
D) the low mass of helium nuclei 
A) the rapid outward flow of gas 
B) the rapid inward flow of gas 
C) the high temperature and density of the gas 
D) the low mass of helium nuclei

Question 18

Stars with masses greater than 1.1 solar masses use the ____________________ to convert hydrogen into helium and produce energy

Accepted Answer

The answer of Stars with masses greater than 1.1 solar...

Question 19

The condition of ____________________ means that the force due to gravity pushing downward on a layer is exactly equal to the pressure pushing upward on that layer.

Accepted Answer

hydrostati

Question 20

What is the term for the process that fuses hydrogen into helium in the cores of massive main-sequence stars?

Accepted Answer

A) the CNO cycle 
B) the proton-proton chain 
C) hydrostatic equilibrium 
D) the neutrino process 
A) the CNO cycle 
B) the proton-proton chain 
C) hydrostatic equilibrium 
D) the neutrino process

-Refer to the H-R diagram.Which of the points represents a star in which the CNO cycle is occurring?

Because they are composed of ionized hydrogen,emission nebulae have another name - what is that name?

What is the term for a group of 10 to 100 stars that formed at the same time but are so widely scattered in space their mutual gravity cannot hold them together?

While on the main sequence,what is a star's primary energy source?

Why are distant stars redder than nearby stars of the same spectral type?

A(n)____________________ is a cool,dense cloud of dust and gas that is undergoing gravitational contraction.

What is the approximate mass of the lowest mass object that can initiate the thermonuclear fusion of hydrogen?

Which of the following is the best example of energy transport by conduction?

How much of its lifetime does the average star spend on the main sequence?

What observations demonstrate the existence of an interstellar medium?

What occurs when some of the material collapsing to form a protostar is ejected from its poles?

Star clusters are important to the study of stellar evolution because all the stars in a given cluster have one thing in common.What is it?

What is opacity?

The lower edge of the main-sequence band represents the location in the H-R diagram at which stars begin their lives as main-sequence stars.What is it called?

Why are emission nebulae associated with young stars?

What would a H-R diagram of a young star cluster show?

What causes the outward gas pressure that balances the inward pull of gravity in a main-sequence star?

Stars with masses greater than 1.1 solar masses use the ____________________ to convert hydrogen into helium and produce energy

The condition of ____________________ means that the force due to gravity pushing downward on a layer is exactly equal to the pressure pushing upward on that layer.

What is the term for the process that fuses hydrogen into helium in the cores of massive main-sequence stars?

The Scale of the Cosmos

User's Guide to the Sky

The Origin of Modern Astronomy

Astronomical Telescopes and Instruments

Sun Light and Sun Atoms

The Family of Stars

The Deaths of Stars

The Milky Way Galaxy

Galaxies

Cosmology in the 21st Century

The Origin of the Solar System

Comparative Planetology of the Terrestrial Planets

Comparative Planetology of the Jovian Planets

Life on Other Worlds

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Exam 7: The Structure and Formation of Stars

-Refer to the H-R diagram.Which of the points represents a star in which the CNO cycle is occurring?

Because they are composed of ionized hydrogen,emission nebulae have another name - what is that name?

What is the term for a group of 10 to 100 stars that formed at the same time but are so widely scattered in space their mutual gravity cannot hold them together?

While on the main sequence,what is a star's primary energy source?

Why are distant stars redder than nearby stars of the same spectral type?

A(n)____________________ is a cool,dense cloud of dust and gas that is undergoing gravitational contraction.

What is the approximate mass of the lowest mass object that can initiate the thermonuclear fusion of hydrogen?

Which of the following is the best example of energy transport by conduction?

How much of its lifetime does the average star spend on the main sequence?

What observations demonstrate the existence of an interstellar medium?

What occurs when some of the material collapsing to form a protostar is ejected from its poles?

Star clusters are important to the study of stellar evolution because all the stars in a given cluster have one thing in common.What is it?

What is opacity?

The lower edge of the main-sequence band represents the location in the H-R diagram at which stars begin their lives as main-sequence stars.What is it called?

Why are emission nebulae associated with young stars?

What would a H-R diagram of a young star cluster show?

What causes the outward gas pressure that balances the inward pull of gravity in a main-sequence star?

Stars with masses greater than 1.1 solar masses use the ____________________ to convert hydrogen into helium and produce energy

The condition of ____________________ means that the force due to gravity pushing downward on a layer is exactly equal to the pressure pushing upward on that layer.

What is the term for the process that fuses hydrogen into helium in the cores of massive main-sequence stars?

The Scale of the Cosmos

User's Guide to the Sky

The Origin of Modern Astronomy

Astronomical Telescopes and Instruments

Sun Light and Sun Atoms

The Family of Stars

The Deaths of Stars

The Milky Way Galaxy

Galaxies

Cosmology in the 21st Century

The Origin of the Solar System

Comparative Planetology of the Terrestrial Planets

Comparative Planetology of the Jovian Planets

Life on Other Worlds

Filters