Question 1

The formation of one of the following phenomena requires that a young hot star (T = 25,000 K) be relatively close by. Which one?

Accepted Answer

A)  emission nebulae 
B)  HI regions 
C)  molecular clouds 
D)  21-centimetre radiation 
A)  emission nebulae 
B)  HI regions 
C)  molecular clouds 
D)  21-centimetre radiation

Question 2

What evidence can be used to show that space is not a vacuum?

Accepted Answer

A)  ultraviolet radiation emitted by dust 
B)  narrow emission lines seen in stellar spectra 
C)  the presence of bright nebulae 
D)  the blue colour of stars seen near dark regions 
A)  ultraviolet radiation emitted by dust 
B)  narrow emission lines seen in stellar spectra 
C)  the presence of bright nebulae 
D)  the blue colour of stars seen near dark regions

Question 3

Why is convection important in stars?

Accepted Answer

A)  because it mixes the star's gases and increases the temperature of the star 
B)  because it mixes the star's gases and transports energy outwards 
C)  because it carries energy toward the core of the star 
D)  because it carries the neutrinos to the surface of the star where they can escape 
A)  because it mixes the star's gases and increases the temperature of the star 
B)  because it mixes the star's gases and transports energy outwards 
C)  because it carries energy toward the core of the star 
D)  because it carries the neutrinos to the surface of the star where they can escape

Question 4

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 5

Which of the following are star-like objects that contain less than 0.08 solar masses and will never raise their core temperatures high enough that the proton-proton chain can begin?

Accepted Answer

A)  brown dwarfs 
B)  Herbig-Haro objects 
C)  Bok globules 
D)  T Tauri stars 
A)  brown dwarfs 
B)  Herbig-Haro objects 
C)  Bok globules 
D)  T Tauri stars

Question 6

How did observations at the Sudbury Neutrino Observatory solve the solar neutrino problem?

Accepted Answer

A)  They showed that the "missing neutrinos" had changed into a different type. 
B)  They showed that other experiments had miscounted the number of solar neutrinos. 
C)  They showed that models for the number of neutrinos produced by the Sun were wrong. 
D)  They showed that neutrinos were not escaping from the core of the Sun. 
A)  They showed that the "missing neutrinos" had changed into a different type. 
B)  They showed that other experiments had miscounted the number of solar neutrinos. 
C)  They showed that models for the number of neutrinos produced by the Sun were wrong. 
D)  They showed that neutrinos were not escaping from the core of the Sun.

Question 7

Bok globules are small, dark fragments of the interstellar medium.

Accepted Answer

A) True 
 B)False

Question 8

Which of the following is considered to be the best explanation for the missing solar neutrinos?

Accepted Answer

A)  The Sun is fusing helium but not hydrogen. 
B)  Nuclear reactions do not produce neutrinos as fast as theory predicts. 
C)  The Sun may contain matter we haven't yet identified. 
D)  Neutrinos may oscillate between three different flavours. 
A)  The Sun is fusing helium but not hydrogen. 
B)  Nuclear reactions do not produce neutrinos as fast as theory predicts. 
C)  The Sun may contain matter we haven't yet identified. 
D)  Neutrinos may oscillate between three different flavours.

Question 9

The nucleus of the hydrogen atom consists of a single neutron.

Accepted Answer

A) True 
 B)False

Question 10

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 that 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 11

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 12

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 13

A group of stars that formed together but are not held together by gravity is called a(n) ___________________.

Accepted Answer

The answer of A group of stars that formed together...

Question 14

The solar neutrino experiments detected about twice as many neutrinos as theory predicted should be detected.

Accepted Answer

A) True 
 B)False

Question 15

Which of the following is most similar in size to a brown dwarf?

Accepted Answer

A)  the planet Jupiter 
B)  a red dwarf 
C)  a white dwarf 
D)  a Bok globule 
A)  the planet Jupiter 
B)  a red dwarf 
C)  a white dwarf 
D)  a Bok globule

Question 16

Relative to a sunlike star, how should the region where convection dominates be different within a cooler star?

Accepted Answer

A)  Convection should dominate within a smaller fraction of the star's surface. 
B)  Convection should dominate within a larger fraction of the star's surface. 
C)  Convection should dominate within a smaller fraction of the star's core. 
D)  Convection should dominate within a larger fraction of the star's core. 
A)  Convection should dominate within a smaller fraction of the star's surface. 
B)  Convection should dominate within a larger fraction of the star's surface. 
C)  Convection should dominate within a smaller fraction of the star's core. 
D)  Convection should dominate within a larger fraction of the star's core.

Question 17

The Sun has a core in which energy travels outward primarily by radiation.

Accepted Answer

A) True 
 B)False

Question 18

Why does the proton-proton chain need high temperatures?

Accepted Answer

A)  High temperatures increase the ground state energy of the hydrogen atom. 
B)  High temperatures increase the velocity of the protons so they can overcome the Coulomb barrier. 
C)  High temperatures lower the density of the gas. 
D)  High temperatures allow the neutrinos to carry more energy away than the reaction produces. 
A)  High temperatures increase the ground state energy of the hydrogen atom. 
B)  High temperatures increase the velocity of the protons so they can overcome the Coulomb barrier. 
C)  High temperatures lower the density of the gas. 
D)  High temperatures allow the neutrinos to carry more energy away than the reaction produces.

Question 19

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 20

A star on the _________ ________________ generates enough energy from nuclear fusion to halt gravitational collapse.

Accepted Answer

The answer of A star on the _________ ________________ generates...

The formation of one of the following phenomena requires that a young hot star (T = 25,000 K) be relatively close by. Which one?

What evidence can be used to show that space is not a vacuum?

Why is convection important in stars?

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?

Which of the following are star-like objects that contain less than 0.08 solar masses and will never raise their core temperatures high enough that the proton-proton chain can begin?

How did observations at the Sudbury Neutrino Observatory solve the solar neutrino problem?

Bok globules are small, dark fragments of the interstellar medium.

Which of the following is considered to be the best explanation for the missing solar neutrinos?

The nucleus of the hydrogen atom consists of a single neutron.

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 that their mutual gravity cannot hold them together?

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

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

A group of stars that formed together but are not held together by gravity is called a(n) ___________________.

The solar neutrino experiments detected about twice as many neutrinos as theory predicted should be detected.

Which of the following is most similar in size to a brown dwarf?

Relative to a sunlike star, how should the region where convection dominates be different within a cooler star?

The Sun has a core in which energy travels outward primarily by radiation.

Why does the proton-proton chain need high temperatures?

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

A star on the _ ________ generates enough energy from nuclear fusion to halt gravitational collapse.

The Scale of the Cosmos: Space and Time

Users Guide to the Sky: Patterns and Cycles

The Origin of Modern Astronomy

Astronomical Telescopes and Instruments: Extending Humanitys Vision

The Sun: the Closest Star

The Family of Stars

The Deaths of Stars

The Milky Way Galaxy

Galaxies

Cosmology in the 21st Century

Planet Formation and Exoplanets

Comparative Planetology of the Terrestrial Planets

The Outer Solar System

Life on Other Worlds

Filters

Exam 7: The Structure and Formation of Stars

The formation of one of the following phenomena requires that a young hot star (T = 25,000 K) be relatively close by. Which one?

What evidence can be used to show that space is not a vacuum?

Why is convection important in stars?

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?

Which of the following are star-like objects that contain less than 0.08 solar masses and will never raise their core temperatures high enough that the proton-proton chain can begin?

How did observations at the Sudbury Neutrino Observatory solve the solar neutrino problem?

Bok globules are small, dark fragments of the interstellar medium.

Which of the following is considered to be the best explanation for the missing solar neutrinos?

The nucleus of the hydrogen atom consists of a single neutron.

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 that their mutual gravity cannot hold them together?

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

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

A group of stars that formed together but are not held together by gravity is called a(n) ___________________.

The solar neutrino experiments detected about twice as many neutrinos as theory predicted should be detected.

Which of the following is most similar in size to a brown dwarf?

Relative to a sunlike star, how should the region where convection dominates be different within a cooler star?

The Sun has a core in which energy travels outward primarily by radiation.

Why does the proton-proton chain need high temperatures?

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

A star on the _________ ________________ generates enough energy from nuclear fusion to halt gravitational collapse.

The Scale of the Cosmos: Space and Time

Users Guide to the Sky: Patterns and Cycles

The Origin of Modern Astronomy

Astronomical Telescopes and Instruments: Extending Humanitys Vision

The Sun: the Closest Star

The Family of Stars

The Deaths of Stars

The Milky Way Galaxy

Galaxies

Cosmology in the 21st Century

Planet Formation and Exoplanets

Comparative Planetology of the Terrestrial Planets

The Outer Solar System

Life on Other Worlds

Filters

A star on the _ ________ generates enough energy from nuclear fusion to halt gravitational collapse.