Question 1

How can the coronal gas occupy most of the space but represent only 5% of the mass?

Accepted Answer

A)  It has a much lower pressure than the other components. 
B)  It has a much higher pressure than the other components. 
C)  It has a much lower temperature than the other components. 
D)  It has a much higher density than the other components. 
E)  It has a much lower density than the other components. 
A)  It has a much lower pressure than the other components. 
B)  It has a much higher pressure than the other components. 
C)  It has a much lower temperature than the other components. 
D)  It has a much higher density than the other components. 
E)  It has a much lower density than the other components.

Question 2

To an observer on Earth,dust in the interstellar medium will cause a star to appear

Accepted Answer

A)  brighter and cooler than it really is. 
B)  brighter and hotter than it really is. 
C)  fainter and cooler than it really is. 
D)  fainter and hotter than it really is. 
E)  unchanged in brightness or apparent color. 
A)  brighter and cooler than it really is. 
B)  brighter and hotter than it really is. 
C)  fainter and cooler than it really is. 
D)  fainter and hotter than it really is. 
E)  unchanged in brightness or apparent color.

Question 3

____________________ is the most abundant element in the interstellar medium.

Accepted Answer

The answer of ____________________ is the most abundant element in...

Question 4

Atoms of cool hydrogen emit 21-cm radiation when the

Accepted Answer

A)  electrons move from the fourth to the second energy level. 
B)  electrons move from the second to the fourth energy level. 
C)  protons change their spin. 
D)  electrons change their spin. 
E)  hydrogen atoms add a second electron to form H-. 
A)  electrons move from the fourth to the second energy level. 
B)  electrons move from the second to the fourth energy level. 
C)  protons change their spin. 
D)  electrons change their spin. 
E)  hydrogen atoms add a second electron to form H-.

Question 5

X-rays come from certain regions of the interstellar medium because

Accepted Answer

A)  those regions are heated to a very high temperature. 
B)  gas molecules in those regions are at a very high density. 
C)  dust and gas in those regions are moving very rapidly. 
D)  nuclear fusion is occurring in those regions. 
A)  those regions are heated to a very high temperature. 
B)  gas molecules in those regions are at a very high density. 
C)  dust and gas in those regions are moving very rapidly. 
D)  nuclear fusion is occurring in those regions.

Question 6

The pressure of a gas depends on the temperature and density of the gas.

Accepted Answer

A) True 
 B)False

Question 7

What property of blue light allows it to be more readily scattered than red light?

Accepted Answer

A)  Higher intensity 
B)  Faster speed 
C)  Higher temperature 
D)  Shorter wavelength 
A)  Higher intensity 
B)  Faster speed 
C)  Higher temperature 
D)  Shorter wavelength

Question 8

Interstellar dust scatters _______ light more than ____________ light..

Accepted Answer

A)  blue 
B)  red 
C)  Both are scattered equal amounts 
D)  Neither are scattered by interstellar dust 
A)  blue 
B)  red 
C)  Both are scattered equal amounts 
D)  Neither are scattered by interstellar dust

Question 9

The term "metastable levels" refers to

Accepted Answer

A)  regions within a molecular cloud that are not moving relative to the rest of the cloud. 
B)  the upper energy level of the 21-cm transition in the hydrogen atom. 
C)  the lower energy level of the 21-cm transition in the hydrogen atom. 
D)  the boundary layers between HI regions and the hotter intercloud medium. 
E)  energy levels in an atom that require a much longer time than average to decay and emit a photon. 
A)  regions within a molecular cloud that are not moving relative to the rest of the cloud. 
B)  the upper energy level of the 21-cm transition in the hydrogen atom. 
C)  the lower energy level of the 21-cm transition in the hydrogen atom. 
D)  the boundary layers between HI regions and the hotter intercloud medium. 
E)  energy levels in an atom that require a much longer time than average to decay and emit a photon.

Question 10

Molecular clouds are mapped using CO instead of hydrogen because CO is much more abundant than hydrogen in molecular clouds.

Accepted Answer

A) True 
 B)False

Question 11

The emission lines from O III are called forbidden because they cannot occur in laboratories on Earth due to the much greater pressure of the gas on Earth.

Accepted Answer

A) True 
 B)False

How can the coronal gas occupy most of the space but represent only 5% of the mass?

To an observer on Earth,dust in the interstellar medium will cause a star to appear

____________________ is the most abundant element in the interstellar medium.

Atoms of cool hydrogen emit 21-cm radiation when the

X-rays come from certain regions of the interstellar medium because

The pressure of a gas depends on the temperature and density of the gas.

What property of blue light allows it to be more readily scattered than red light?

Interstellar dust scatters _ light more than ______ light..

The term "metastable levels" refers to

Molecular clouds are mapped using CO instead of hydrogen because CO is much more abundant than hydrogen in molecular clouds.

The emission lines from O III are called forbidden because they cannot occur in laboratories on Earth due to the much greater pressure of the gas on Earth.

Here and Now

A Users Guide to the Sky

Cycles of the Moon

The Origin of Modern Astronomy

Gravity

Light and Telescopes

Atoms and Spectra

The Sun

The Family of Stars

The Formation and Structure of Stars

Stellar Evolution

The Deaths of Stars

Neutron Stars and Black Holes

The Milky Way Galaxy

Galaxies

Active Galaxies and Supermassive Black Holes

Modern Cosmology

The Origin of the Solar System

Earth: the Standard of Comparative Planetology

The Moon and Mercury: Comparing Airless Worlds

Venus and Mars

Jupiter and Saturn

Uranus,neptune,and the Kuiper Belt

Meteorites,asteroids,and Comets

Astrobiology: Life on Other Worlds

Filters

Exam 10: The Interstellar Medium

How can the coronal gas occupy most of the space but represent only 5% of the mass?

To an observer on Earth,dust in the interstellar medium will cause a star to appear

____________________ is the most abundant element in the interstellar medium.

Atoms of cool hydrogen emit 21-cm radiation when the

X-rays come from certain regions of the interstellar medium because

The pressure of a gas depends on the temperature and density of the gas.

What property of blue light allows it to be more readily scattered than red light?

Interstellar dust scatters _______ light more than ____________ light..

The term "metastable levels" refers to

Molecular clouds are mapped using CO instead of hydrogen because CO is much more abundant than hydrogen in molecular clouds.

The emission lines from O III are called forbidden because they cannot occur in laboratories on Earth due to the much greater pressure of the gas on Earth.

Here and Now

A Users Guide to the Sky

Cycles of the Moon

The Origin of Modern Astronomy

Gravity

Light and Telescopes

Atoms and Spectra

The Sun

The Family of Stars

The Formation and Structure of Stars

Stellar Evolution

The Deaths of Stars

Neutron Stars and Black Holes

The Milky Way Galaxy

Galaxies

Active Galaxies and Supermassive Black Holes

Modern Cosmology

The Origin of the Solar System

Earth: the Standard of Comparative Planetology

The Moon and Mercury: Comparing Airless Worlds

Venus and Mars

Jupiter and Saturn

Uranus,neptune,and the Kuiper Belt

Meteorites,asteroids,and Comets

Astrobiology: Life on Other Worlds

Filters

Interstellar dust scatters _ light more than ______ light..