Question 1

-Refer to the H-R diagram. Which point represents a star in which the proton-proton chain is occurring?

Accepted Answer

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

Question 2

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 3

HII regions are found near stars cooler than 25,000 K because large amounts of ultraviolet photons would totally destroy the hydrogen atoms in the gas.

Accepted Answer

A) True 
 B)False

Question 4

Upon observing a nebula, you discover that many stars are surrounded by disks of gas and dust. What can you conclude about these stars?

Accepted Answer

A)  They are very young. 
B)  They are very old. 
C)  They are red giants. 
D)  They are white dwarfs. 
A)  They are very young. 
B)  They are very old. 
C)  They are red giants. 
D)  They are white dwarfs.

Question 5

Which of the following factors explain why infrared telescopes are used to observe protostars?

Accepted Answer

A)  density and composition 
B)  density and the presence of dust 
C)  temperature and the presence of dust 
D)  temperature and luminosity 
A)  density and composition 
B)  density and the presence of dust 
C)  temperature and the presence of dust 
D)  temperature and luminosity

Question 6

____________________ is the resistance of a gas to the flow of radiation.

Accepted Answer

The answer of ____________________ is the resistance of a gas...

Question 7

Under what conditions might interstellar gas clouds collapse to form stars?

Accepted Answer

A)  if they encounter a shock wave 
B)  if they have very high temperatures 
C)  if they rotate rapidly 
D)  if they are located near main-sequence spectral type K and M stars 
A)  if they encounter a shock wave 
B)  if they have very high temperatures 
C)  if they rotate rapidly 
D)  if they are located near main-sequence spectral type K and M stars

Question 8

-The Sun has an expected main-sequence lifetime of about 10 billion years. About how long would a 2-solar-mass star stay on the main sequence?

Accepted Answer

A)  10 million years 
B)  1 billion years 
C)  10 billion years 
D)  20 billion years 
A)  10 million years 
B)  1 billion years 
C)  10 billion years 
D)  20 billion years

Question 9

What happens in the carbon-nitrogen-oxygen (CNO) cycle?

Accepted Answer

A)  Carbon nuclei are split 3 ways to make helium nuclei. 
B)  Carbon and oxygen combine to form nitrogen, which produces energy. 
C)  Carbon and nitrogen combine to form oxygen and energy. 
D)  Four hydrogen nuclei combine to form one helium nucleus and energy. 
A)  Carbon nuclei are split 3 ways to make helium nuclei. 
B)  Carbon and oxygen combine to form nitrogen, which produces energy. 
C)  Carbon and nitrogen combine to form oxygen and energy. 
D)  Four hydrogen nuclei combine to form one helium nucleus and energy.

Question 10

In which way are protostars different from main-sequence stars of the same mass?

Accepted Answer

A)  Protostars are smaller than main-sequence stars. 
B)  Protostars are hotter than main-sequence stars. 
C)  Protostars have a different energy source from main-sequence stars. 
D)  Protostars have longer lifetimes than main-sequence stars. 
A)  Protostars are smaller than main-sequence stars. 
B)  Protostars are hotter than main-sequence stars. 
C)  Protostars have a different energy source from main-sequence stars. 
D)  Protostars have longer lifetimes than main-sequence stars.

Question 11

Parts of a stable molecular cloud can collapse to form stars if a ____________________ passes through it.

Accepted Answer

The answer of Parts of a stable molecular cloud can...

Question 12

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 13

What is the most dominant type of energy transport in the cores of most stars?

Accepted Answer

A)  conduction 
B)  radiation 
C)  convection 
D)  nuclear fusion 
A)  conduction 
B)  radiation 
C)  convection 
D)  nuclear fusion

Question 14

Nuclear fusion in stars is controlled by the dependence of density on mass.

Accepted Answer

A) True 
 B)False

Question 15

Where are stars born?

Accepted Answer

A)  reflection nebulae 
B)  dense molecular clouds 
C)  HII regions 
D)  the intercloud medium 
A)  reflection nebulae 
B)  dense molecular clouds 
C)  HII regions 
D)  the intercloud medium

Question 16

The thermal motions of the atoms in a gas cloud can make it collapse to form a protostar.

Accepted Answer

A) True 
 B)False

Question 17

Hydrostatic equilibrium refers to the balance between weight and pressure.

Accepted Answer

A) True 
 B)False

Question 18

Which of the following are small dark nebulae about 1 light-year in diameter, with masses from 10 to 1,000 solar masses?

Accepted Answer

A)  HII regions 
B)  emission nebulae 
C)  Bok globules 
D)  reflection nebulae 
A)  HII regions 
B)  emission nebulae 
C)  Bok globules 
D)  reflection nebulae

Question 19

What would happen if the nuclear reactions in a star began to produce too little energy?

Accepted Answer

A)  The star would expand. 
B)  The star would explode. 
C)  The star would contract. 
D)  Nothing would happen. 
A)  The star would expand. 
B)  The star would explode. 
C)  The star would contract. 
D)  Nothing would happen.

Question 20

What characteristic of a star primarily determines its location on the main sequence?

Accepted Answer

A)  age 
B)  distance from the galactic centre 
C)  mass 
D)  radius 
A)  age 
B)  distance from the galactic centre 
C)  mass 
D)  radius

-Refer to the H-R diagram. Which point represents a star in which the proton-proton chain is occurring?

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.

HII regions are found near stars cooler than 25,000 K because large amounts of ultraviolet photons would totally destroy the hydrogen atoms in the gas.

Upon observing a nebula, you discover that many stars are surrounded by disks of gas and dust. What can you conclude about these stars?

Which of the following factors explain why infrared telescopes are used to observe protostars?

____________________ is the resistance of a gas to the flow of radiation.

Under what conditions might interstellar gas clouds collapse to form stars?

-The Sun has an expected main-sequence lifetime of about 10 billion years. About how long would a 2-solar-mass star stay on the main sequence?

What happens in the carbon-nitrogen-oxygen (CNO) cycle?

In which way are protostars different from main-sequence stars of the same mass?

Parts of a stable molecular cloud can collapse to form stars if a ____________________ passes through it.

What is opacity?

What is the most dominant type of energy transport in the cores of most stars?

Nuclear fusion in stars is controlled by the dependence of density on mass.

Where are stars born?

The thermal motions of the atoms in a gas cloud can make it collapse to form a protostar.

Hydrostatic equilibrium refers to the balance between weight and pressure.

Which of the following are small dark nebulae about 1 light-year in diameter, with masses from 10 to 1,000 solar masses?

What would happen if the nuclear reactions in a star began to produce too little energy?

What characteristic of a star primarily determines its location on the main sequence?

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

-Refer to the H-R diagram. Which point represents a star in which the proton-proton chain is occurring?

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.

HII regions are found near stars cooler than 25,000 K because large amounts of ultraviolet photons would totally destroy the hydrogen atoms in the gas.

Upon observing a nebula, you discover that many stars are surrounded by disks of gas and dust. What can you conclude about these stars?

Which of the following factors explain why infrared telescopes are used to observe protostars?

____________________ is the resistance of a gas to the flow of radiation.

Under what conditions might interstellar gas clouds collapse to form stars?

-The Sun has an expected main-sequence lifetime of about 10 billion years. About how long would a 2-solar-mass star stay on the main sequence?

What happens in the carbon-nitrogen-oxygen (CNO) cycle?

In which way are protostars different from main-sequence stars of the same mass?

Parts of a stable molecular cloud can collapse to form stars if a ____________________ passes through it.

What is opacity?

What is the most dominant type of energy transport in the cores of most stars?

Nuclear fusion in stars is controlled by the dependence of density on mass.

Where are stars born?

The thermal motions of the atoms in a gas cloud can make it collapse to form a protostar.

Hydrostatic equilibrium refers to the balance between weight and pressure.

Which of the following are small dark nebulae about 1 light-year in diameter, with masses from 10 to 1,000 solar masses?

What would happen if the nuclear reactions in a star began to produce too little energy?

What characteristic of a star primarily determines its location on the main sequence?

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