Question 1

What happens to the wavelength of light as it travels outward through the gravitational field of a planet or star so that the field becomes less strong?

Accepted Answer

A)  The wavelength stays the same, but the intensity of the light decreases. 
B)  The wavelength decreases. 
C)  The wavelength stays the same, but the energy of each photon decreases. 
D)  The wavelength increases. 
A)  The wavelength stays the same, but the intensity of the light decreases. 
B)  The wavelength decreases. 
C)  The wavelength stays the same, but the energy of each photon decreases. 
D)  The wavelength increases.

Question 2

The great breakthrough in understanding the nature of pulsars was the:

Accepted Answer

A)  discovery of a pulsar in the middle of the Crab Nebula. 
B)  realization that pulsars were found only in the galactic plane. 
C)  connection between pulsars and variable stars. 
D)  discovery that all pulsars have periods that are multiples of a universal pulsar period. 
A)  discovery of a pulsar in the middle of the Crab Nebula. 
B)  realization that pulsars were found only in the galactic plane. 
C)  connection between pulsars and variable stars. 
D)  discovery that all pulsars have periods that are multiples of a universal pulsar period.

Question 3

Expansion under high pressure and temperature results in gas from the accretion disk being propelled away from the black hole as jets.What direction do these jets take?

Accepted Answer

A)  They can take any direction except the equatorial plane, which is blocked by the accretion disk. 
B)  They originate from hot spots at middle latitudes north and south of the equatorial disk. 
C)  They move out along the spin axes. 
D)  They move out along the magnetic axes. 
A)  They can take any direction except the equatorial plane, which is blocked by the accretion disk. 
B)  They originate from hot spots at middle latitudes north and south of the equatorial disk. 
C)  They move out along the spin axes. 
D)  They move out along the magnetic axes.

Question 4

What is the observed distribution of the shorter-living gamma-ray bursters in the sky?

Accepted Answer

A)  They are concentrated primarily along the plane of the Milky Way, indicating an origin in the Galaxy. 
B)  They are uniform over the entire sky, indicating an origin at "cosmological" distances. 
C)  They are clumpy but not coinciding with any known galaxy clusters, indicating an origin in a new kind of astronomical object. 
D)  They are clumpy, approximately coinciding with large clusters of galaxies such as the Coma cluster. 
A)  They are concentrated primarily along the plane of the Milky Way, indicating an origin in the Galaxy. 
B)  They are uniform over the entire sky, indicating an origin at "cosmological" distances. 
C)  They are clumpy but not coinciding with any known galaxy clusters, indicating an origin in a new kind of astronomical object. 
D)  They are clumpy, approximately coinciding with large clusters of galaxies such as the Coma cluster.

Question 5

Suppose you were far from a planet that had a very strong gravitational field and you were watching a clock on the surface of the planet.During the time in which your own clock ticks out a time of 1 hour,how much time does the clock on the planet tick out?

Accepted Answer

A)  less than 1 hour (but more than zero) 
B)  no time at all 
C)  more than 1 hour 
D)  exactly 1 hour, the same as yours 
A)  less than 1 hour (but more than zero) 
B)  no time at all 
C)  more than 1 hour 
D)  exactly 1 hour, the same as yours

Question 6

In the process of helium shell fusion in a low-mass star near the end of its life,the star moves upward and to the right on the asymptotic giant branch of the Hertzsprung-Russell diagram.In this process,the star is:

Accepted Answer

A)  contracting, cooling, and hence becoming less luminous. 
B)  expanding, heating up, and becoming more luminous. 
C)  contracting, becoming hotter, and becoming much less luminous. 
D)  expanding, cooling, and becoming more luminous. 
A)  contracting, cooling, and hence becoming less luminous. 
B)  expanding, heating up, and becoming more luminous. 
C)  contracting, becoming hotter, and becoming much less luminous. 
D)  expanding, cooling, and becoming more luminous.

Question 7

The mechanism that gives rise to the phenomenon of the nova is:

Accepted Answer

A)  the impact and subsequent explosion of a large comet nucleus on a star's surface. 
B)  material falling into a black hole and being condensed to the point where a thermonuclear explosion is produced. 
C)  the complete disintegration of a massive star due to a runaway thermonuclear explosion in the star's interior. 
D)  matter from a companion star falling onto a white dwarf in a close binary system, eventually causing a nuclear explosion on the dwarf's surface. 
A)  the impact and subsequent explosion of a large comet nucleus on a star's surface. 
B)  material falling into a black hole and being condensed to the point where a thermonuclear explosion is produced. 
C)  the complete disintegration of a massive star due to a runaway thermonuclear explosion in the star's interior. 
D)  matter from a companion star falling onto a white dwarf in a close binary system, eventually causing a nuclear explosion on the dwarf's surface.

Question 8

A planetary nebula is a(n):

Accepted Answer

A)  contracting spherical cloud of gas surrounding a newly formed star in which planets are forming. 
B)  expanding gas shell surrounding a hot, burned-out stellar core. 
C)  disk-shaped nebula of dust and gas around a relatively young star, from which planets will eventually form. 
D)  nebula caused by the supernova explosion of a massive star. 
A)  contracting spherical cloud of gas surrounding a newly formed star in which planets are forming. 
B)  expanding gas shell surrounding a hot, burned-out stellar core. 
C)  disk-shaped nebula of dust and gas around a relatively young star, from which planets will eventually form. 
D)  nebula caused by the supernova explosion of a massive star.

Question 9

Which statement about starquakes is CORRECT?

Accepted Answer

A)  Starquakes are the cause of glitches in pulsar signals. 
B)  Starquakes are caused by stresses in the crusts of neutron stars that form close binary systems and exert tremendous forces on each other. 
C)  Starquakes are caused by stresses in the crusts of magnetars due to their enormous magnetic fields. 
D)  Starquakes cause rents in the crust of a neutron star and allow gamma rays and X-rays to escape from the interior, like the coronal holes in the Sun's atmosphere. 
A)  Starquakes are the cause of glitches in pulsar signals. 
B)  Starquakes are caused by stresses in the crusts of neutron stars that form close binary systems and exert tremendous forces on each other. 
C)  Starquakes are caused by stresses in the crusts of magnetars due to their enormous magnetic fields. 
D)  Starquakes cause rents in the crust of a neutron star and allow gamma rays and X-rays to escape from the interior, like the coronal holes in the Sun's atmosphere.

Question 10

Neutron stars are believed to be created by:

Accepted Answer

A)  all types of supernovae. 
B)  type Ia supernovae, that is, exploding white dwarfs. 
C)  explosions of main-sequence stars. 
D)  type II supernovae, that is, explosions of high-mass stars. 
A)  all types of supernovae. 
B)  type Ia supernovae, that is, exploding white dwarfs. 
C)  explosions of main-sequence stars. 
D)  type II supernovae, that is, explosions of high-mass stars.

Question 11

In a TV tube,the picture is created by a beam of electrons that travels down the tube at a very high speed.What is the mass of one of these electrons,compared with an electron at rest?

Accepted Answer

A)  The mass of an electron is measured to be the same regardless of how fast it is moving. 
B)  The moving electron appears to have a smaller mass. 
C)  The electron appears to have a greater mass if you are in front of the tube (electrons approaching you) and a smaller mass if you are standing behind the tube (electrons moving away from you). 
D)  The moving electron appears to have a greater mass. 
A)  The mass of an electron is measured to be the same regardless of how fast it is moving. 
B)  The moving electron appears to have a smaller mass. 
C)  The electron appears to have a greater mass if you are in front of the tube (electrons approaching you) and a smaller mass if you are standing behind the tube (electrons moving away from you). 
D)  The moving electron appears to have a greater mass.

Question 12

What is the Schwarzschild radius of a black hole?

Accepted Answer

A)  the distance from the black hole's singularity to the point where any object entering will gain energy before leaving again 
B)  the distance from the black hole's singularity to the point where nothing can escape from the black hole 
C)  the distance from the black hole's singularity to the point where the X-rays are seen to originate 
D)  the radius of the black hole's singularity 
A)  the distance from the black hole's singularity to the point where any object entering will gain energy before leaving again 
B)  the distance from the black hole's singularity to the point where nothing can escape from the black hole 
C)  the distance from the black hole's singularity to the point where the X-rays are seen to originate 
D)  the radius of the black hole's singularity

Question 13

What physical theory has been developed to describe adequately the details of what happens inside a black hole?

Accepted Answer

A)  general relativity 
B)  quantum theory 
C)  electromagnetism 
D)  None of the answers is correct. 
A)  general relativity 
B)  quantum theory 
C)  electromagnetism 
D)  None of the answers is correct.

Question 14

If nothing can ever leave a black hole,can the mass of a black hole ever decrease?

Accepted Answer

A)  no 
B)  yes, if antiparticles enter a black hole and annihilate with matter already inside the black hole 
C)  yes, if the matter inside the black hole is radioactive (e.g., uranium), allowing their decay products-alpha particles, electrons, and gamma rays-to constantly leave the black hole 
D)  yes, if particle-antiparticle pairs are created outside the event horizon out of gravitational energy from the black hole and one particle enters the event horizon while the other escapes 
A)  no 
B)  yes, if antiparticles enter a black hole and annihilate with matter already inside the black hole 
C)  yes, if the matter inside the black hole is radioactive (e.g., uranium), allowing their decay products-alpha particles, electrons, and gamma rays-to constantly leave the black hole 
D)  yes, if particle-antiparticle pairs are created outside the event horizon out of gravitational energy from the black hole and one particle enters the event horizon while the other escapes

Question 15

In which location would a clock run at its fastest rate?

Accepted Answer

A)  empty space 
B)  Earth's surface 
C)  Jupiter's atmosphere 
D)  a "weightless" environment on the Space Shuttle in orbit around Earth 
A)  empty space 
B)  Earth's surface 
C)  Jupiter's atmosphere 
D)  a "weightless" environment on the Space Shuttle in orbit around Earth

Question 16

We have seen that electron degeneracy occurs when the carbon core of a white dwarf becomes dense enough.We have also seen that neutron degeneracy occurs when a neutron star becomes dense enough.Why do you suppose we do not find "proton degeneracy" in some density range between electron and neutron degeneracy?

Accepted Answer

A)  These degeneracies can occur only for neutral particles, and protons carry an electric charge. 
B)  The pressure at which the electron degeneracy is overcome (so that the core collapses) is also sufficient to combine electrons and protons to form neutrons. Thus, most protons disappear when the electron degeneracy ends. 
C)  Protons are too large and heavy to exert degeneracy pressure. This concept applies only to smaller, lighter particles like electrons. 
D)  Protons are not governed by the Pauli exclusion principle, as are electrons and neutrons. 
A)  These degeneracies can occur only for neutral particles, and protons carry an electric charge. 
B)  The pressure at which the electron degeneracy is overcome (so that the core collapses) is also sufficient to combine electrons and protons to form neutrons. Thus, most protons disappear when the electron degeneracy ends. 
C)  Protons are too large and heavy to exert degeneracy pressure. This concept applies only to smaller, lighter particles like electrons. 
D)  Protons are not governed by the Pauli exclusion principle, as are electrons and neutrons.

Question 17

What is the typical duration of a gamma-ray burst?

Accepted Answer

A)  several days, indicating a size much smaller than the distance from the Earth to the nearest star beyond the Sun 
B)  less than a couple of minutes, indicating a source smaller than Mercury's orbit 
C)  up to about 1 hour, indicating a source less than half the size of the solar system 
D)  several hours, indicating a source somewhat larger than the solar system 
A)  several days, indicating a size much smaller than the distance from the Earth to the nearest star beyond the Sun 
B)  less than a couple of minutes, indicating a source smaller than Mercury's orbit 
C)  up to about 1 hour, indicating a source less than half the size of the solar system 
D)  several hours, indicating a source somewhat larger than the solar system

Question 18

The period of pulsation for most pulsars is in the range between:

Accepted Answer

A)  1/1000 second and a few seconds. 
B)  10-⁶ and 10-³ second. 
C)  minutes to tens of hours. 
D)  many hours to a few days. 
A)  1/1000 second and a few seconds. 
B)  10-⁶ and 10-³ second. 
C)  minutes to tens of hours. 
D)  many hours to a few days.

Question 19

In the language of general relativity,what we usually call "gravitational force" is described in terms of:

Accepted Answer

A)  time dilation. 
B)  length contraction. 
C)  gravitational redshift. 
D)  the curvature of spacetime. 
A)  time dilation. 
B)  length contraction. 
C)  gravitational redshift. 
D)  the curvature of spacetime.

Question 20

Type II supernovae show prominent lines of hydrogen in their spectra,whereas hydrogen lines are absent in spectra of Type Ia supernovae.Explain.(Hint: Think about the type of star that gives rise to each of the two types of supernova.)

Accepted Answer

A)  Massive stars contain large amounts of hydrogen, whereas white dwarfs are mostly carbon and oxygen. 
B)  White dwarfs have a thick surface layer of hydrogen, whereas neutron stars contain no hydrogen at all. 
C)  Massive stars have fused all their hydrogen into heavier elements, whereas low-mass stars still have large hydrogen-rich envelopes. 
D)  Massive stars contain large amounts of hydrogen, whereas neutron stars contain no hydrogen at all. 
A)  Massive stars contain large amounts of hydrogen, whereas white dwarfs are mostly carbon and oxygen. 
B)  White dwarfs have a thick surface layer of hydrogen, whereas neutron stars contain no hydrogen at all. 
C)  Massive stars have fused all their hydrogen into heavier elements, whereas low-mass stars still have large hydrogen-rich envelopes. 
D)  Massive stars contain large amounts of hydrogen, whereas neutron stars contain no hydrogen at all.

What happens to the wavelength of light as it travels outward through the gravitational field of a planet or star so that the field becomes less strong?

The great breakthrough in understanding the nature of pulsars was the:

Expansion under high pressure and temperature results in gas from the accretion disk being propelled away from the black hole as jets.What direction do these jets take?

What is the observed distribution of the shorter-living gamma-ray bursters in the sky?

Suppose you were far from a planet that had a very strong gravitational field and you were watching a clock on the surface of the planet.During the time in which your own clock ticks out a time of 1 hour,how much time does the clock on the planet tick out?

In the process of helium shell fusion in a low-mass star near the end of its life,the star moves upward and to the right on the asymptotic giant branch of the Hertzsprung-Russell diagram.In this process,the star is:

The mechanism that gives rise to the phenomenon of the nova is:

A planetary nebula is a(n):

Which statement about starquakes is CORRECT?

Neutron stars are believed to be created by:

In a TV tube,the picture is created by a beam of electrons that travels down the tube at a very high speed.What is the mass of one of these electrons,compared with an electron at rest?

What is the Schwarzschild radius of a black hole?

What physical theory has been developed to describe adequately the details of what happens inside a black hole?

If nothing can ever leave a black hole,can the mass of a black hole ever decrease?

In which location would a clock run at its fastest rate?

What is the typical duration of a gamma-ray burst?

The period of pulsation for most pulsars is in the range between:

In the language of general relativity,what we usually call "gravitational force" is described in terms of:

Type II supernovae show prominent lines of hydrogen in their spectra,whereas hydrogen lines are absent in spectra of Type Ia supernovae.Explain.(Hint: Think about the type of star that gives rise to each of the two types of supernova.)

Discovering the Night Sky

Gravitation and the Waltz of the Planets

Light and Telescopes

Formation of the Solar System and Other Planetary Systems

Exoplanets

The Terrestrial Planets and Their Moons

The Outer Planets and Their Moons

Vagabonds of the Solar System

The Sun: Our Extraordinary Ordinary Star

Characterizing Stars

The Lives of the Stars From Birth Through Middle Age

The Galaxies

Cosmology

Astrobiology

Filters

Exam 12: The Deaths and Remnants of Stars

What happens to the wavelength of light as it travels outward through the gravitational field of a planet or star so that the field becomes less strong?

The great breakthrough in understanding the nature of pulsars was the:

Expansion under high pressure and temperature results in gas from the accretion disk being propelled away from the black hole as jets.What direction do these jets take?

What is the observed distribution of the shorter-living gamma-ray bursters in the sky?

Suppose you were far from a planet that had a very strong gravitational field and you were watching a clock on the surface of the planet.During the time in which your own clock ticks out a time of 1 hour,how much time does the clock on the planet tick out?

In the process of helium shell fusion in a low-mass star near the end of its life,the star moves upward and to the right on the asymptotic giant branch of the Hertzsprung-Russell diagram.In this process,the star is:

The mechanism that gives rise to the phenomenon of the nova is:

A planetary nebula is a(n):

Which statement about starquakes is CORRECT?

Neutron stars are believed to be created by:

In a TV tube,the picture is created by a beam of electrons that travels down the tube at a very high speed.What is the mass of one of these electrons,compared with an electron at rest?

What is the Schwarzschild radius of a black hole?

What physical theory has been developed to describe adequately the details of what happens inside a black hole?

If nothing can ever leave a black hole,can the mass of a black hole ever decrease?

In which location would a clock run at its fastest rate?

What is the typical duration of a gamma-ray burst?

The period of pulsation for most pulsars is in the range between:

In the language of general relativity,what we usually call "gravitational force" is described in terms of:

Type II supernovae show prominent lines of hydrogen in their spectra,whereas hydrogen lines are absent in spectra of Type Ia supernovae.Explain.(Hint: Think about the type of star that gives rise to each of the two types of supernova.)

Discovering the Night Sky

Gravitation and the Waltz of the Planets

Light and Telescopes

Formation of the Solar System and Other Planetary Systems

Exoplanets

The Terrestrial Planets and Their Moons

The Outer Planets and Their Moons

Vagabonds of the Solar System

The Sun: Our Extraordinary Ordinary Star

Characterizing Stars

The Lives of the Stars From Birth Through Middle Age

The Galaxies

Cosmology

Astrobiology

Filters