Question 1

Recent observations reveal that the outer parts of novae are composed of:

Accepted Answer

A)  smooth shells of expanding gas. 
B)  shells that originate from bipolar jets. 
C)  thousands of clumps of gas. 
D)  warped rings of gas and dust. 
A)  smooth shells of expanding gas. 
B)  shells that originate from bipolar jets. 
C)  thousands of clumps of gas. 
D)  warped rings of gas and dust.

Question 2

A white dwarf is about the same size as

Accepted Answer

A)  the Sun. 
B)  Earth. 
C)  the total solar system. 
D)  a major city. 
A)  the Sun. 
B)  Earth. 
C)  the total solar system. 
D)  a major city.

Question 3

Where would you look for an event horizon?

Accepted Answer

A)  in the photosphere of a star (e.g., the Sun) 
B)  in the magnetosphere of a neutron star 
C)  at the edge of the visible universe 
D)  near a black hole 
A)  in the photosphere of a star (e.g., the Sun) 
B)  in the magnetosphere of a neutron star 
C)  at the edge of the visible universe 
D)  near a black hole

Question 4

A clock with a luminous dial is moving toward you at a speed that is a large fraction of the speed of light.What will you observe?

Accepted Answer

A)  The light emitted by the clock will be shifted toward longer wavelengths compared to those seen by an observer moving with the clock. 
B)  The light from the clock is approaching you at speed c. 
C)  The clock runs fast compared to an identical clock at rest in your hand. 
D)  The clock appears thicker, front to back, than the identical clock in your hand. 
A)  The light emitted by the clock will be shifted toward longer wavelengths compared to those seen by an observer moving with the clock. 
B)  The light from the clock is approaching you at speed c. 
C)  The clock runs fast compared to an identical clock at rest in your hand. 
D)  The clock appears thicker, front to back, than the identical clock in your hand.

Question 5

What fraction of its mass does a main-sequence star of 25 solar masses eject into space during its lifetime?

Accepted Answer

A)  almost all of it, greater than 80% 
B)  only a small fraction, about 1/100 
C)  between 1/4 and 1/2 
D)  only its outer atmosphere, less than 1 part in 10⁴ 
A)  almost all of it, greater than 80% 
B)  only a small fraction, about 1/100 
C)  between 1/4 and 1/2 
D)  only its outer atmosphere, less than 1 part in 10⁴

Question 6

In the study of neutron stars,what is a glitch?

Accepted Answer

A)  a sudden change in the rotation rate of the neutron star 
B)  a change in the pulse period of a neutron star due to the gravitational effect of an orbiting planet 
C)  a sudden pulse of light from the neutron star 
D)  a collision between two neutron stars 
A)  a sudden change in the rotation rate of the neutron star 
B)  a change in the pulse period of a neutron star due to the gravitational effect of an orbiting planet 
C)  a sudden pulse of light from the neutron star 
D)  a collision between two neutron stars

Question 7

The final remnant of the evolution of a red giant star that has ejected a planetary nebula is a:

Accepted Answer

A)  protostar. 
B)  blue supergiant. 
C)  white dwarf. 
D)  supernova. 
A)  protostar. 
B)  blue supergiant. 
C)  white dwarf. 
D)  supernova.

Question 8

The duration of the oxygen-fusing stage in the core of a massive star is considerably shorter than the duration of the carbon-fusing stage.One main reason for this is that:

Accepted Answer

A)  carbon is a solid, while oxygen is a gas. 
B)  oxygen fusion does not begin until the contracting core has reached a higher temperature than the temperature at which carbon fusion is possible. 
C)  the electron degeneracy inhibits the carbon reaction, but it has been removed by the time oxygen fusion begins. 
D)  there are more fusion shells surrounding the oxygen fusion core than there are around the carbon fusion core. The shells prevent the escape of oxygen before it can fuse. 
A)  carbon is a solid, while oxygen is a gas. 
B)  oxygen fusion does not begin until the contracting core has reached a higher temperature than the temperature at which carbon fusion is possible. 
C)  the electron degeneracy inhibits the carbon reaction, but it has been removed by the time oxygen fusion begins. 
D)  there are more fusion shells surrounding the oxygen fusion core than there are around the carbon fusion core. The shells prevent the escape of oxygen before it can fuse.

Question 9

Which type of star or stellar remnant can have a mass no larger than about 1.4 times the mass of the Sun,or else it will collapse under its own gravity?

Accepted Answer

A)  a red giant 
B)  a black hole 
C)  a neutron star 
D)  a white dwarf 
A)  a red giant 
B)  a black hole 
C)  a neutron star 
D)  a white dwarf

Question 10

Which action will a high-mass star (say,25 times the mass of the Sun)NOT do at or near the end of its life?

Accepted Answer

A)  eject its outer layers and become a neutron star 
B)  convert silicon into iron in its core 
C)  emit copious amounts of neutrinos 
D)  eject its outer layers and become a white dwarf 
A)  eject its outer layers and become a neutron star 
B)  convert silicon into iron in its core 
C)  emit copious amounts of neutrinos 
D)  eject its outer layers and become a white dwarf

Question 11

The Crab Nebula is a nearby example of what type of physical phenomenon?

Accepted Answer

A)  a planetary nebula, a shell of gas leaving an old star 
B)  the remnant of a supernova explosion 
C)  a spiral galaxy, a collection of 100 billion stars 
D)  a gas and dust cloud, the formation region for new stars 
A)  a planetary nebula, a shell of gas leaving an old star 
B)  the remnant of a supernova explosion 
C)  a spiral galaxy, a collection of 100 billion stars 
D)  a gas and dust cloud, the formation region for new stars

Question 12

Which effects have been useful (and successful)in the search for and identification of black holes in the universe?

Accepted Answer

A)  the influence of their intense gravitational field on atoms that are emitting light from the event horizons of the black holes 
B)  their gravitational influence on nearby matter, particularly companion stars 
C)  the effect of their angular momentum, or spin, on nearby matter 
D)  their magnetic fields and the influence of these fields on nearby matter 
A)  the influence of their intense gravitational field on atoms that are emitting light from the event horizons of the black holes 
B)  their gravitational influence on nearby matter, particularly companion stars 
C)  the effect of their angular momentum, or spin, on nearby matter 
D)  their magnetic fields and the influence of these fields on nearby matter

Question 13

Near the end of its life a high-mass star has six active fusion shells surrounding its core.How many did it have when it was on the main sequence?

Accepted Answer

A)  none 
B)  one 
C)  three 
D)  six 
A)  none 
B)  one 
C)  three 
D)  six

Question 14

The rings of material surrounding the SN 1987A supernova remnant glow.In what region of the spectrum would you expect them to emit radiation?

Accepted Answer

A)  The rings are mostly hydrogen, so the Hα line might be expected to be prominent in the resulting spectrum. 
B)  The rings glow because of natural radioactivity, which emits mostly gamma radiation. 
C)  The heavy elements created in the supernova have complex atomic structures that emit a continuous spectrum. 
D)  Only the longest radio waves can penetrate the dust clouds surrounding the supernova remnant. 
A)  The rings are mostly hydrogen, so the Hα line might be expected to be prominent in the resulting spectrum. 
B)  The rings glow because of natural radioactivity, which emits mostly gamma radiation. 
C)  The heavy elements created in the supernova have complex atomic structures that emit a continuous spectrum. 
D)  Only the longest radio waves can penetrate the dust clouds surrounding the supernova remnant.

Question 15

Theoretical physics predicts various types of black holes.Which type is NOT one of them?

Accepted Answer

A)  primordial black holes: masses from a few grams to the mass of a planet 
B)  intermediate mass black holes: hundreds to thousands of solar masses 
C)  supermassive black holes: millions or billions of solar masses 
D)  supercluster black holes: billions of billions of solar masses 
A)  primordial black holes: masses from a few grams to the mass of a planet 
B)  intermediate mass black holes: hundreds to thousands of solar masses 
C)  supermassive black holes: millions or billions of solar masses 
D)  supercluster black holes: billions of billions of solar masses

Question 16

Each of the following statement correctly compares gamma ray bursts with X-ray bursts EXCEPT ONE.Which is the exception?

Accepted Answer

A)  Gamma ray bursts occur only once. X-ray bursts can repeat. 
B)  Gamma ray bursts originate all over the sky. X-ray bursts come mostly from the galactic plane. 
C)  In general, gamma ray bursts carry less energy than X-ray bursts. 
D)  Gamma ray bursts appear to originate at the beginning of a supernova explosion. X-ray bursts original in binary systems. 
A)  Gamma ray bursts occur only once. X-ray bursts can repeat. 
B)  Gamma ray bursts originate all over the sky. X-ray bursts come mostly from the galactic plane. 
C)  In general, gamma ray bursts carry less energy than X-ray bursts. 
D)  Gamma ray bursts appear to originate at the beginning of a supernova explosion. X-ray bursts original in binary systems.

Question 17

Supernova SN 1987A in the Large Magellanic Cloud differed from most other Type II supernovae in being considerably fainter.Explain.

Accepted Answer

A)  The star that exploded was much smaller than a normal Type II supernova. 
B)  The star was surrounded by interstellar gas and dust that partially hid it from view from Earth. 
C)  The star contained considerably more heavy elements than most Type II supernovae, and these elements are believed to have absorbed many of the neutrinos produced in the core collapse. 
D)  The star that exploded was considerably cooler than a normal Type II supernova. 
A)  The star that exploded was much smaller than a normal Type II supernova. 
B)  The star was surrounded by interstellar gas and dust that partially hid it from view from Earth. 
C)  The star contained considerably more heavy elements than most Type II supernovae, and these elements are believed to have absorbed many of the neutrinos produced in the core collapse. 
D)  The star that exploded was considerably cooler than a normal Type II supernova.

Question 18

Cerenkov radiation that was used to detect neutrinos from SN 1987A was produced by:

Accepted Answer

A)  neutrons ejected from nuclei by the neutrinos. 
B)  positive electrons (positrons) traveling faster than the speed of light in water. 
C)  nuclear fusion produced in the detector by neutrinos. 
D)  electrons and antielectrons (positrons) colliding and annihilating. 
A)  neutrons ejected from nuclei by the neutrinos. 
B)  positive electrons (positrons) traveling faster than the speed of light in water. 
C)  nuclear fusion produced in the detector by neutrinos. 
D)  electrons and antielectrons (positrons) colliding and annihilating.

Question 19

Where is the event horizon of a black hole located?

Accepted Answer

A)  the position of maximum X-ray emission 
B)  the singularity 
C)  the outer surface of the ergoregion 
D)  the Schwarzschild radius away from its center 
A)  the position of maximum X-ray emission 
B)  the singularity 
C)  the outer surface of the ergoregion 
D)  the Schwarzschild radius away from its center

Question 20

Two spaceships are traveling past Earth at 90% of the speed of light in opposite directions (i.e.,they are approaching each other).One turns on a searchlight,which is seen by scientists aboard the other.What speed do the scientists measure for this light (c = speed of light in a vacuum)?

Accepted Answer

A)  1.9 c (equal to c + 0.9 c) 
B)  1.8 c (equal to 2 × 0.9 c). 
C)  c 
D)  0.9 c 
A)  1.9 c (equal to c + 0.9 c) 
B)  1.8 c (equal to 2 × 0.9 c). 
C)  c 
D)  0.9 c

Recent observations reveal that the outer parts of novae are composed of:

A white dwarf is about the same size as

Where would you look for an event horizon?

A clock with a luminous dial is moving toward you at a speed that is a large fraction of the speed of light.What will you observe?

What fraction of its mass does a main-sequence star of 25 solar masses eject into space during its lifetime?

In the study of neutron stars,what is a glitch?

The final remnant of the evolution of a red giant star that has ejected a planetary nebula is a:

The duration of the oxygen-fusing stage in the core of a massive star is considerably shorter than the duration of the carbon-fusing stage.One main reason for this is that:

Which type of star or stellar remnant can have a mass no larger than about 1.4 times the mass of the Sun,or else it will collapse under its own gravity?

Which action will a high-mass star (say,25 times the mass of the Sun)NOT do at or near the end of its life?

The Crab Nebula is a nearby example of what type of physical phenomenon?

Which effects have been useful (and successful)in the search for and identification of black holes in the universe?

Near the end of its life a high-mass star has six active fusion shells surrounding its core.How many did it have when it was on the main sequence?

The rings of material surrounding the SN 1987A supernova remnant glow.In what region of the spectrum would you expect them to emit radiation?

Theoretical physics predicts various types of black holes.Which type is NOT one of them?

Each of the following statement correctly compares gamma ray bursts with X-ray bursts EXCEPT ONE.Which is the exception?

Supernova SN 1987A in the Large Magellanic Cloud differed from most other Type II supernovae in being considerably fainter.Explain.

Cerenkov radiation that was used to detect neutrinos from SN 1987A was produced by:

Where is the event horizon of a black hole located?

Two spaceships are traveling past Earth at 90% of the speed of light in opposite directions (i.e.,they are approaching each other).One turns on a searchlight,which is seen by scientists aboard the other.What speed do the scientists measure for this light (c = speed of light in a vacuum)?

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

Recent observations reveal that the outer parts of novae are composed of:

A white dwarf is about the same size as

Where would you look for an event horizon?

A clock with a luminous dial is moving toward you at a speed that is a large fraction of the speed of light.What will you observe?

What fraction of its mass does a main-sequence star of 25 solar masses eject into space during its lifetime?

In the study of neutron stars,what is a glitch?

The final remnant of the evolution of a red giant star that has ejected a planetary nebula is a:

The duration of the oxygen-fusing stage in the core of a massive star is considerably shorter than the duration of the carbon-fusing stage.One main reason for this is that:

Which type of star or stellar remnant can have a mass no larger than about 1.4 times the mass of the Sun,or else it will collapse under its own gravity?

Which action will a high-mass star (say,25 times the mass of the Sun)NOT do at or near the end of its life?

The Crab Nebula is a nearby example of what type of physical phenomenon?

Which effects have been useful (and successful)in the search for and identification of black holes in the universe?

Near the end of its life a high-mass star has six active fusion shells surrounding its core.How many did it have when it was on the main sequence?

The rings of material surrounding the SN 1987A supernova remnant glow.In what region of the spectrum would you expect them to emit radiation?

Theoretical physics predicts various types of black holes.Which type is NOT one of them?

Each of the following statement correctly compares gamma ray bursts with X-ray bursts EXCEPT ONE.Which is the exception?

Supernova SN 1987A in the Large Magellanic Cloud differed from most other Type II supernovae in being considerably fainter.Explain.

Cerenkov radiation that was used to detect neutrinos from SN 1987A was produced by:

Where is the event horizon of a black hole located?

Two spaceships are traveling past Earth at 90% of the speed of light in opposite directions (i.e.,they are approaching each other).One turns on a searchlight,which is seen by scientists aboard the other.What speed do the scientists measure for this light (c = speed of light in a vacuum)?

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