Question 1

The estimated rate at which supernova explosions occur in a spiral galaxy such as our own is about once every _____ years.

Accepted Answer

A)   5
B)   300
C)   3000
D)   20E) C) and D)
F) B) and D)

Question 2

What is a Kerr black hole?

Accepted Answer

A)   a nonrotating black hole
B)   a rotating black hole
C)   an uncharged black hole
D)   a hypothetical zero-mass black holeE) None of the above
F) A) and D)

Question 3

You toss a green ball toward a Schwarzschild black hole.What will NOT be observed as the ball accelerates toward the event horizon?

Accepted Answer

A)   The ball will appear green, then yellow, then red.
B)   The ball will become elongated.
C)   The ball's lateral size will decrease.
D)   The ball will spin faster and faster.E) B) and D)
F) A) and C)

Question 4

The detection of neutrinos from supernova SN 1987A occurred 3 hours before the detection of the burst of visible light.What caused this time lag?

Accepted Answer

A)   Neutrinos travel faster in a vacuum than light does.
B)   The space between the supernova and Earth is not a perfect vacuum but is filled with very rarified gas and dust, which impedes the passage of light (very slightly)  but not of neutrinos.
C)   The neutrinos and the light were produced at the same time, but the light bounced back and forth between the core and the outer layers several times before these layers expanded to the point that they became transparent.
D)   The neutrinos were produced earlier (when the core collapsed)  and the light was produced 3 hours later (when the shock wave reached the outer layers) .E) A) and D)
F) C) and D)

Question 5

What is the main observational difference between a Type Ia and a Type II supernova?

Accepted Answer

A)   Hydrogen lines are prominent in the spectrum of a Type Ia supernova but absent in that of a Type II.
B)   The spectrum of a Type II supernova shows strong lines of both hydrogen and helium, whereas that of a Type Ia shows only hydrogen.
C)   The spectrum of a Type Ia supernova shows strong lines of both hydrogen and helium, whereas that of a Type II shows only hydrogen.
D)   Hydrogen lines are prominent in the spectrum of a Type II supernova but absent in that of a Type Ia.E) B) and D)
F) A) and B)

Question 6

From observations of supernova explosions in distant galaxies,it is predicted that there should be about five supernovae per century in our Galaxy,whereas we have seen only about one every 300 years from Earth.Explain.

Accepted Answer

A)   The majority of supernovae produce no visible light, only radio and X-ray radiation, which we have been able to observe from Earth for only the past three decades.
B)   Most supernovae occur in the galactic plane, where interstellar dust has hidden them from our view from Earth.
C)   Most supernovae occur in the Milky Way and can be seen only from the southern hemisphere, where there have been very few observers until recently.
D)   The majority of stars in the Galaxy are old, well beyond the supernova stage of evolution.E) C) and D)
F) A) and D)

Question 7

The escape velocity at the event horizon around a black hole is;

Accepted Answer

A)   infinite.
B)   equal to the speed of light.
C)   much less than the speed of light.
D)   just under the speed of light.E) All of the above
F) A) and D)

Question 8

Each of the following statements about white dwarfs is true EXCEPT ONE.Which is the exception?

Accepted Answer

A)   They generate energy by core fusion of carbon and hydrogen to produce oxygen.
B)   Novae are generated by white dwarfs in close binary systems.
C)   A white dwarf can be the source of more than one nova.
D)   The Chandrasekhar limit restricts the maximum mass of a white dwarf.E) A) and B)
F) A) and C)

Question 9

What physical process provides the energy for the ejection of a planetary nebula from a low-mass star?

Accepted Answer

A)   transfer of hydrogen-rich material onto the surface of a white dwarf from its companion in a binary star system
B)   helium shell flashes in the helium fusion shell
C)   core collapse and the ensuing shock wave
D)   collision with another starE) A) and B)
F) A) and C)

Question 10

There is a mass limit for a star in the white-dwarf phase,the Chandrasakhar limit,beyond which the electron degeneracy pressure can no longer support the star against its own gravity.This limit is:

Accepted Answer

A)   0.2 solar mass.
B)   30 solar masses.
C)   1.4 solar masses.
D)   14 solar masses.E) None of the above
F) All of the above

Question 11

In a binary star system,an unseen component is found to have 8 solar masses.It would be visible if the system were a normal star,so it must be a collapsed object.Theoretical considerations tell us that it must be a:

Accepted Answer

A)   black hole.
B)   neutron star.
C)   white dwarf.
D)   brown dwarf.E) A) and D)
F) A) and C)

Question 12

The difference between a nova and an X-ray burst is that a nova involves an explosion on the surface of a _____,whereas an X-ray burst involves a(n) _____.

Accepted Answer

A)   white dwarf; explosion on the surface of a neutron star
B)   neutron star; explosion on the surface of a white dwarf
C)   white dwarf; explosion on the surface of the white dwarf
D)   neutron star; complete collapse of a neutron star to form a black holeE) A) and C)
F) None of the above

Question 13

The first pulsar was detected with:

Accepted Answer

A)   Galileo's telescope.
B)   the infrared satellite IRAS.
C)   a radio telescope being used by Cambridge University.
D)   the 200-inch telescope at Mount Palomar.E) All of the above
F) A) and D)

Question 14

In a Hubble Space Telescope search for evidence of supermassive black holes in about 30 nearby galaxies,evidence was found that:

Accepted Answer

A)   only one galaxy, the Milky Way Galaxy, contains a supermassive black hole.
B)   no galaxies in the vicinity of Earth contain a supermassive black hole at their centers.
C)   almost all galaxies contain supermassive black holes.
D)   only spiral galaxies contain supermassive black holes.E) A) and D)
F) A) and C)

Question 15

Our study of Supernova 1987A and our study of the Sun have at least one aspect in common,namely that:

Accepted Answer

A)   it was not as bright as it was predicted to be theoretically.
B)   magnetic effects provided much of our information.
C)   the information provided by non-visible radiation contradicted that from visible observations.
D)   the most current information about the core was carried by neutrinos.E) B) and C)
F) All of the above

Exam 12: The Deaths and Remnants of Stars

The estimated rate at which supernova explosions occur in a spiral galaxy such as our own is about once every _____ years.

Correct Answer
verified

What physical process provides the energy for the ejection of a planetary nebula from a low-mass star?

Correct Answer
verified

The escape velocity at the event horizon around a black hole is;

Correct Answer
verified

The first pulsar was detected with:

Correct Answer
verified

Our study of Supernova 1987A and our study of the Sun have at least one aspect in common,namely that:

Correct Answer
verified

What is the main observational difference between a Type Ia and a Type II supernova?

Correct Answer
verified

There is a mass limit for a star in the white-dwarf phase,the Chandrasakhar limit,beyond which the electron degeneracy pressure can no longer support the star against its own gravity.This limit is:

Correct Answer
verified

The difference between a nova and an X-ray burst is that a nova involves an explosion on the surface of a _,whereas an X-ray burst involves a(n) _.

Correct Answer
verified

What is a Kerr black hole?

Correct Answer
verified

Each of the following statements about white dwarfs is true EXCEPT ONE.Which is the exception?

Correct Answer
verified

In a Hubble Space Telescope search for evidence of supermassive black holes in about 30 nearby galaxies,evidence was found that:

Correct Answer
verified

The detection of neutrinos from supernova SN 1987A occurred 3 hours before the detection of the burst of visible light.What caused this time lag?

Correct Answer
verified

You toss a green ball toward a Schwarzschild black hole.What will NOT be observed as the ball accelerates toward the event horizon?

Correct Answer
verified

From observations of supernova explosions in distant galaxies,it is predicted that there should be about five supernovae per century in our Galaxy,whereas we have seen only about one every 300 years from Earth.Explain.

Correct Answer
verified

In a binary star system,an unseen component is found to have 8 solar masses.It would be visible if the system were a normal star,so it must be a collapsed object.Theoretical considerations tell us that it must be a:

Correct Answer
verified

Exam 12: The Deaths and Remnants of Stars

The estimated rate at which supernova explosions occur in a spiral galaxy such as our own is about once every _____ years.

Correct AnswerverifiedShow Answer

What physical process provides the energy for the ejection of a planetary nebula from a low-mass star?

Correct AnswerverifiedShow Answer

The escape velocity at the event horizon around a black hole is;

Correct AnswerverifiedShow Answer

The first pulsar was detected with:

Correct AnswerverifiedShow Answer

Our study of Supernova 1987A and our study of the Sun have at least one aspect in common,namely that:

Correct AnswerverifiedShow Answer

What is the main observational difference between a Type Ia and a Type II supernova?

Correct AnswerverifiedShow Answer

There is a mass limit for a star in the white-dwarf phase,the Chandrasakhar limit,beyond which the electron degeneracy pressure can no longer support the star against its own gravity.This limit is:

Correct AnswerverifiedShow Answer

The difference between a nova and an X-ray burst is that a nova involves an explosion on the surface of a _____,whereas an X-ray burst involves a(n) _____.

Correct AnswerverifiedShow Answer

What is a Kerr black hole?

Correct AnswerverifiedShow Answer

Each of the following statements about white dwarfs is true EXCEPT ONE.Which is the exception?

Correct AnswerverifiedShow Answer

In a Hubble Space Telescope search for evidence of supermassive black holes in about 30 nearby galaxies,evidence was found that:

Correct AnswerverifiedShow Answer

The detection of neutrinos from supernova SN 1987A occurred 3 hours before the detection of the burst of visible light.What caused this time lag?

Correct AnswerverifiedShow Answer

You toss a green ball toward a Schwarzschild black hole.What will NOT be observed as the ball accelerates toward the event horizon?

Correct AnswerverifiedShow Answer

From observations of supernova explosions in distant galaxies,it is predicted that there should be about five supernovae per century in our Galaxy,whereas we have seen only about one every 300 years from Earth.Explain.

Correct AnswerverifiedShow Answer

In a binary star system,an unseen component is found to have 8 solar masses.It would be visible if the system were a normal star,so it must be a collapsed object.Theoretical considerations tell us that it must be a:

Correct AnswerverifiedShow Answer

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The difference between a nova and an X-ray burst is that a nova involves an explosion on the surface of a _,whereas an X-ray burst involves a(n) _.

Correct Answer
verified

Correct Answer
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Correct Answer
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Correct Answer
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