Question 1

The average density of neutron stars approaches:

Accepted Answer

A)   a million times that of normal matter.
B)   a million times that of even a white dwarf.
C)   about 10¹⁷ kg/m³, similar to the density of atomic nuclei.
D)   about 10¹⁸ times that of water.
E)   infinity.

Question 2

Relate escape velocity to the event horizon.

Accepted Answer

At the event horizon around a ...

Question 3

Which of the following can actually escape from inside a black hole's event horizon?

Accepted Answer

A)   neutrinos
B)   electrons
C)   very high energy gamma-rays
D)   gravitons
E)   None of the above

Question 4

A proposed explanation for gamma-ray bursters is:

Accepted Answer

A)   hypernova-making black holes and bi-polar jets.
B)   coalescence of a neutron star binary.
C)   collisions between two white dwarfs.
D)   Both A and B are possible.
E)   All three are possible.

Question 5

The escape speed for a black hole's event horizon is the speed of light.

Accepted Answer

A) True 
 B)False  True

Question 6

A critical difference between millisecond and normal pulsars is that:

Accepted Answer

A)   the millisecond ones are not associated with the galaxy, but scattered everywhere.
B)   the millisecond ones are speeding up, but normal pulsars slow down over time.
C)   the millisecond ones must eventually collapse into black holes.
D)   the millisecond ones all have planets, while normal ones do not.
E)   millisecond ones are only found in globular clusters, while normal ones are not.

Question 7

Contrast the internal structures and properties of neutron stars with white dwarf and main sequence stars.Specifically,what processes in each balance the inward pull of gravity; what are their energy sources; and what are their sizes,densities,and temperatures?

Accepted Answer

Main sequence: Internal structure is hyd...

Question 8

The key to identifying a black hole candidate in a binary system is that:

Accepted Answer

A)   one of the two stars cannot be seen.
B)   the unseen companion in the system must have a sufficiently high mass.
C)   the unseen star is a contact binary.
D)   the system must be a very strong source of radio emissions.
E)   the visible companion must be an evolving main sequence or giant star.

Question 9

Neutron stars do NOT have:

Accepted Answer

A)   masses greater than 1.4 solar masses.
B)   sizes comparable to large cities.
C)   strong magnetic fields.
D)   large surface gravities, compared to the Sun.
E)   rotation periods comparable to the Sun's. E

Question 10

All neutron stars are pulsars,but not all pulsars are neutron stars.

Accepted Answer

A) True 
 B)False

Question 11

Most pulsars have a measured mass of:

Accepted Answer

A)   about 1.4 solar masses.
B)   less than 1.0 solar masses.
C)   between 2 and 4 solar masses.
D)   5.2 solar masses.
E)   greater than 10 solar masses.

Question 12

In what manner have astronomers and physicists made tests to confirm that Einstein's theory of general relativity is actually a proper description of gravitational phenomena?

Accepted Answer

A number of tests have confirmed Einstei...

Question 13

Contrast the space motion of neutron stars with normal stars.Explain.

Accepted Answer

In general,neutron stars are m...

Question 14

With what objects do many of the millisecond pulsars appear to be associated,and what does this tell us about their age?

Accepted Answer

Many lie in globular clusters,which are ...

Question 15

Neutron stars and black holes are formed by:

Accepted Answer

A)   the star formation process.
B)   mass transfer in binary star systems.
C)   novae.
D)   type I supernovae.
E)   type II supernovae.

Question 16

Relate escape speed to event horizon for a black hole.

Accepted Answer

The escape speed allows an object moving...

Question 17

Why do scientists describe the theory of gravity as "incomplete"?

Accepted Answer

A)   It does not incorporate a description of matter on a very small scale.
B)   It does not explain why light bends near a dense object.
C)   It does not agree with the expansion of the universe.
D)   The gravity waves it predicts have not been observed.
E)   It does not explain the effects on time from a massive object.

Question 18

Which of the following are attracted by gravity?

Accepted Answer

A)   antimatter
B)   any object with mass
C)   electromagnetic radiation
D)   neutrinos
E)   All of the above E

Question 19

The density of a neutron star is comparable to the density of an atomic nucleus.

Accepted Answer

A) True 
 B)False

Question 20

Any main sequence star over 25 solar masses will probably retain enough matter in its core after its type II supernova to make a black hole.

Accepted Answer

A) True 
 B)False

Exam 22: Neutron Stars and Black Holes: Strange States of Matter

The average density of neutron stars approaches:

Correct AnswerverifiedShow Answer

Relate escape velocity to the event horizon.

Correct AnswerverifiedAt the event horizon around a ...View AnswerShow Answer

Which of the following can actually escape from inside a black hole's event horizon?

Correct AnswerverifiedShow Answer

A proposed explanation for gamma-ray bursters is:

Correct AnswerverifiedShow Answer

The escape speed for a black hole's event horizon is the speed of light.

Correct AnswerverifiedTrue

A critical difference between millisecond and normal pulsars is that:

Correct AnswerverifiedShow Answer

Contrast the internal structures and properties of neutron stars with white dwarf and main sequence stars.Specifically,what processes in each balance the inward pull of gravity; what are their energy sources; and what are their sizes,densities,and temperatures?

Correct AnswerverifiedMain sequence: Internal structure is hyd...View AnswerShow Answer

The key to identifying a black hole candidate in a binary system is that:

Correct AnswerverifiedShow Answer

Neutron stars do NOT have:

Correct AnswerverifiedE

All neutron stars are pulsars,but not all pulsars are neutron stars.

Correct AnswerverifiedShow Answer

Most pulsars have a measured mass of:

Correct AnswerverifiedShow Answer

In what manner have astronomers and physicists made tests to confirm that Einstein's theory of general relativity is actually a proper description of gravitational phenomena?

Correct AnswerverifiedA number of tests have confirmed Einstei...View AnswerShow Answer

Contrast the space motion of neutron stars with normal stars.Explain.

Correct AnswerverifiedIn general,neutron stars are m...View AnswerShow Answer

With what objects do many of the millisecond pulsars appear to be associated,and what does this tell us about their age?

Correct AnswerverifiedMany lie in globular clusters,which are ...View AnswerShow Answer

Neutron stars and black holes are formed by:

Correct AnswerverifiedShow Answer

Relate escape speed to event horizon for a black hole.

Correct AnswerverifiedThe escape speed allows an object moving...View AnswerShow Answer

Why do scientists describe the theory of gravity as "incomplete"?

Correct AnswerverifiedShow Answer

Which of the following are attracted by gravity?

Correct AnswerverifiedE

The density of a neutron star is comparable to the density of an atomic nucleus.

Correct AnswerverifiedShow Answer

Any main sequence star over 25 solar masses will probably retain enough matter in its core after its type II supernova to make a black hole.

Correct AnswerverifiedShow Answer

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At the event horizon around a ...
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True

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Main sequence: Internal structure is hyd...
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E

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A number of tests have confirmed Einstei...
View Answer

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In general,neutron stars are m...
View Answer

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Many lie in globular clusters,which are ...
View Answer

Correct Answer
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The escape speed allows an object moving...
View Answer

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E

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