Question 1

How does the diameter of a black hole (size of the event horizon) depend on the mass inside the black hole?

Accepted Answer

A)   The greater the mass,the smaller the diameter.
B)   The greater the mass,the greater the diameter up to the mass limit for a black hole;above that mass,the black hole collapses.
C)   The diameter does not depend on the mass.
D)   The greater the mass,the greater the diameter.E) A) and B)
F) None of the above

Question 2

What is the event horizon in relationship to black holes?

Accepted Answer

It is the "surface" around a b...

Question 3

The diameter of the black hole candidate Cygnus X-1 has been estimated by

Accepted Answer

A)   combining the amount of energy received at Earth per second with the distance to the source to estimate the total energy emitted per second.
B)   measuring how quickly it flickers in intensity.
C)   measuring how long it takes to block off the light from its companion star during an eclipse (i.e. ,as it passes in front of its companion star as seen from Earth) .
D)   combining its distance with its angular diameter to find its physical size.E) All of the above
F) A) and B)

Question 4

A neutron star is a stellar corpse supported by

Accepted Answer

A)   electron degeneracy pressure.
B)   neutron degeneracy pressure.
C)   black hole pressure.
D)   None of theseE) All of the above
F) B) and C)

Question 5

In a binary star system,an unseen component is found to have a mass of about 8 solar masses.If this were a normal star,then it would be visible,so it must be a collapsed object.Theoretical considerations tell us that it must be a

Accepted Answer

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

Question 6

A neutron star will be detected from Earth as a pulsar by its regular radio pulses ONLY if Earth lies

Accepted Answer

A)   in the plane of the neutron star's magnetic equator,halfway between its magnetic poles.
B)   almost directly in line with the magnetic axis of the neutron star at some time during the star's rotation.
C)   directly above the rotation axis of the rotating neutron star.
D)   in the neutron star's "equator," the plane perpendicular to its spin axis.E) None of the above
F) A) and D)

Question 7

In general,a Type Ia supernova is brighter than a Type II supernova.

Accepted Answer

A) True 
 B)False

Question 8

What is actually located at the event horizon of a black hole,to define this entity?

Accepted Answer

A)   An infinitely dense concentration of mass
B)   A magnetic field of immense strength
C)   A sphere of photons
D)   NothingE) None of the above
F) C) and D)

Question 9

When a star becomes a black hole,its gravitational pull becomes stronger.

Accepted Answer

A) True 
 B)False

Question 10

What is the difference between a stellar black hole and a supermassive black hole?

Accepted Answer

A stellar black hole is produced by the ...

Question 11

At what location in the space around a black hole does the escape velocity become equal to the speed of light?

Accepted Answer

A)   At the point where escaping X-rays are produced
B)   At the point where clocks are observed to slow down by a factor of 2
C)   At the event horizon
D)   At the singularityE) A) and D)
F) A) and C)

Question 12

A pulsar is a(n)

Accepted Answer

A)   interstellar beacon manufactured by little green persons (LGPs) .
B)   type of variable star,pulsating rapidly in size and brightness.
C)   rapidly spinning neutron star.
D)   accretion disk around a black hole,emitting light as matter is accumulated on the disk.E) A) and D)
F) All of the above

Question 13

All black holes have the same amount of gravitational force.

Accepted Answer

A) True 
 B)False

Question 14

Every year,two or three supernovae are seen within our own Galaxy.

Accepted Answer

A) True 
 B)False

Question 15

X-rays that come from the vicinity of a black hole actually originate from

Accepted Answer

A)   well inside the event horizon.
B)   its exact center,or singularity.
C)   relatively far away from the black hole,where matter is still relatively cool.
D)   just outside the event horizon,on the accretion disk.E) All of the above
F) B) and D)

Question 16

If,by definition,no light can escape from a black hole,how are they detected?

Accepted Answer

They can be detected through the study o...

Question 17

Ancient Chinese astronomers recorded the appearance of what phenomenon in 1054 A.D.?

Accepted Answer

A)   A nearby nova explosion in a nearby galaxy
B)   A brilliant auroral display covering the whole Earth
C)   A supernova,visible in daylight,within our Galaxy
D)   A bright binary star undergoing eclipseE) A) and B)
F) C) and D)

Question 18

The term "Schwarzschild radius" refers to

Accepted Answer

A)   the distance to which gas is ejected in a planetary nebula.
B)   half the diameter of a neutron star.
C)   half the diameter of the singularity in a black hole.
D)   the distance from the center of a black hole at which the escape velocity becomes equal to the speed of light.E) B) and C)
F) C) and D)

Question 19

What is believed to be the mass of the black hole candidate Cygnus X-1?

Accepted Answer

A)   30 solar masses
B)   1 billion solar masses
C)   7 solar masses
D)   1 solar massE) B) and C)
F) A) and D)

Question 20

A Type Ia supernova is thought to result from the thermonuclear explosion of a white dwarf star in a close binary system with a larger companion star.

Accepted Answer

A) True 
 B)False

Exam 12: Predicting the Violent End of the Largest Stars

The diameter of the black hole candidate Cygnus X-1 has been estimated by

Correct AnswerverifiedShow Answer

At what location in the space around a black hole does the escape velocity become equal to the speed of light?

Correct AnswerverifiedShow Answer

In a binary star system,an unseen component is found to have a mass of about 8 solar masses.If this were a normal star,then it would be visible,so it must be a collapsed object.Theoretical considerations tell us that it must be a

Correct AnswerverifiedShow Answer

How does the diameter of a black hole (size of the event horizon) depend on the mass inside the black hole?

Correct AnswerverifiedShow Answer

What is believed to be the mass of the black hole candidate Cygnus X-1?

Correct AnswerverifiedShow Answer

A neutron star is a stellar corpse supported by

Correct AnswerverifiedShow Answer

X-rays that come from the vicinity of a black hole actually originate from

Correct AnswerverifiedShow Answer

Ancient Chinese astronomers recorded the appearance of what phenomenon in 1054 A.D.?

Correct AnswerverifiedShow Answer

The term "Schwarzschild radius" refers to

Correct AnswerverifiedShow Answer

A pulsar is a(n)

Correct AnswerverifiedShow Answer

When a star becomes a black hole,its gravitational pull becomes stronger.

Correct AnswerverifiedShow Answer

Every year,two or three supernovae are seen within our own Galaxy.

Correct AnswerverifiedShow Answer

A neutron star will be detected from Earth as a pulsar by its regular radio pulses ONLY if Earth lies

Correct AnswerverifiedShow Answer

A Type Ia supernova is thought to result from the thermonuclear explosion of a white dwarf star in a close binary system with a larger companion star.

Correct AnswerverifiedShow Answer

In general,a Type Ia supernova is brighter than a Type II supernova.

Correct AnswerverifiedShow Answer

All black holes have the same amount of gravitational force.

Correct AnswerverifiedShow Answer

What is actually located at the event horizon of a black hole,to define this entity?

Correct AnswerverifiedShow Answer

If,by definition,no light can escape from a black hole,how are they detected?

Correct AnswerverifiedThey can be detected through the study o...View AnswerShow Answer

What is the event horizon in relationship to black holes?

Correct AnswerverifiedIt is the "surface" around a b...View AnswerShow Answer

What is the difference between a stellar black hole and a supermassive black hole?

Correct AnswerverifiedA stellar black hole is produced by the ...View AnswerShow Answer

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They can be detected through the study o...
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It is the "surface" around a b...
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Correct Answer
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A stellar black hole is produced by the ...
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