Question 1

The escape velocity of an object depends on
I. the mass of that object.
II. the mass of the object trying to escape.
III. the distance from the center of the object and the escaping object.
IV. the speed of light.

Accepted Answer

A)   I, II, III, IV
B)   I II
C)   I,III
D)   I, II, IV
E)   I, III, IVF) C) and D)
G) A) and B)

Question 2

A(n)  ____ is a collection of 100 to 1000 stars in a region about 25 pc in diameter. The stars in the collection are typically quite young.

Accepted Answer

A)   Herbig Haro object
B)   globular cluster
C)   open cluster
D)   giant cluster
E)   supernovaF) B) and C)
G) B) and D)

Question 3

Star clusters are important to our study of stars because

Accepted Answer

A)   all stars formed in star clusters.
B)   the sun was once a member of a globular cluster.
C)   they give us a method to test the our theories and models of stellar evolution.
D)   they are the only objects that contain Cepheid variables.
E)   all of the aboveF) D) and E)
G) A) and E)

Question 4

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

Accepted Answer

A)   smaller than the speed of light.
B)   equal to the speed of light.
C)   much larger than the speed of light.
D)   irrelevant since nothing (including light)  can escape from a black hole.E) B) and C)
F) C) and D)

Question 5

Why can t lower main sequence stars become giant stars?

Accepted Answer

The answer of Why can t lower main sequence stars...

Question 6

Helium fusion does not begin until the star has entered the giant region of the H-R diagram.

Accepted Answer

A) True 
 B)False

Question 7

The triple alpha process

Accepted Answer

A)   controls the pulsations in Cepheid variable stars.
B)   is the nuclear fusion of hydrogen to helium in massive stars.
C)   is the process that produces the neutrinos we receive from the sun.
D)   requires a temperature of about 5,000,000 K to operate
E)   occurs during helium flash.F) D) and E)
G) A) and C)

Question 8

Planetary nebulae are sites of planet formation.

Accepted Answer

A) True 
 B)False

Question 9

A star begins fusing hydrogen to helium the moment it leaves the main sequence.

Accepted Answer

A) True 
 B)False

Question 10

As a white dwarf cools its radius will not change because

Accepted Answer

A)   pressure due to nuclear reactions in a shell just below the surface keeps it from collapsing.
B)   pressure does not depend on temperature for a white dwarf because the electrons are degenerate.
C)   pressure does not depend on temperature because the white dwarf is too hot.
D)   pressure does not depend on temperature because the star has exhausted all its nuclear fuels.
E)   material accreting onto it from a companion maintains a constant radius.F) A) and D)
G) A) and C)

Question 11

Because more massive stars have more gravitational energy, they can fuse heavier nuclear fuels.

Accepted Answer

A) True 
 B)False

Question 12

The density of a ___________ is greater than the density of a ___________.

Accepted Answer

A)   white dwarf, neutron star
B)   neutron star, black hole
C)   pulsar, neutron star
D)   pulsar, white dwarf
E)   white dwarf, black holeF) B) and D)
G) C) and E)

Question 13

When material expanding away from a star in a binary system reaches the Roche surface

Accepted Answer

A)   the material will start to fall back toward the star.
B)   all of the material will accrete on to the companion.
C)   the material is no longer gravitationally bound to the star.
D)   the material will increase in temperature an eventually undergo thermonuclear fusion.
E)   c and dF) C) and E)
G) B) and D)

Question 14

The Chandrasekhar limit tells us that

Accepted Answer

A)   accretion disks can grow hot through friction.
B)   neutron stars of more than 3 solar masses are not stable.
C)   white dwarfs more massive than 1.4 solar masses are not stable.
D)   stars cannot travel through space too fast
E)   stars with a mass less than 0.5 solar masses will not go through helium flash.F) A) and E)
G) A) and B)

Question 15

Giant and supergiant stars are rare because

Accepted Answer

A)   they do not form as often as main sequence stars.
B)   the star blows up before the giant or supergiant stage is reached
C)   the giant or supergiant stage is very short.
D)   the giant or supergaint stage is very longE) A) and B)
F) A) and C)

Question 16

A pulsar requires that a neutron star
I. rotate rapidly.
II. have a radius of at least 10 km.
III. have a strong magnetic field.
IV. rotate on an axis that is different from the axis of the magnetic field.

Accepted Answer

A)   I,III
B)   I, IV
C)   II, III, IV
D)   I, III, IV
E)   I, II, III, IVF) A) and B)
G) B) and E)

Question 17

Cygnus X-1 and LMC X-3 are black holes if the masses of the unseen companions are

Accepted Answer

A)   less than 5 solar masses.
B)   more than 5 solar masses.
C)   between 0.4 and 1.4 solar masses.
D)   less than 0.4 solar masses
E)   not larger than the masses of the stars that we can see.F) All of the above
G) B) and E)

Question 18

The theory that the collapse of a massive star s iron core produces neutrinos was supported by

Accepted Answer

A)   the size and structure of the Crab nebula.
B)   laboratory measurements of the mass of the neutrino.
C)   the brightening of supernovae a few days after they are first visible
D)   underground counts from solar neutrinos.
E)   the detection of neutrinos from the supernova of 1987.F) B) and D)
G) A) and E)

Question 19

A(n) ____________________ is a rapidly spinning neutron star that accelerates charged particles near the poles of its magnetic field.

Accepted Answer

The answer of A(n) ____________________ is a rapidly spinning neutron...

Question 20

The Algol paradox is explained by considering

Accepted Answer

A)   the degenerate nature of the hydrogen on the surface of the white dwarf.
B)   synchrotron radiation
C)   the rate of expansion of the shock wave inside the supernova.
D)   the rotation rate of a neutron star.
E)   mass transfer between the two stars in a binary system.F) A) and B)
G) A) and D)

Exam 11: The Deaths of Stars

Why can t lower main sequence stars become giant stars?

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Because more massive stars have more gravitational energy, they can fuse heavier nuclear fuels.

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The density of a ___________ is greater than the density of a ___________.

Correct AnswerverifiedShow Answer

Giant and supergiant stars are rare because

Correct AnswerverifiedShow Answer

Helium fusion does not begin until the star has entered the giant region of the H-R diagram.

Correct AnswerverifiedShow Answer

The escape velocity of an object depends on I. the mass of that object. II. the mass of the object trying to escape. III. the distance from the center of the object and the escaping object. IV. the speed of light.

Correct AnswerverifiedShow Answer

The theory that the collapse of a massive star s iron core produces neutrinos was supported by

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Star clusters are important to our study of stars because

Correct AnswerverifiedShow Answer

Cygnus X-1 and LMC X-3 are black holes if the masses of the unseen companions are

Correct AnswerverifiedShow Answer

When material expanding away from a star in a binary system reaches the Roche surface

Correct AnswerverifiedShow Answer

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

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A(n) ____________________ is a rapidly spinning neutron star that accelerates charged particles near the poles of its magnetic field.

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As a white dwarf cools its radius will not change because

Correct AnswerverifiedShow Answer

The Algol paradox is explained by considering

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Planetary nebulae are sites of planet formation.

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A star begins fusing hydrogen to helium the moment it leaves the main sequence.

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The Chandrasekhar limit tells us that

Correct AnswerverifiedShow Answer

A pulsar requires that a neutron star I. rotate rapidly. II. have a radius of at least 10 km. III. have a strong magnetic field. IV. rotate on an axis that is different from the axis of the magnetic field.

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The triple alpha process

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A(n) ____ is a collection of 100 to 1000 stars in a region about 25 pc in diameter. The stars in the collection are typically quite young.

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