Question 1

According to Newton's law of gravity,why does Earth orbit the Sun?

Accepted Answer

A)   The Sun exerts a gravitational force on Earth across empty space.
B)   Earth and the Sun are continually exchanging photons of light in a way that holds Earth in orbit.
C)   Matter contains quarks, and Earth and the Sun attract each other with the "color force" between their quarks.
D)   Space around the Sun is curved.E) A) and D)
F) None of the above

Question 2

Which process is NOT involved in the supernova explosion of a massive star?

Accepted Answer

A)   the photodisintegration of nuclei by gamma rays
B)   the helium flash in the star's core
C)   the collapse of the star's core
D)   the passage of a shock wave through the star's envelopeE) A) and C)
F) A) and D)

Question 3

Which statement is NOT an observation confirming the predictions of general relativity?

Accepted Answer

A)   Light is deflected in the curved space near the Sun.
B)   The perihelion of the orbit of Mercury shifts more than the amount predicted by Newtonian physics.
C)   Primordial black holes have been detected.
D)   The spectra of stars exhibit the gravitational redshift.E) None of the above
F) A) and B)

Question 4

What happens to the density of an object as it moves with respect to you as compared with the same object at rest with respect to you?

Accepted Answer

A)   The density will decrease.
B)   The density will remain unchanged.
C)   The density will increase.
D)   The density can either increase or decrease depending on its direction of motion with respect to you.E) A) and C)
F) All of the above

Question 5

Consider a group of stars with masses up to eight times the mass of the Sun.Stars of which masses will pass along the asymptotic giant branch?

Accepted Answer

A)   less than 0.4 M
B)   0.4 M to 2 M only
C)   2 M to 8 M only
D)   all stars 0.4 M to 8 ME) A) and C)
F) B) and C)

Question 6

Suppose a satellite were placed in orbit around (and very close to) a neutron star.Which theory would you need to use to describe how it moves?

Accepted Answer

A)   the special theory of relativity
B)   the general theory of relativity
C)   Kepler's laws
D)   Newton's law of gravitationE) A) and B)
F) B) and C)

Question 7

In what manner does an isolated white dwarf generate energy?

Accepted Answer

A)   hydrogen fusion
B)   helium fusion
C)   gravitational contraction
D)   An isolated white dwarf does not generate energy.E) None of the above
F) A) and D)

Question 8

In a nova,the radiation outburst is caused by fusion of hydrogen to produce helium on the surface of a white dwarf.The radiation outburst from an X-ray burster is caused by fusion of:

Accepted Answer

A)   hydrogen to produce helium on the surface of a neutron star.
B)   hydrogen to produce helium in the interior of a neutron star.
C)   helium to produce carbon on the surface of a neutron star.
D)   carbon to produce oxygen in the interior of a neutron star.E) B) and C)
F) C) and D)

Question 9

The outermost layer of a neutron star is believed to consist of:

Accepted Answer

A)   a dense gas consisting mostly of neutrons.
B)   a molten ocean of heavy elements such as iron, neon, and magnesium.
C)   a solid crust.
D)   superfluid neutrons.E) A) and C)
F) A) and B)

Question 10

A massive blue-white supergiant star emits the Hα wavelength from its surface,as does a much less massive red dwarf.Will these wavelengths differ when you see them? If so,how?

Accepted Answer

A)   The light from the more massive star will have the shorter wavelength.
B)   The light from the less massive star will have the shorter wavelength.
C)   Both wavelengths will appear the same, and this will also match the wavelength of an Hα source here on Earth.
D)   Both wavelengths will appear the same, but both will be longer than the wavelength from an Hα source here on Earth.E) B) and C)
F) A) and C)

Question 11

A planetary nebula is created:

Accepted Answer

A)   over several hundred years, during mass transfer in a close binary star system.
B)   over a few thousand years or more, in a slow expansion away from a low-mass star, driven by a series of thermal pulses from helium fusion.
C)   in hours or less, during the explosion of a massive star.
D)   in seconds, during the helium flash in a low-mass star.E) B) and C)
F) A) and B)

Question 12

The one characteristic shared by all solitary white dwarfs is that they:

Accepted Answer

A)   have stopped generating thermonuclear energy but continue to shrink, thereby releasing gravitational energy as heat.
B)   have never generated either thermonuclear or gravitational energy but are slowly cooling after their production in a supernova explosion.
C)   are generating thermonuclear energy but are maintaining a constant radius and hence are not releasing gravitational energy.
D)   have ceased to generate energy by thermonuclear processes or gravitational contraction and are slowly cooling down.E) B) and D)
F) B) and C)

Question 13

The solar mass of the star that exploded to form supernova SN 1987A was probably about:

Accepted Answer

A)   1.4.
B)   40.
C)   less than 1.
D)   20.E) A) and B)
F) None of the above

Question 14

Gamma-ray bursters are great distances from Earth,yet Earth receives tremendous amounts of energy from them.Explain.

Accepted Answer

A)   Gamma-ray bursters are supermassive stars, equivalent to 100,000 ordinary supernovae.
B)   A gamma-ray burster represents the explosion of an entire galaxy.
C)   The energy is released along jets rather than uniformly in all directions. If Earth is in the path of one of these jets, we see a gamma-ray burster.
D)   The gamma radiation from a burster is released in all directions, but then it is focused in the direction of Earth by gravitational lensing.E) A) and D)
F) A) and C)

Question 15

A pulsar is a(n) :

Accepted Answer

A)   rapidly spinning neutron star.
B)   type of variable star, pulsating rapidly in size and brightness.
C)   very precise interstellar beacon perhaps operated by intelligent life forms.
D)   accretion disk around a black hole, emitting light as matter is accumulated on the disk.E) A) and D)
F) B) and C)

Question 16

The two longest stages in the lifetime of a solar-mass star,each lasting billions of years,are:

Accepted Answer

A)   protostar and main sequence.
B)   main sequence and red giant.
C)   red giant and white dwarf.
D)   main sequence and white dwarf.E) None of the above
F) A) and B)

Question 17

Particle degeneracies stemming from the Pauli exclusion principle support stars of various masses.Which particles have we discussed in this context?

Accepted Answer

A)   electrons and neutrons
B)   electrons and protons
C)   protons and neutrons
D)   hydrogen atoms and electronsE) B) and C)
F) A) and B)

Question 18

In this chapter,we consider high-mass stars.What is considered to be the lower mass limit for a high-mass star?

Accepted Answer

A)   0.4 M
B)   2 M
C)   8 M
D)   25 ME) A) and D)
F) All of the above

Question 19

Which statement BEST describes the "fabric" of space and time as outlined by the classical physics of Newton?

Accepted Answer

A)   Space is expanding uniformly, while time passes more slowly as the universe ages.
B)   Space becomes "curved" and time slows down near a source of gravity, as measured by a distant observer.
C)   The shape of space and the rate of passage of time depend on the relative velocities of observer and observed.
D)   Space is perfectly uniform, filling everywhere like a fixed network, while time passes at a uniform rate for all observers.E) A) and D)
F) B) and D)

Question 20

What is a cosmic ray shower?

Accepted Answer

A)   a shower of particles produced when a cosmic ray strikes atoms in Earth's atmosphere
B)   a burst of high-energy atomic nuclei arriving at Earth from interstellar space
C)   another name for a meteor shower
D)   a pulse of gamma rays arriving at Earth from a rotating, magnetized neutron starE) None of the above
F) All of the above

Exam 12: The Deaths and Remnants of Stars

What happens to the density of an object as it moves with respect to you as compared with the same object at rest with respect to you?

Correct AnswerverifiedShow Answer

Particle degeneracies stemming from the Pauli exclusion principle support stars of various masses.Which particles have we discussed in this context?

Correct AnswerverifiedShow Answer

In this chapter,we consider high-mass stars.What is considered to be the lower mass limit for a high-mass star?

Correct AnswerverifiedShow Answer

The outermost layer of a neutron star is believed to consist of:

Correct AnswerverifiedShow Answer

In what manner does an isolated white dwarf generate energy?

Correct AnswerverifiedShow Answer

Consider a group of stars with masses up to eight times the mass of the Sun.Stars of which masses will pass along the asymptotic giant branch?

Correct AnswerverifiedShow Answer

Gamma-ray bursters are great distances from Earth,yet Earth receives tremendous amounts of energy from them.Explain.

Correct AnswerverifiedShow Answer

A pulsar is a(n) :

Correct AnswerverifiedShow Answer

In a nova,the radiation outburst is caused by fusion of hydrogen to produce helium on the surface of a white dwarf.The radiation outburst from an X-ray burster is caused by fusion of:

Correct AnswerverifiedShow Answer

Which process is NOT involved in the supernova explosion of a massive star?

Correct AnswerverifiedShow Answer

The solar mass of the star that exploded to form supernova SN 1987A was probably about:

Correct AnswerverifiedShow Answer

According to Newton's law of gravity,why does Earth orbit the Sun?

Correct AnswerverifiedShow Answer

What is a cosmic ray shower?

Correct AnswerverifiedShow Answer

The one characteristic shared by all solitary white dwarfs is that they:

Correct AnswerverifiedShow Answer

The two longest stages in the lifetime of a solar-mass star,each lasting billions of years,are:

Correct AnswerverifiedShow Answer

A massive blue-white supergiant star emits the Hα wavelength from its surface,as does a much less massive red dwarf.Will these wavelengths differ when you see them? If so,how?

Correct AnswerverifiedShow Answer

Suppose a satellite were placed in orbit around (and very close to) a neutron star.Which theory would you need to use to describe how it moves?

Correct AnswerverifiedShow Answer

Which statement BEST describes the "fabric" of space and time as outlined by the classical physics of Newton?

Correct AnswerverifiedShow Answer

A planetary nebula is created:

Correct AnswerverifiedShow Answer

Which statement is NOT an observation confirming the predictions of general relativity?

Correct AnswerverifiedShow Answer

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