Astronomy chapter 13 and 14 questions

Two spaceships are moving in opposite directions: spaceship A traveling at 0.9c and spaceship B traveling at 0.95c. Which of the following statements is true? B measures A moving at the speed of light. A measures B moving at the speed of light. Both measure light passing them at c. Only A is actually moving. Only B is actually moving.

Both measure light passing them at c.

An observer moving at 90 percent of the speed of light (0.9c) would observe light around him to be moving at 0.9c. 0.1c. c. 0.81c. -0.1c.

C.

According to the general theory of relativity, a satellite orbits Earth because: Earth has deformed space around it, so the satellite is trapped in a circular well. Earth has deformed space-time in such a way that the satellite falls freely through it. the spinning Earth's frame of reference drags the satellite with it. Earth has deformed space around it, so the satellite's frame of reference rotates.

Earth has deformed space-time in such a way that the satellite falls freely through it.

Which of the following statements about the sequential nuclear fusion that occurs in a high-mass star is true? The duration of fusion increases as increasingly heavy elements are produced. Lighter end products are created in each successive stage. The last element that serves as input to nuclear fusion is iron. Higher temperatures are required for nuclear fusion of each successively heavier element. Fusion can occur in only one shell at a time.

Higher temperatures are required for nuclear fusion of each successively heavier element.

Why does stellar fusion end with an iron core? The core becomes so hot it expands too much. Iron cannot undergo fusion. Iron does not produce energy when it undergoes fusion. Iron requires such a high temperature for fusion that it does not occur inside stars.

Iron does not produce energy when it undergoes fusion.

Which statement accurately describes a neutron star? It is an object created from the outer layers of a high-mass star. It is a star fusing iron in its core. It is an object that results from the death of a massive star. It is an object created by electron degeneracy pressure. It is the end product of a very-low-mass star.

It is an object that results from the death of a massive star.

Why is the Schwarzschild radius significant? It is the distance within which space-time breaks down. It is the distance within which nothing can escape a black hole. It is the distance within which gravitational lensing is strong. It is the distance within which the black hole's tidal forces are strong.

It is the distance within which nothing can escape a black hole.

Which of the following statements about Einstein's theory of gravity, compared with Newton's law of gravity, is true? It concluded that the effect of mass is less than expected, while that of distance is more than expected. It concluded that the effect of distance is less than expected, while that of mass is more than expected. It proved Newton's law entirely wrong. It made the use of Newton's law unnecessary. It showed that Newton's laws were a "limiting case" of general relativity that applied only when the curvature of space-time was not dramatic

It showed that Newton's laws were a "limiting case" of general relativity that applied only when the curvature of space-time was not dramatic

How do the laws of physics change for moving observers? Kinetic energies are always larger for moving observers. The Doppler effect is stronger for moving observers. Gravity is weaker for moving observers. None of the laws change.

None of the laws change.

What does the Heisenberg uncertainty principle imply about the behavior of an electron? The more confined it is, the greater will be the range of its velocity. When its velocity is greater, it requires more space. The greater the uncertainty in its position, the higher will be the range of its velocity. The electron can be squeezed out when matter becomes degenerate. The charge of the electron is reduced when it is confined.

The more confined it is, the greater will be the range of its velocity.

Which of the following statements about white dwarfs is true? They can be the remains of massive stars. They don't allow any light to escape. They first appear at the center of a planetary nebula. They are smaller than neutron stars. The larger their mass, the larger their radius.

They first appear at the center of a planetary nebula.

If GPS satellites orbited higher, which of the following would be true regarding the general relativistic adjustments currently required for accurate positioning over Earth's surface? They would be greater because of the difference in the satellites' speed. They would be smaller because of the difference in the satellites' speed. They would be the same since the surface positions remain the same. They would be greater because of the greater difference in the curvature of space-time between the ground and satellite. They would be the same because general relativity can be ignored in the near-Earth environment.

They would be greater because of the greater difference in the curvature of space-time between the ground and satellite.

What do astronomers believe exists in the center of nearly every galaxy? a gamma-ray burst a massive dust cloud a star-forming region a black hole

a black hole

A pulsar is also a neutron star. a white dwarf. a strong source of visible light. a dead low-mass star. the site of a nova.

a neutron star.

Which of the following shares your reference frame while you're reading this book in your room? an astronaut on the Moon a geosynchronous satellite directly over your location an airplane 30,000 feet up in the atmosphere traveling 400 miles per hour an Indy driver speeding on the course a person sitting in an adjacent room of your dwelling

a person sitting in an adjacent room of your dwelling

Which of the following is closest in radius to a neutron star? Earth the United States a small city a football stadium

a small city

Einstein showed that Newton's physics is: wrong. accurate only at low masses. accurate only at large distances. accurate only at low velocities.

accurate only at low velocities.

Essentially all the elements heavier than iron in our Milky Way were formed by supernovae. by fusion in the cores of the most massive main-sequence stars. during the formation of planetary nebulae. during the initial stages of the Big Bang.

by supernovae.

A star is determined to be burning helium into carbon in a shell above its core. What mass star can it be? only low-mass only intermediate-mass only high-mass either intermediate-mass or massive any size

either intermediate-mass or massive

The general theory of relativity includes an explanation of: the four fundamental forces. gravity and space-time. quantum mechanics and gravity. light waves and photons.

gravity and space-time.

A star is on the horizontal branch of the HR diagram. Which of the following describes nuclear fusion within the star? only hydrogen to helium in the core helium to carbon in the core; none in shells above the core no fusion in the core; hydrogen to helium in the first shell helium to carbon in the core; hydrogen to helium in the first shell no fusion in the core; helium to carbon in the first shell; hydrogen to helium in the second shell

helium to carbon in the core; hydrogen to helium in the first shell

Which of the following accurately describes changes to a star when it first moves off the main sequence of the HR diagram? increased radius and increased surface temperature increased radius and decreased surface temperature shorter wavelength of peak radiation decreased luminosity absence of nuclear fusion

increased radius and decreased surface temperature

As an object approaches the event horizon of a black hole, the light from it is observed to become longer in wavelength. shorter in wavelength. slower and slower. faster and faster. unchanged.

longer in wavelength.

The Sun will undergo fusion in its core during which of the following evolutionary phases? main sequence and horizontal branch main sequence and red giant main sequence only main sequence, red giant, horizontal branch, and asymptotic giant branch

main sequence and horizontal branch

An isolated star's eventual fate is ultimately determined by its: environment. composition. mass. distance.

mass

Which of the following has the highest density? intermediate-mass main-sequence star white dwarf neutron star planetary nebula high-mass main-sequence star

neutron star

What stops the collapse of the most massive stars at the end of their lives? nothing electron degeneracy pressure neutron degeneracy pressure gamma-ray bursts

nothing

A star is 10 billion years old. What final form may it take when it dies? white dwarf or black hole, but not neutron star neutron star or black hole, but not white dwarf only a white dwarf only a black hole There's not enough information to answer the question.

only a white dwarf

A patent clerk in a spaceship observes that time on the clock of an astronaut on a spaceship passing at 0.25c runs slower than does time on his own clock. This phenomenon is called relativistic time dilation. time travel. gravitational time dilation. curvature of space-time. time warp.

relativistic time dilation.

What kind of stars are most likely to form black holes? stars that can only initiate hydrogen and helium fusion stars with low-mass cores stars with masses greater than 30 MSun stars with an overabundance of heavy elements

stars with masses greater than 30 MSun

As a star moves along the red giant branch, how does it move on the HR diagram? It does not move. downward and to the left upward and to the left upward and to the right

upward and to the right

The Sun will end its life as a: neutron star. white dwarf. black hole. red giant.

white dwarf.