Question 1

Which object can be a pulsar

Accepted Answer

A) white dwarf 
B) neutron star 
C) black hole 
D) None of the other choices are correct. 
A) white dwarf 
B) neutron star 
C) black hole 
D) None of the other choices are correct. B

Question 2

Pulsars could not be ordinary stars that are pulsating because the pulses are too short.

Accepted Answer

A) True 
 B)False  True

Question 3

Neutron stars have densities roughly the same as that of the atomic nucleus.

Accepted Answer

A) True 
 B)False  True

Question 4

For a point mass equal to that of the Sun, how far does the Schwarzschild radius extend from its center

Accepted Answer

A) A few kilometers away 
B) A few solar radii away 
C) A few astronomical units (AU) away 
D) A few parsecs away 
A) A few kilometers away 
B) A few solar radii away 
C) A few astronomical units (AU) away 
D) A few parsecs away

Question 5

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 6

Similar to our Sun, pulsars' rotations are believed to slow down because

Accepted Answer

A) they are losing angular momentum into space via outward streaming particles. 
B) they are dragging companion stars around in their magnetic field. 
C) they are getting tired. 
D) of conservation of angular momentum. 
E) their mass is increasing. 
A) they are losing angular momentum into space via outward streaming particles. 
B) they are dragging companion stars around in their magnetic field. 
C) they are getting tired. 
D) of conservation of angular momentum. 
E) their mass is increasing.

Question 7

The Crab pulsar emits light in which wavelength bands

Accepted Answer

A) visual 
B) gamma 
C) X-ray 
D) All of the other choices are correct. 
A) visual 
B) gamma 
C) X-ray 
D) All of the other choices are correct.

Question 8

Why might we suspect that a black hole in a binary system could emit X-rays

Accepted Answer

If matter flows into a black h

Question 9

Fraud in science is rare because it is difficult to commit. Why is it difficult to commit fraud in science

Accepted Answer

A) Science requires that experimental and theoretical findings be reproducible. 
B) All scientists are bound by a code of ethics preventing them from publishing fraudulent work. 
C) Scientific results are reviewed by other scientists before they are published. 
D) Scientific journals only allow certain highly trusted individuals to publish their work. 
E) Science requires that experimental and theoretical findings be reproducible and scientific results are reviewed by other scientists before they are published. 
A) Science requires that experimental and theoretical findings be reproducible. 
B) All scientists are bound by a code of ethics preventing them from publishing fraudulent work. 
C) Scientific results are reviewed by other scientists before they are published. 
D) Scientific journals only allow certain highly trusted individuals to publish their work. 
E) Science requires that experimental and theoretical findings be reproducible and scientific results are reviewed by other scientists before they are published.

Question 10

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. 
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.

Question 11

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, & IV 
A) I & III 
B) I & IV 
C) II, III, & IV 
D) I, III, & IV 
E) I, II, III, & IV

Question 12

The object left behind after the 1054 AD supernova explosion has been observed at the center of the Crab nebula. The object is a

Accepted Answer

A) white dwarf. 
B) neutron star. 
C) red giant. 
D) protostar. 
A) white dwarf. 
B) neutron star. 
C) red giant. 
D) protostar.

Question 13

Neutron stars are expected to spin rapidly because

Accepted Answer

A) they conserved angular momentum when they collapsed. 
B) they have high orbital velocities. 
C) they have high densities. 
D) they have high temperatures. 
E) the energy from the supernova explosion that formed them made them spin faster. 
A) they conserved angular momentum when they collapsed. 
B) they have high orbital velocities. 
C) they have high densities. 
D) they have high temperatures. 
E) the energy from the supernova explosion that formed them made them spin faster.

Question 14

What evidence do we have that pulsars are neutron stars

Accepted Answer

Pulsars could not be ordinary stars. A n

Question 15

Although neutron stars are very hot, they are faint and not easy to see at visual wavelengths because

Accepted Answer

A) light does not escape from their event horizon. 
B) most lie beyond dense dust clouds. 
C) they have only a small surface area from which to emit. 
D) the peak of their thermal emission is at much shorter wavelengths than visual. 
E) they have only a small surface area from which to emit and the peak of their thermal emission is at much shorter wavelengths than visual. 
A) light does not escape from their event horizon. 
B) most lie beyond dense dust clouds. 
C) they have only a small surface area from which to emit. 
D) the peak of their thermal emission is at much shorter wavelengths than visual. 
E) they have only a small surface area from which to emit and the peak of their thermal emission is at much shorter wavelengths than visual.

Question 16

The event horizon marks the boundary within which the density is roughly the same as that of the atomic nucleus.

Accepted Answer

A) True 
 B)False

Question 17

An isolated black hole in empty intergalactic space would be difficult to detect because

Accepted Answer

A) there would be no stars behind it whose light would be affected by gravitational lensing. 
B) it could not emit light from inside its event horizon. 
C) no companion stars would be affected by its gravitational field. 
D) no matter would be falling into it to create an X-ray-emitting accretion disk. 
E) All of the other choices are correct. 
A) there would be no stars behind it whose light would be affected by gravitational lensing. 
B) it could not emit light from inside its event horizon. 
C) no companion stars would be affected by its gravitational field. 
D) no matter would be falling into it to create an X-ray-emitting accretion disk. 
E) All of the other choices are correct.

Question 18

The ___________ of a black hole is the radius from a black hole at which the escape velocity is approximately equal to the speed of light.

Accepted Answer

A) Roche limit 
B) Lagrangian point 
C) Chandraskhar limit 
D) Hubble radius 
E) event horizon 
A) Roche limit 
B) Lagrangian point 
C) Chandraskhar limit 
D) Hubble radius 
E) event horizon

Question 19

Millisecond pulsars that are very old are

Accepted Answer

A) believed to be the result of mass transfer from a companion that increased the spin of the pulsar. 
B) all single objects. 
C) not spinning as rapidly as they seem because they have four hot spots that produce the flashes. 
D) X-ray binaries. 
E) gamma-ray bursters. 
A) believed to be the result of mass transfer from a companion that increased the spin of the pulsar. 
B) all single objects. 
C) not spinning as rapidly as they seem because they have four hot spots that produce the flashes. 
D) X-ray binaries. 
E) gamma-ray bursters.

Question 20

in the following graph of a pulsar in a binary, the motion of the pulsar from 2.75 hours to 3.5 hours is ___________________.

Accepted Answer

A) moving away from Earth 
B) moving towards Earth 
C) in motion perpendicular to the line-of-sight 
D) in motion perpendicular to the line-of-sight followed by motion towards Earth 
A) moving away from Earth 
B) moving towards Earth 
C) in motion perpendicular to the line-of-sight 
D) in motion perpendicular to the line-of-sight followed by motion towards Earth

Which object can be a pulsar

Pulsars could not be ordinary stars that are pulsating because the pulses are too short.

Neutron stars have densities roughly the same as that of the atomic nucleus.

For a point mass equal to that of the Sun, how far does the Schwarzschild radius extend from its center

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

Similar to our Sun, pulsars' rotations are believed to slow down because

The Crab pulsar emits light in which wavelength bands

Why might we suspect that a black hole in a binary system could emit X-rays

Fraud in science is rare because it is difficult to commit. Why is it difficult to commit fraud in science

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

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.

The object left behind after the 1054 AD supernova explosion has been observed at the center of the Crab nebula. The object is a

Neutron stars are expected to spin rapidly because

What evidence do we have that pulsars are neutron stars

Although neutron stars are very hot, they are faint and not easy to see at visual wavelengths because

The event horizon marks the boundary within which the density is roughly the same as that of the atomic nucleus.

An isolated black hole in empty intergalactic space would be difficult to detect because

The ___________ of a black hole is the radius from a black hole at which the escape velocity is approximately equal to the speed of light.

Millisecond pulsars that are very old are

in the following graph of a pulsar in a binary, the motion of the pulsar from 2.75 hours to 3.5 hours is ___________________.

Here and Now

A Users Guide to the Sky

Cycles of the Sun and Moon

The Origin of Modern Astronomy

Light and Telescopes

Atoms and Spectra

The Sun

The Family of Stars

The Formation and Structure of Stars

The Deaths of Stars

The Milky Way Galaxy

Galaxies: Normal and Active

Modern Cosmology

The Origin of the Solar System

Earth and Moon: Bases for Comparative Planetology

Mercury, Venus, and Mars

The Outer Solar System

Meteorites, Asteroids, and Comets

Astrobiology: Life on Other Worlds

Filters

Exam 11: Neutron Stars and Black Holes

Which object can be a pulsar

Pulsars could not be ordinary stars that are pulsating because the pulses are too short.

Neutron stars have densities roughly the same as that of the atomic nucleus.

For a point mass equal to that of the Sun, how far does the Schwarzschild radius extend from its center

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

Similar to our Sun, pulsars' rotations are believed to slow down because

The Crab pulsar emits light in which wavelength bands

Why might we suspect that a black hole in a binary system could emit X-rays

Fraud in science is rare because it is difficult to commit. Why is it difficult to commit fraud in science

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

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.

The object left behind after the 1054 AD supernova explosion has been observed at the center of the Crab nebula. The object is a

Neutron stars are expected to spin rapidly because

What evidence do we have that pulsars are neutron stars

Although neutron stars are very hot, they are faint and not easy to see at visual wavelengths because

The event horizon marks the boundary within which the density is roughly the same as that of the atomic nucleus.

An isolated black hole in empty intergalactic space would be difficult to detect because

The ___________ of a black hole is the radius from a black hole at which the escape velocity is approximately equal to the speed of light.

Millisecond pulsars that are very old are

in the following graph of a pulsar in a binary, the motion of the pulsar from 2.75 hours to 3.5 hours is ___________________.

Here and Now

A Users Guide to the Sky

Cycles of the Sun and Moon

The Origin of Modern Astronomy

Light and Telescopes

Atoms and Spectra

The Sun

The Family of Stars

The Formation and Structure of Stars

The Deaths of Stars

The Milky Way Galaxy

Galaxies: Normal and Active

Modern Cosmology

The Origin of the Solar System

Earth and Moon: Bases for Comparative Planetology

Mercury, Venus, and Mars

The Outer Solar System

Meteorites, Asteroids, and Comets

Astrobiology: Life on Other Worlds

Filters