Question 1

The Schwarzschild radius of a 2-   black hole is approximately

Accepted Answer

A)  6 km. 
B)  4 km. 
C)  2 km. 
D)  12 km. 
E)  36 km. 
A)  6 km. 
B)  4 km. 
C)  2 km. 
D)  12 km. 
E)  36 km. A

Question 2

The ____________________ theory describes pulsars as rotating neutron stars with strong magnetic fields that confine high-speed charged particles in two beams emanating from the magnetic poles of the neutron star.

Accepted Answer

lighthouse

Question 3

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. A

Question 4

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 companions 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 companions stars around in their magnetic field. 
C)  they are getting tired. 
D)  of conservation of angular momentum. 
E)  their mass is increasing.

Question 5

A black hole can be thought of as

Accepted Answer

A)  a very massive object of finite size. 
B)  a shell of material expanding from a white dwarf. 
C)  a massive body of infinitely small size. 
D)  a burnt out white dwarf. 
A)  a very massive object of finite size. 
B)  a shell of material expanding from a white dwarf. 
C)  a massive body of infinitely small size. 
D)  a burnt out white dwarf.

Question 6

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 7

At extremely high densities and temperatures, electrons can be forced to fuse with protons. This reaction produces

Accepted Answer

A)  hydrogen. 
B)  helium and energy. 
C)  degenerate electrons. 
D)  neutrons and neutrinos. 
E)  large amounts of radio radiation. 
A)  hydrogen. 
B)  helium and energy. 
C)  degenerate electrons. 
D)  neutrons and neutrinos. 
E)  large amounts of radio radiation.

Question 8

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 9

A(n) ____________________ periodically emits large amounts of X-ray radiation as material accretes around a neutron star or black hole.

Accepted Answer

The answer of A(n) ____________________ periodically emits large amounts of...

Question 10

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 11

Why does our theory predict that neutron stars will spin rapidly?

Accepted Answer

The answer of Why does our theory predict that neutron...

Question 12

The singularity of a black hole

Accepted Answer

A)  is found outside the event horizon. 
B)  is located within the event horizon. 
C)  can only be located if the black hole is in a binary system. 
D)  doesn't exist since all black holes have a finite size. 
A)  is found outside the event horizon. 
B)  is located within the event horizon. 
C)  can only be located if the black hole is in a binary system. 
D)  doesn't exist since all black holes have a finite size.

Question 13

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 14

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

Accepted Answer

A)  there would be no light source nearby. 
B)  it would not be rotating rapidly. 
C)  it would be stationary. 
D)  very little matter would be falling into it. 
E)  there would be very few stars behind it whose light the black hole could block out. 
A)  there would be no light source nearby. 
B)  it would not be rotating rapidly. 
C)  it would be stationary. 
D)  very little matter would be falling into it. 
E)  there would be very few stars behind it whose light the black hole could block out.

Question 15

None of the pulsars emit pulses of visible light because

Accepted Answer

A)  pulsars are too hot to emit visible light. 
B)  pulsars contain black holes that won't let visible light escape. 
C)  the gravitational field of a pulsar is so great that the visible light emitted is redshifted. 
D)  pulsars are too far away for the visible light to be bright enough to be detected at Earth. 
E)  A few pulsars do emit visible light pulses. 
A)  pulsars are too hot to emit visible light. 
B)  pulsars contain black holes that won't let visible light escape. 
C)  the gravitational field of a pulsar is so great that the visible light emitted is redshifted. 
D)  pulsars are too far away for the visible light to be bright enough to be detected at Earth. 
E)  A few pulsars do emit visible light pulses.

Question 16

Hypernovae are

Accepted Answer

A)  supernovae that occur when two red dwarfs collide. 
B)  supernovae that occur when 10-solar-mass stars explode. 
C)  supernovae that occur when stars more massive than 25 solar masses explode. 
D)  one theory to explain the production of gamma-ray bursters. 
E)  both c and d above. 
A)  supernovae that occur when two red dwarfs collide. 
B)  supernovae that occur when 10-solar-mass stars explode. 
C)  supernovae that occur when stars more massive than 25 solar masses explode. 
D)  one theory to explain the production of gamma-ray bursters. 
E)  both c and d above.

Question 17

If neutron stars contain no nuclear fuel, why are they hot?

Accepted Answer

The answer of If neutron stars contain no nuclear fuel,...

Question 18

The slowing of clocks in strongly curved space time is known as

Accepted Answer

A)  gravitational radiation. 
B)  time dilation. 
C)  gravitational curvature. 
D)  gravitational redshift. 
E)  hyperspace drag. 
A)  gravitational radiation. 
B)  time dilation. 
C)  gravitational curvature. 
D)  gravitational redshift. 
E)  hyperspace drag.

Question 19

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. 
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.

Question 20

Why does our theory predict that neutron stars will have strong magnetic fields?

Accepted Answer

The answer of Why does our theory predict that neutron...

The Schwarzschild radius of a 2- black hole is approximately

The ____________________ theory describes pulsars as rotating neutron stars with strong magnetic fields that confine high-speed charged particles in two beams emanating from the magnetic poles of the neutron star.

Millisecond pulsars that are very old are

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

A black hole can be thought of as

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

At extremely high densities and temperatures, electrons can be forced to fuse with protons. This reaction produces

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

A(n) ____________________ periodically emits large amounts of X-ray radiation as material accretes around a neutron star or black hole.

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

Why does our theory predict that neutron stars will spin rapidly?

The singularity of a black hole

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

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

None of the pulsars emit pulses of visible light because

Hypernovae are

If neutron stars contain no nuclear fuel, why are they hot?

The slowing of clocks in strongly curved space time is known as

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

Why does our theory predict that neutron stars will have strong magnetic fields?

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

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Exam 11: Neutron Stars and Black Holes

The Schwarzschild radius of a 2- black hole is approximately

The ____________________ theory describes pulsars as rotating neutron stars with strong magnetic fields that confine high-speed charged particles in two beams emanating from the magnetic poles of the neutron star.

Millisecond pulsars that are very old are

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

A black hole can be thought of as

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

At extremely high densities and temperatures, electrons can be forced to fuse with protons. This reaction produces

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

A(n) ____________________ periodically emits large amounts of X-ray radiation as material accretes around a neutron star or black hole.

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

Why does our theory predict that neutron stars will spin rapidly?

The singularity of a black hole

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

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

None of the pulsars emit pulses of visible light because

Hypernovae are

If neutron stars contain no nuclear fuel, why are they hot?

The slowing of clocks in strongly curved space time is known as

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

Why does our theory predict that neutron stars will have strong magnetic fields?

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