Question 1

The "guest star" that appeared in 1054 was seen

Accepted Answer

A)  in China. 
B)  in Constantinople. 
C)  by Anasazi in the current U.S.Southwest. 
D)  All of these 
A)  in China. 
B)  in Constantinople. 
C)  by Anasazi in the current U.S.Southwest. 
D)  All of these D

Question 2

The pulsed nature of the radiation at all wavelengths that is seen to come from a pulsar is produced by the

Accepted Answer

A)  mutual orbiting and eclipsing of two very hot stars in a close binary system. 
B)  rapid pulsation in size and hence brightness of a small white-dwarf star. 
C)  rapid rotation of a neutron star that is producing two oppositely directed beams of radiation. 
D)  extremely hot matter that is rapidly orbiting a black hole just prior to descending into it. 
A)  mutual orbiting and eclipsing of two very hot stars in a close binary system. 
B)  rapid pulsation in size and hence brightness of a small white-dwarf star. 
C)  rapid rotation of a neutron star that is producing two oppositely directed beams of radiation. 
D)  extremely hot matter that is rapidly orbiting a black hole just prior to descending into it. C

Question 3

How do pulsars change over time?

Accepted Answer

They tend to slow down over time because they are radiating away their rotational energy and its pulse period increases.However,if they are in a binary system,they can have interactions that cause them to spin up.

Question 4

The event horizon surrounding a black hole describes the "surface" in space where the escape velocity equals the speed of light.

Accepted Answer

A) True 
 B)False

Question 5

One object that is believed to be a black hole in our Galaxy is

Accepted Answer

A)  the central star in the Ring Nebula in Lyra. 
B)  the central star in the Crab Nebula. 
C)  the undetected tenth planet in our solar system,whose presence has been inferred from its gravitational influence on the outer planets. 
D)  Cygnus X-1,a powerful X-ray source. 
A)  the central star in the Ring Nebula in Lyra. 
B)  the central star in the Crab Nebula. 
C)  the undetected tenth planet in our solar system,whose presence has been inferred from its gravitational influence on the outer planets. 
D)  Cygnus X-1,a powerful X-ray source.

Question 6

If a star ended its main-sequence life with about 5.1 solar masses,the remnant would likely be a

Accepted Answer

A)  white dwarf. 
B)  neutron star. 
C)  black hole. 
D)  None of these 
A)  white dwarf. 
B)  neutron star. 
C)  black hole. 
D)  None of these

Question 7

How does the quantity of gravitational force on a binary companion change when a 6-solar-mass star becomes a 6-solar-mass black hole?

Accepted Answer

A)  It increases. 
B)  It decreases. 
C)  It remains the same. 
D)  It is impossible to determine. 
A)  It increases. 
B)  It decreases. 
C)  It remains the same. 
D)  It is impossible to determine.

Question 8

What is a pulsar?

Accepted Answer

A)  A pulsating white-dwarf star,fluctuating rapidly in brightness 
B)  A rapidly rotating neutron star,producing beams of radio energy and in some cases,light and X-rays 
C)  A rotating black hole,producing two jets of gas in opposite directions and pulses of gravitational energy 
D)  A Cepheid variable star with a period of a few days 
A)  A pulsating white-dwarf star,fluctuating rapidly in brightness 
B)  A rapidly rotating neutron star,producing beams of radio energy and in some cases,light and X-rays 
C)  A rotating black hole,producing two jets of gas in opposite directions and pulses of gravitational energy 
D)  A Cepheid variable star with a period of a few days

Question 9

Which nuclear fusion cycle follows the helium fusion phase as a massive star evolves?

Accepted Answer

A)  Silicon "burning" 
B)  Carbon "burning" 
C)  Iron "burning" 
D)  Oxygen "burning" 
A)  Silicon "burning" 
B)  Carbon "burning" 
C)  Iron "burning" 
D)  Oxygen "burning"

Question 10

What is the Schwarzschild radius of a black hole?

Accepted Answer

A)  The radius of the singularity 
B)  The distance from the singularity to the point from which the X-rays are emitted 
C)  The maximum distance from the singularity from which nothing can escape from the black hole 
D)  The distance from the singularity to the point where any object entering the black hole will gain energy before leaving again 
A)  The radius of the singularity 
B)  The distance from the singularity to the point from which the X-rays are emitted 
C)  The maximum distance from the singularity from which nothing can escape from the black hole 
D)  The distance from the singularity to the point where any object entering the black hole will gain energy before leaving again

Question 11

A graph of the brightness of a supernova versus time is known as a(n)

Accepted Answer

A)  light curve. 
B)  H-R Diagram. 
C)  radial velocity curve. 
D)  Schwartzschild graph. 
A)  light curve. 
B)  H-R Diagram. 
C)  radial velocity curve. 
D)  Schwartzschild graph.

Question 12

What feature distinguishes a black hole from all other objects in the universe?

Accepted Answer

A)  It emits large quantities of X-rays. 
B)  The escape velocity from this object is greater than the speed of light. 
C)  The shape of its gravitational field is always different from that of an ordinary massive object,even at large distances from it. 
D)  Its total mass exceeds 3 solar masses. 
A)  It emits large quantities of X-rays. 
B)  The escape velocity from this object is greater than the speed of light. 
C)  The shape of its gravitational field is always different from that of an ordinary massive object,even at large distances from it. 
D)  Its total mass exceeds 3 solar masses.

Question 13

Black holes are so named because

Accepted Answer

A)  they emit a perfect blackbody spectrum. 
B)  no light or any other electromagnetic radiation can escape from inside them. 
C)  all their electromagnetic radiation is gravitationally redshifted to the infrared,which leaves no light in the optical region. 
D)  they emit no visible light,their only spectral lines are in the radio and infrared. 
A)  they emit a perfect blackbody spectrum. 
B)  no light or any other electromagnetic radiation can escape from inside them. 
C)  all their electromagnetic radiation is gravitationally redshifted to the infrared,which leaves no light in the optical region. 
D)  they emit no visible light,their only spectral lines are in the radio and infrared.

Question 14

The diameter of a typical neutron star of 1 solar mass is predicted to be approximately

Accepted Answer

A)  1 km. 
B)  that of the Sun. 
C)  that of an average city,about 30 km. 
D)  that of Earth,12,800 km. 
A)  1 km. 
B)  that of the Sun. 
C)  that of an average city,about 30 km. 
D)  that of Earth,12,800 km.

Question 15

Which of the following is NEVER a consequence of a supernova explosion?

Accepted Answer

A)  Condensation of matter into a solid nuclear star composed entirely of neutrons 
B)  Triggering of star formation by shock waves moving through interstellar space 
C)  Formation of a planetary nebula 
D)  Manufacture of the nuclei of heavy elements 
A)  Condensation of matter into a solid nuclear star composed entirely of neutrons 
B)  Triggering of star formation by shock waves moving through interstellar space 
C)  Formation of a planetary nebula 
D)  Manufacture of the nuclei of heavy elements

Question 16

Stars with masses between 8 and 14 times the mass of the Sun will end their lives as neutron stars.

Accepted Answer

A) True 
 B)False

Question 17

Type Ia supernovae are generally brighter than Type II supernovae.

Accepted Answer

A) True 
 B)False

Question 18

Can a white dwarf explode?

Accepted Answer

A)  Only if another star collides with it;stars are so far apart in space that this is unlikely ever to have happened in our Galaxy. 
B)  Yes,but only if nuclear reactions in the white dwarf core reach the stage of silicon burning,producing iron. 
C)  No,white dwarfs are held up by electron degeneracy pressure,and this configuration is stable against collapse or explosion. 
D)  Yes,but only if it is in a binary star system. 
A)  Only if another star collides with it;stars are so far apart in space that this is unlikely ever to have happened in our Galaxy. 
B)  Yes,but only if nuclear reactions in the white dwarf core reach the stage of silicon burning,producing iron. 
C)  No,white dwarfs are held up by electron degeneracy pressure,and this configuration is stable against collapse or explosion. 
D)  Yes,but only if it is in a binary star system.

Question 19

In 1054,the imperial astronomer to the Chinese court recorded observing a "guest star" in the sky.We know now that this "guest star" was a supernova explosion within our Galaxy.

Accepted Answer

A) True 
 B)False

Question 20

During the late stages of evolution (e.g. ,oxygen burning)in massive stars,nuclear reactions produce many free neutrons.What very important effect do these neutrons have on the composition of the star?

Accepted Answer

A)  The neutrons,being uncharged,escape from the star,thus carrying away energy from the core of the star and lowering its temperature. 
B)  The neutrons are captured by atomic nuclei and can produce heavy elements that would not form from nuclear fusion alone. 
C)  The neutrons are captured by atomic nuclei,causing the nuclei to split by fission reactions into lighter elements that would otherwise be very rare in the universe. 
D)  The neutrons decay into protons and electrons,thus increasing the amount of hydrogen in the core and extending the life of the star. 
A)  The neutrons,being uncharged,escape from the star,thus carrying away energy from the core of the star and lowering its temperature. 
B)  The neutrons are captured by atomic nuclei and can produce heavy elements that would not form from nuclear fusion alone. 
C)  The neutrons are captured by atomic nuclei,causing the nuclei to split by fission reactions into lighter elements that would otherwise be very rare in the universe. 
D)  The neutrons decay into protons and electrons,thus increasing the amount of hydrogen in the core and extending the life of the star.

The "guest star" that appeared in 1054 was seen

The pulsed nature of the radiation at all wavelengths that is seen to come from a pulsar is produced by the

How do pulsars change over time?

The event horizon surrounding a black hole describes the "surface" in space where the escape velocity equals the speed of light.

One object that is believed to be a black hole in our Galaxy is

If a star ended its main-sequence life with about 5.1 solar masses,the remnant would likely be a

How does the quantity of gravitational force on a binary companion change when a 6-solar-mass star becomes a 6-solar-mass black hole?

What is a pulsar?

Which nuclear fusion cycle follows the helium fusion phase as a massive star evolves?

What is the Schwarzschild radius of a black hole?

A graph of the brightness of a supernova versus time is known as a(n)

What feature distinguishes a black hole from all other objects in the universe?

Black holes are so named because

The diameter of a typical neutron star of 1 solar mass is predicted to be approximately

Which of the following is NEVER a consequence of a supernova explosion?

Stars with masses between 8 and 14 times the mass of the Sun will end their lives as neutron stars.

Type Ia supernovae are generally brighter than Type II supernovae.

Can a white dwarf explode?

In 1054,the imperial astronomer to the Chinese court recorded observing a "guest star" in the sky.We know now that this "guest star" was a supernova explosion within our Galaxy.

During the late stages of evolution (e.g. ,oxygen burning)in massive stars,nuclear reactions produce many free neutrons.What very important effect do these neutrons have on the composition of the star?

Predicting the Motions of the Stars, Sun, and Moon

Decoding the Hidden Messages in Starlight

Analyzing Scales and Motions of the Universe

Exploring Our Evolving Solar System

Uncovering Earths Systems

Exploring Terrestrial Surface Processes and Atmospheres

Observing the Dynamic Giant Planets

Looking for Life Beyond Earth

Probing the Dynamic Sun

Observing Properties of Distant Stars

Inferring Patterns in Star Life Cycles

Exploring Our Galaxy

Investigating Other Galaxies

Observing the Evolution of the Universe

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Exam 12: Predicting the Violent End of the Largest Stars

The "guest star" that appeared in 1054 was seen

The pulsed nature of the radiation at all wavelengths that is seen to come from a pulsar is produced by the

How do pulsars change over time?

The event horizon surrounding a black hole describes the "surface" in space where the escape velocity equals the speed of light.

One object that is believed to be a black hole in our Galaxy is

If a star ended its main-sequence life with about 5.1 solar masses,the remnant would likely be a

How does the quantity of gravitational force on a binary companion change when a 6-solar-mass star becomes a 6-solar-mass black hole?

What is a pulsar?

Which nuclear fusion cycle follows the helium fusion phase as a massive star evolves?

What is the Schwarzschild radius of a black hole?

A graph of the brightness of a supernova versus time is known as a(n)

What feature distinguishes a black hole from all other objects in the universe?

Black holes are so named because

The diameter of a typical neutron star of 1 solar mass is predicted to be approximately

Which of the following is NEVER a consequence of a supernova explosion?

Stars with masses between 8 and 14 times the mass of the Sun will end their lives as neutron stars.

Type Ia supernovae are generally brighter than Type II supernovae.

Can a white dwarf explode?

In 1054,the imperial astronomer to the Chinese court recorded observing a "guest star" in the sky.We know now that this "guest star" was a supernova explosion within our Galaxy.

During the late stages of evolution (e.g. ,oxygen burning)in massive stars,nuclear reactions produce many free neutrons.What very important effect do these neutrons have on the composition of the star?

Predicting the Motions of the Stars, Sun, and Moon

Decoding the Hidden Messages in Starlight

Analyzing Scales and Motions of the Universe

Exploring Our Evolving Solar System

Uncovering Earths Systems

Exploring Terrestrial Surface Processes and Atmospheres

Observing the Dynamic Giant Planets

Looking for Life Beyond Earth

Probing the Dynamic Sun

Observing Properties of Distant Stars

Inferring Patterns in Star Life Cycles

Exploring Our Galaxy

Investigating Other Galaxies

Observing the Evolution of the Universe

Filters