Question 1

A black hole may be visible because electromagnetic radiation is emitted from an ________ surrounding it, heated up enough to emit X-rays.

Accepted Answer

The answer of A black hole may be visible because...

Question 2

Describe the properties of space in the vicinity of a black hole.

Accepted Answer

The geometry of space is warped or curve

Question 3

The equivalence principle says that a person in an elevator that is in freefall feels the same acceleration as

Accepted Answer

A)  a person in an elevator going up with an acceleration of g. 
B)  a person in space, far from any gravitational source accelerating at g. 
C)  a person in an elevator going down with an acceleration of g. 
D)  a person in space, far away from any gravitational source with no acceleration. 
E)  a person in orbit of Earth accelerating at g upward. 
A)  a person in an elevator going up with an acceleration of g. 
B)  a person in space, far from any gravitational source accelerating at g. 
C)  a person in an elevator going down with an acceleration of g. 
D)  a person in space, far away from any gravitational source with no acceleration. 
E)  a person in orbit of Earth accelerating at g upward.

Question 4

Very rapid time variations help establish the tiny size of many X-ray sources, showing they must be collapsed objects of some kind.

Accepted Answer

A) True 
 B)False

Question 5

The energy from the accretion disk around a black hole would show gravitational red shift due to its immense gravity and tidal distortion of space there.

Accepted Answer

A) True 
 B)False

Question 6

Black holes suck up all matter in sight.

Accepted Answer

A) True 
 B)False

Question 7

An observer on a planet sees a spaceship approaching at 0.5c. A beam of light projected by the ship would be measured by this observer to travel at

Accepted Answer

A)  0.25c. 
B)  0.5c. 
C)  c. 
D)  1.5c. 
E)  2.5c. 
A)  0.25c. 
B)  0.5c. 
C)  c. 
D)  1.5c. 
E)  2.5c.

Question 8

If a spaceship travels near the speed of light away from the Earth, an observer on Earth would see the length of the spaceship ________.

Accepted Answer

The answer of If a spaceship travels near the speed...

Question 9

Something falling into a black hole will be ________ by tides.

Accepted Answer

The answer of Something falling into a black hole will...

Question 10

When observing an object, such as a space ship that is moving very quickly relative to you, the length of objects on that object will appear to be

Accepted Answer

A)  longer than when they are at rest. 
B)  the same length as when they are at rest. 
C)  shorter than when they are at rest. 
D)  narrower than when they are at rest. 
E)  wider than when they are at rest. 
A)  longer than when they are at rest. 
B)  the same length as when they are at rest. 
C)  shorter than when they are at rest. 
D)  narrower than when they are at rest. 
E)  wider than when they are at rest.

Question 11

If something falls into a black hole, it remains intact until it reaches the event horizon.

Accepted Answer

A) True 
 B)False

Question 12

What explanation does general relativity provide for gravity?

Accepted Answer

A)  Gravity is the result of curved spacetime. 
B)  Gravity is directly proportional to the mass of the attracting body. 
C)  Gravity is inversely proportion to the radius of the body. 
D)  Gravity is the opposite of the electromagnetic force. 
E)  Gravity can affect only massive particles, not massless photons. 
A)  Gravity is the result of curved spacetime. 
B)  Gravity is directly proportional to the mass of the attracting body. 
C)  Gravity is inversely proportion to the radius of the body. 
D)  Gravity is the opposite of the electromagnetic force. 
E)  Gravity can affect only massive particles, not massless photons.

Question 13

How is the Schwartzschild radius calculated?

Accepted Answer

The Schwartzschild r

Question 14

If light from a distant star passes close to a massive body, the light beam will

Accepted Answer

A)  bend towards the star due to gravity. 
B)  continue moving in a straight line. 
C)  change color to a shorter wavelength. 
D)  slow down. 
E)  accelerate due to gravity. 
A)  bend towards the star due to gravity. 
B)  continue moving in a straight line. 
C)  change color to a shorter wavelength. 
D)  slow down. 
E)  accelerate due to gravity.

Question 15

Explain how the essential features of special relativity imply that a beam of light from a fast moving spaceship will always be observed to moving at the speed of light.

Accepted Answer

The essential features are: The laws of

Question 16

Which of the following is NOT an argument for Cygnus X-1's being a true black hole?

Accepted Answer

A)  Spectroscopic data suggests hot gas is flowing from the companion B star onto Cygnus X-1. 
B)  The mass of the visible B star is even greater than Cygnus X-1, at around 25 solar masses. 
C)  Cygnus X-1's mass is estimated to be about 10 solar masses. 
D)  X-rays from Cygnus X-1 vary on time scales as short as a millisecond. 
E)  X-ray observations around the object support a temperature of several million K. 
A)  Spectroscopic data suggests hot gas is flowing from the companion B star onto Cygnus X-1. 
B)  The mass of the visible B star is even greater than Cygnus X-1, at around 25 solar masses. 
C)  Cygnus X-1's mass is estimated to be about 10 solar masses. 
D)  X-rays from Cygnus X-1 vary on time scales as short as a millisecond. 
E)  X-ray observations around the object support a temperature of several million K.

Question 17

Special relativity says that time is a separate ________ in the workings of the universe.

Accepted Answer

The answer of Special relativity says that time is a...

A black hole may be visible because electromagnetic radiation is emitted from an ________ surrounding it, heated up enough to emit X-rays.

Describe the properties of space in the vicinity of a black hole.

The equivalence principle says that a person in an elevator that is in freefall feels the same acceleration as

Very rapid time variations help establish the tiny size of many X-ray sources, showing they must be collapsed objects of some kind.

The energy from the accretion disk around a black hole would show gravitational red shift due to its immense gravity and tidal distortion of space there.

Black holes suck up all matter in sight.

An observer on a planet sees a spaceship approaching at 0.5c. A beam of light projected by the ship would be measured by this observer to travel at

If a spaceship travels near the speed of light away from the Earth, an observer on Earth would see the length of the spaceship ________.

Something falling into a black hole will be ________ by tides.

When observing an object, such as a space ship that is moving very quickly relative to you, the length of objects on that object will appear to be

If something falls into a black hole, it remains intact until it reaches the event horizon.

What explanation does general relativity provide for gravity?

How is the Schwartzschild radius calculated?

If light from a distant star passes close to a massive body, the light beam will

Explain how the essential features of special relativity imply that a beam of light from a fast moving spaceship will always be observed to moving at the speed of light.

Which of the following is NOT an argument for Cygnus X-1's being a true black hole?

Special relativity says that time is a separate ________ in the workings of the universe.

The Night Sky

Light and Telescopes

The Solar System

Earth and Its Moon

The Eight Planets

Small Bodies in the Solar System

Formation of Planetary Systems

The Sun

Measuring the Stars

Star Formation and Evolution

Stellar Explosions

The Milky Way Galaxy

Galaxies

Cosmology and the Universe

Filters

Exam 12: Black Holes

A black hole may be visible because electromagnetic radiation is emitted from an ________ surrounding it, heated up enough to emit X-rays.

Describe the properties of space in the vicinity of a black hole.

The equivalence principle says that a person in an elevator that is in freefall feels the same acceleration as

Very rapid time variations help establish the tiny size of many X-ray sources, showing they must be collapsed objects of some kind.

The energy from the accretion disk around a black hole would show gravitational red shift due to its immense gravity and tidal distortion of space there.

Black holes suck up all matter in sight.

An observer on a planet sees a spaceship approaching at 0.5c. A beam of light projected by the ship would be measured by this observer to travel at

If a spaceship travels near the speed of light away from the Earth, an observer on Earth would see the length of the spaceship ________.

Something falling into a black hole will be ________ by tides.

When observing an object, such as a space ship that is moving very quickly relative to you, the length of objects on that object will appear to be

If something falls into a black hole, it remains intact until it reaches the event horizon.

What explanation does general relativity provide for gravity?

How is the Schwartzschild radius calculated?

If light from a distant star passes close to a massive body, the light beam will

Explain how the essential features of special relativity imply that a beam of light from a fast moving spaceship will always be observed to moving at the speed of light.

Which of the following is NOT an argument for Cygnus X-1's being a true black hole?

Special relativity says that time is a separate ________ in the workings of the universe.

The Night Sky

Light and Telescopes

The Solar System

Earth and Its Moon

The Eight Planets

Small Bodies in the Solar System

Formation of Planetary Systems

The Sun

Measuring the Stars

Star Formation and Evolution

Stellar Explosions

The Milky Way Galaxy

Galaxies

Cosmology and the Universe

Filters