Question 1

The singularity of a black hole has an infinitely small radius, but its event horizon is finite.

Accepted Answer

A) True 
 B)False

Question 2

If the Sun were to be instantly replaced by a 1M $\odot$ black hole, the gravitational pull of the black hole on Earth would be:

Accepted Answer

A)  much greater than it is now 
B)  the same as it is now 
C)  much smaller than it is now 
D)  larger or smaller, depending on the location of the Moon 
E)  irrelevant because Earth would be quickly fall into the Sun and be destroyed 
A)  much greater than it is now 
B)  the same as it is now 
C)  much smaller than it is now 
D)  larger or smaller, depending on the location of the Moon 
E)  irrelevant because Earth would be quickly fall into the Sun and be destroyed

Question 3

You observe a distant galaxy apparently moving away at 1/3 the speed of light (v =c/3). If you could measure the speed that this galaxy's light is passing the Earth, you would get:

Accepted Answer

A)  c/3 
B)  2c/3 
C)  c 
D)  4c/3 
E)  5c/3 
A)  c/3 
B)  2c/3 
C)  c 
D)  4c/3 
E)  5c/3

Question 4

Gravitational lensing allows us to see distant objects brightened and distorted because of massive objects in the path that the light from the object travels.

Accepted Answer

A) True 
 B)False

Question 5

Photons have no mass, and Einstein's theory of general relativity says:

Accepted Answer

A)  their paths through spacetime are curved in the presence of a massive body 
B)  their apparent speeds depend on the observer's frame of reference 
C)  they should not be attracted to a massive object 
D)  their wavelengths must remain the same as they travel through spacetime 
E)  their wavelengths would grow longer as they travel through empty space 
A)  their paths through spacetime are curved in the presence of a massive body 
B)  their apparent speeds depend on the observer's frame of reference 
C)  they should not be attracted to a massive object 
D)  their wavelengths must remain the same as they travel through spacetime 
E)  their wavelengths would grow longer as they travel through empty space

Question 6

Black holes emit no light whatsoever.

Accepted Answer

A) True 
 B)False

Question 7

As shown in this figure, an observer in a windowless room notices that light from a flashlight does not follow a straight path, but instead seems to be bent downwards as it crosses the room. What does the observer conclude is happening?

Accepted Answer

A)  The room is experiencing an acceleration from gravity. 
B)  The room is accelerating upward. 
C)  Both A and B at the same time. 
D)  Either A or B; it is impossible to tell the difference. 
E)  Either A or B, depending on whether massive objects in the room fall downward or float upward when released. 
A)  The room is experiencing an acceleration from gravity. 
B)  The room is accelerating upward. 
C)  Both A and B at the same time. 
D)  Either A or B; it is impossible to tell the difference. 
E)  Either A or B, depending on whether massive objects in the room fall downward or float upward when released.

Question 8

Hawking radiation is emitted by a black hole when:

Accepted Answer

A)  the black hole rotates quickly 
B)  the black hole accretes material 
C)  a supernova explodes and forms a black hole out of its core 
D)  synchrotron radiation is emitted by infalling charged particles 
E)  a virtual pair of particles is created from the vacuum of space 
A)  the black hole rotates quickly 
B)  the black hole accretes material 
C)  a supernova explodes and forms a black hole out of its core 
D)  synchrotron radiation is emitted by infalling charged particles 
E)  a virtual pair of particles is created from the vacuum of space

Question 9

The Sun could turn into a black hole at the end of its life.

Accepted Answer

A) True 
 B)False

Question 10

Galileo supposedly experimented with gravity by dropping two objects of different masses from the leaning tower of Pisa at the same instant and observing that they hit the ground at the same time. If Albert Einstein had done the experiment, how would his conclusion have differed from Galileo's?

Accepted Answer

Galileo would say that the acceleration

The singularity of a black hole has an infinitely small radius, but its event horizon is finite.

If the Sun were to be instantly replaced by a 1M _$\odot$ black hole, the gravitational pull of the black hole on Earth would be:

You observe a distant galaxy apparently moving away at 1/3 the speed of light (v =c/3). If you could measure the speed that this galaxy's light is passing the Earth, you would get:

Gravitational lensing allows us to see distant objects brightened and distorted because of massive objects in the path that the light from the object travels.

Photons have no mass, and Einstein's theory of general relativity says:

Black holes emit no light whatsoever.

As shown in this figure, an observer in a windowless room notices that light from a flashlight does not follow a straight path, but instead seems to be bent downwards as it crosses the room. What does the observer conclude is happening?

Hawking radiation is emitted by a black hole when:

The Sun could turn into a black hole at the end of its life.

Galileo supposedly experimented with gravity by dropping two objects of different masses from the leaning tower of Pisa at the same instant and observing that they hit the ground at the same time. If Albert Einstein had done the experiment, how would his conclusion have differed from Galileo's?

Why Learn Astronomy

Patterns in the Skymotions of Earth

Motion of Astronomical Bodies

Gravity and Orbits

Light

The Tools of the Astronomer

The Birth and Evolution of Planetary Systems

The Terrestrial Planets and Earths Moon

Atmospheres of the Terrestrial Planets

Worlds of Gas and Liquid the Giant Planets

Planetary Adornmentsmoons and Rings

Dwarf Planets and Small Solar System Bodies

Taking the Measure of Stars

Our Starthe Sun

Star Formation and the Interstellar Medium

Evolution of Low-Mass Stars

Evolution of High-Mass Stars

The Expanding Universe

Galaxies

The Milky Waya Normal Spiral Galaxy

Modern Cosmology

Large-Scale Structure in the Universe

Life

Filters

Exam 18: Relativity and Black Holes

The singularity of a black hole has an infinitely small radius, but its event horizon is finite.

If the Sun were to be instantly replaced by a 1M ⊙\odot⊙ black hole, the gravitational pull of the black hole on Earth would be:

You observe a distant galaxy apparently moving away at 1/3 the speed of light (v =c/3). If you could measure the speed that this galaxy's light is passing the Earth, you would get:

Gravitational lensing allows us to see distant objects brightened and distorted because of massive objects in the path that the light from the object travels.

Photons have no mass, and Einstein's theory of general relativity says:

Black holes emit no light whatsoever.

As shown in this figure, an observer in a windowless room notices that light from a flashlight does not follow a straight path, but instead seems to be bent downwards as it crosses the room. What does the observer conclude is happening?

Hawking radiation is emitted by a black hole when:

The Sun could turn into a black hole at the end of its life.

Galileo supposedly experimented with gravity by dropping two objects of different masses from the leaning tower of Pisa at the same instant and observing that they hit the ground at the same time. If Albert Einstein had done the experiment, how would his conclusion have differed from Galileo's?

Why Learn Astronomy

Patterns in the Skymotions of Earth

Motion of Astronomical Bodies

Gravity and Orbits

Light

The Tools of the Astronomer

The Birth and Evolution of Planetary Systems

The Terrestrial Planets and Earths Moon

Atmospheres of the Terrestrial Planets

Worlds of Gas and Liquid the Giant Planets

Planetary Adornmentsmoons and Rings

Dwarf Planets and Small Solar System Bodies

Taking the Measure of Stars

Our Starthe Sun

Star Formation and the Interstellar Medium

Evolution of Low-Mass Stars

Evolution of High-Mass Stars

The Expanding Universe

Galaxies

The Milky Waya Normal Spiral Galaxy

Modern Cosmology

Large-Scale Structure in the Universe

Life

Filters

If the Sun were to be instantly replaced by a 1M _$\odot$ black hole, the gravitational pull of the black hole on Earth would be: