Question 1

The first radio energy to be detected from outer space came from the

Accepted Answer

A)  center of the Milky Way Galaxy, in the direction of Sagittarius. 
B)  Sun. 
C)  Moon. 
D)  quasar 3C 273. 
A)  center of the Milky Way Galaxy, in the direction of Sagittarius. 
B)  Sun. 
C)  Moon. 
D)  quasar 3C 273.

Question 2

Many amateur astronomers have telescopes with mirrors 20 cm (1/5 m) in diameter. In comparison, one of the largest astronomical telescopes in the world is the Keck telescope, with a diameter of 10 m. How much greater is the light-gathering power of the Keck telescope than the power of a 20-cm telescope?

Accepted Answer

A)  50 times greater 
B)  7 times greater 
C)  125,000 times greater 
D)  2500 times greater 
A)  50 times greater 
B)  7 times greater 
C)  125,000 times greater 
D)  2500 times greater

Question 3

MOST moderate energy cosmic rays originate from

Accepted Answer

A)  the Sun. 
B)  supernova debris colliding with gas in the interstellar medium. 
C)  charge-coupled devices. 
D)  the Big Bang. 
A)  the Sun. 
B)  supernova debris colliding with gas in the interstellar medium. 
C)  charge-coupled devices. 
D)  the Big Bang.

Question 4

What is a CCD (charge-coupled device)?

Accepted Answer

A)  detector in which a small electric current is controlled by a bimetallic strip that expands and contracts in response to infrared radiation 
B)  electronic filter to single out one wavelength or set of wavelengths for studying astronomical objects 
C)  device in which an image from a photographic plate or film is transferred to a computer by moving static electric charges directly into the computer memory in a manner similar to modern copying machines 
D)  array of small light-sensitive elements that can be used in place of photographic film to obtain and store a picture 
A)  detector in which a small electric current is controlled by a bimetallic strip that expands and contracts in response to infrared radiation 
B)  electronic filter to single out one wavelength or set of wavelengths for studying astronomical objects 
C)  device in which an image from a photographic plate or film is transferred to a computer by moving static electric charges directly into the computer memory in a manner similar to modern copying machines 
D)  array of small light-sensitive elements that can be used in place of photographic film to obtain and store a picture

Question 5

Thomas Young demonstrated that light behaves as a wave by showing that

Accepted Answer

A)  light striking a metal surface releases electrons from the metal, with violet light producing more energetic electrons than red light. 
B)  light passing through two narrow, closely spaced slits produces a pattern of light and dark bands on a screen by wave interference. 
C)  the speed of light in a vacuum is the same for all observers. 
D)  the speed of light decreases when it enters a denser, transparent medium. 
A)  light striking a metal surface releases electrons from the metal, with violet light producing more energetic electrons than red light. 
B)  light passing through two narrow, closely spaced slits produces a pattern of light and dark bands on a screen by wave interference. 
C)  the speed of light in a vacuum is the same for all observers. 
D)  the speed of light decreases when it enters a denser, transparent medium.

Question 6

The two ranges of electromagnetic radiation for which Earth's atmosphere is reasonably transparent are

Accepted Answer

A)  X- ray and visible light. 
B)  visible light and radio wave. 
C)  visible light and far infrared radiation. 
D)  UV radiation and radio wave. 
A)  X- ray and visible light. 
B)  visible light and radio wave. 
C)  visible light and far infrared radiation. 
D)  UV radiation and radio wave.

Question 7

A discovery useful to telescope makers was made by Isaac Newton, namely that the surface of a liquid spun in a circle assumes the shape of a

Accepted Answer

A)  sphere. 
B)  parabola. 
C)  ellipse. 
D)  hyperbola. 
A)  sphere. 
B)  parabola. 
C)  ellipse. 
D)  hyperbola.

Question 8

Placing a secondary mirror in front of the primary mirror

Accepted Answer

A)  creates a blank spot in the image. 
B)  darkens the image. 
C)  brightens the image due to increased reflection. 
D)  causes problems that must be corrected by using a Schmidt corrector plate. 
A)  creates a blank spot in the image. 
B)  darkens the image. 
C)  brightens the image due to increased reflection. 
D)  causes problems that must be corrected by using a Schmidt corrector plate.

Question 9

Light from each part of the source being observed falls on each part of the primary mirror of a Newtonian telescope not obstructed by the secondary mirror. The important consequence of this is that

Accepted Answer

A)  the image does not have a dark spot indicating the presence of the secondary mirror. 
B)  the image is not darkened (overall) because of the presence of the secondary mirror. 
C)  cheaper spherical mirrors can be used rather than a more costly parabolic mirror. 
D)  the secondary mirror can be made as large as needed without influencing the quality of the image. 
A)  the image does not have a dark spot indicating the presence of the secondary mirror. 
B)  the image is not darkened (overall) because of the presence of the secondary mirror. 
C)  cheaper spherical mirrors can be used rather than a more costly parabolic mirror. 
D)  the secondary mirror can be made as large as needed without influencing the quality of the image.

Question 10

The first evidence for gravitational waves came from

Accepted Answer

A)  mapping the orbits of stars near the center of our Galaxy. 
B)  periodic ripples in the distances between objects. 
C)  the cosmic microwave background. 
D)  the changing orbits of neutron stars. 
A)  mapping the orbits of stars near the center of our Galaxy. 
B)  periodic ripples in the distances between objects. 
C)  the cosmic microwave background. 
D)  the changing orbits of neutron stars.

Question 11

In 1675, Ole Rømer measured the speed of light by

Accepted Answer

A)  timing eclipses of Jupiter's satellites by the planet, which appeared to occur later when Earth was farther from Jupiter. 
B)  opening a shutter on a lantern on a hilltop and measuring the time taken for light from an assistant's shuttered lantern to return. 
C)  reflecting light from a mirror rotating at a known speed and measuring the angle of deflection of the light beam. 
D)  measuring how long it took the light to reach Earth from stars located at different distances from Earth. 
A)  timing eclipses of Jupiter's satellites by the planet, which appeared to occur later when Earth was farther from Jupiter. 
B)  opening a shutter on a lantern on a hilltop and measuring the time taken for light from an assistant's shuttered lantern to return. 
C)  reflecting light from a mirror rotating at a known speed and measuring the angle of deflection of the light beam. 
D)  measuring how long it took the light to reach Earth from stars located at different distances from Earth.

Question 12

In 1670, Isaac Newton performed a crucial experiment on the nature of light when he

Accepted Answer

A)  proved mathematically that light could be described by oscillating electric and magnetic fields. 
B)  demonstrated that white light was made up of colors that could be split by a prism and that these colors were not produced by the glass through which the light passed. 
C)  showed that a prism through which light passed added a spectrum of colors to the light. 
D)  demonstrated the wave nature of light by passing light through two slits and obtaining a pattern of bright and dark bands on a screen that he ascribed to interference between the two beams. 
A)  proved mathematically that light could be described by oscillating electric and magnetic fields. 
B)  demonstrated that white light was made up of colors that could be split by a prism and that these colors were not produced by the glass through which the light passed. 
C)  showed that a prism through which light passed added a spectrum of colors to the light. 
D)  demonstrated the wave nature of light by passing light through two slits and obtaining a pattern of bright and dark bands on a screen that he ascribed to interference between the two beams.

Question 13

If one observatory site is described as having better "seeing" than another observatory site, what is it that is better at the first site?

Accepted Answer

A)  The sky is more transparent and there is less haze in the atmosphere at that site, providing brighter and sharper images. 
B)  The winds are lighter at the better site, thereby producing less telescope vibration. 
C)  There is less air turbulence at that site, causing less twinkling and blurring of the images. 
D)  There are more clear nights at that site. 
A)  The sky is more transparent and there is less haze in the atmosphere at that site, providing brighter and sharper images. 
B)  The winds are lighter at the better site, thereby producing less telescope vibration. 
C)  There is less air turbulence at that site, causing less twinkling and blurring of the images. 
D)  There are more clear nights at that site.

Question 14

Which way does a light ray bend when it crosses the plane smooth surface of a dense transparent material (from air or a vacuum) at an angle to the perpendicular?

Accepted Answer

A)  The light ray does not bend at all because the material is transparent. 
B)  The light ray bends toward the perpendicular. 
C)  The light ray bends so that it travels perpendicular to the surface. 
D)  The light ray bends away from the perpendicular. 
A)  The light ray does not bend at all because the material is transparent. 
B)  The light ray bends toward the perpendicular. 
C)  The light ray bends so that it travels perpendicular to the surface. 
D)  The light ray bends away from the perpendicular.

Question 15

Light enters the smooth flat surface of a block of glass from the vacuum of space (e.g., a spacecraft window). What is the speed of light inside the glass compared to that in a vacuum?

Accepted Answer

A)  The speed will depend on the angle that the light ray makes with the perpendicular to the surface, becoming slower as the angle increases. 
B)  same because the speed of light is constant, by definition 
C)  faster because the glass is denser than the vacuum 
D)  slower because the glass is denser than the vacuum 
A)  The speed will depend on the angle that the light ray makes with the perpendicular to the surface, becoming slower as the angle increases. 
B)  same because the speed of light is constant, by definition 
C)  faster because the glass is denser than the vacuum 
D)  slower because the glass is denser than the vacuum

Question 16

Visible light occupies what portion of the full wavelength range of electromagnetic radiation?

Accepted Answer

A)  a very narrow range 
B)  two narrow but separate ranges between ultraviolet and infrared radiations, the red and the blue, which mix to give all the other colors 
C)  about half of the possible range 
D)  almost the full range between radio and X-ray 
A)  a very narrow range 
B)  two narrow but separate ranges between ultraviolet and infrared radiations, the red and the blue, which mix to give all the other colors 
C)  about half of the possible range 
D)  almost the full range between radio and X-ray

Question 17

Which of these telescopes consists of a concave, spherical primary mirror and a glass corrector plate to correct for the spherical aberration in the primary?

Accepted Answer

A)  Newtonian telescope 
B)  refracting telescope 
C)  Cassegrain telescope 
D)  Schmidt telescope 
A)  Newtonian telescope 
B)  refracting telescope 
C)  Cassegrain telescope 
D)  Schmidt telescope

Question 18

What is refraction of light?

Accepted Answer

A)  breaking of white light into its composite colors 
B)  change in direction of a light ray when it reflects on a material more dense than the one in which it is traveling 
C)  absorption of light as it traverses a dense, transparent material 
D)  change in direction of a light ray as it passes at an angle from one transparent material to another that has a different optical density 
A)  breaking of white light into its composite colors 
B)  change in direction of a light ray when it reflects on a material more dense than the one in which it is traveling 
C)  absorption of light as it traverses a dense, transparent material 
D)  change in direction of a light ray as it passes at an angle from one transparent material to another that has a different optical density

Question 19

Do people use astronomical gamma ray detectors on Earth's surface?

Accepted Answer

A)  No. The atmosphere blocks all gamma rays from space. Thus, people cannot use gamma ray detectors on Earth's surface. 
B)  Yes. Gamma rays have a narrow "window" through Earth's atmosphere. So, people can detect enough of them to form images. 
C)  Yes, but these detectors are actually pointed downward to detect rays coming through Earth. Only cosmic gamma rays have enough energy to penetrate Earth, which acts as a filter for gamma rays generated by terrestrial sources. 
D)  Yes, but these detectors actually detect Cherenkov radiation produced by particles struck by gamma rays high in the atmosphere. Thus, the gamma ray detection is very indirect. 
A)  No. The atmosphere blocks all gamma rays from space. Thus, people cannot use gamma ray detectors on Earth's surface. 
B)  Yes. Gamma rays have a narrow "window" through Earth's atmosphere. So, people can detect enough of them to form images. 
C)  Yes, but these detectors are actually pointed downward to detect rays coming through Earth. Only cosmic gamma rays have enough energy to penetrate Earth, which acts as a filter for gamma rays generated by terrestrial sources. 
D)  Yes, but these detectors actually detect Cherenkov radiation produced by particles struck by gamma rays high in the atmosphere. Thus, the gamma ray detection is very indirect.

Question 20

What technique is necessary to produce a telescope for focusing X-rays from astronomical sources?

Accepted Answer

A)  The telescope must be placed at high-altitude mountain sites because the X-rays penetrate only this far into the atmosphere. 
B)  The main mirror must be cooled to prevent the highly energetic X-ray photons from heating and distorting it, thereby producing poor images. 
C)  The X-rays must be reflected at grazing incidence to the mirror surface; otherwise they will simply pass straight through the mirror. 
D)  The mirror surface has to have a thick aluminum coating in order to reflect the highly penetrating X-rays. 
A)  The telescope must be placed at high-altitude mountain sites because the X-rays penetrate only this far into the atmosphere. 
B)  The main mirror must be cooled to prevent the highly energetic X-ray photons from heating and distorting it, thereby producing poor images. 
C)  The X-rays must be reflected at grazing incidence to the mirror surface; otherwise they will simply pass straight through the mirror. 
D)  The mirror surface has to have a thick aluminum coating in order to reflect the highly penetrating X-rays.

The first radio energy to be detected from outer space came from the

MOST moderate energy cosmic rays originate from

What is a CCD (charge-coupled device)?

Thomas Young demonstrated that light behaves as a wave by showing that

The two ranges of electromagnetic radiation for which Earth's atmosphere is reasonably transparent are

A discovery useful to telescope makers was made by Isaac Newton, namely that the surface of a liquid spun in a circle assumes the shape of a

Placing a secondary mirror in front of the primary mirror

Light from each part of the source being observed falls on each part of the primary mirror of a Newtonian telescope not obstructed by the secondary mirror. The important consequence of this is that

The first evidence for gravitational waves came from

In 1675, Ole Rømer measured the speed of light by

In 1670, Isaac Newton performed a crucial experiment on the nature of light when he

If one observatory site is described as having better "seeing" than another observatory site, what is it that is better at the first site?

Which way does a light ray bend when it crosses the plane smooth surface of a dense transparent material (from air or a vacuum) at an angle to the perpendicular?

Light enters the smooth flat surface of a block of glass from the vacuum of space (e.g., a spacecraft window). What is the speed of light inside the glass compared to that in a vacuum?

Visible light occupies what portion of the full wavelength range of electromagnetic radiation?

Which of these telescopes consists of a concave, spherical primary mirror and a glass corrector plate to correct for the spherical aberration in the primary?

What is refraction of light?

Do people use astronomical gamma ray detectors on Earth's surface?

What technique is necessary to produce a telescope for focusing X-rays from astronomical sources?

Discovering the Night Sky

Gravitation and the Motion of the Planets

Atomic Physics and Spectra

Exoplanets and the Formation of Planetary Systems

Formation of the Solar System

Earth and the Moon

The Other Terrestrial Planets

The Outer Planets

Vagabonds of the Solar System

The Sun: Our Extraordinary Star

Characterizing Stars

The Lives of Stars From Birth Through Middle Age

The Death of Stars

Black Holes: Matters of Gravity

The Milky Way Galaxy

Galaxies

Quasars and Other Active Galaxies

Cosmology

Astrobiology

Filters

Exam 3: Light and Telescopes

The first radio energy to be detected from outer space came from the

MOST moderate energy cosmic rays originate from

What is a CCD (charge-coupled device)?

Thomas Young demonstrated that light behaves as a wave by showing that

The two ranges of electromagnetic radiation for which Earth's atmosphere is reasonably transparent are

A discovery useful to telescope makers was made by Isaac Newton, namely that the surface of a liquid spun in a circle assumes the shape of a

Placing a secondary mirror in front of the primary mirror

Light from each part of the source being observed falls on each part of the primary mirror of a Newtonian telescope not obstructed by the secondary mirror. The important consequence of this is that

The first evidence for gravitational waves came from

In 1675, Ole Rømer measured the speed of light by

In 1670, Isaac Newton performed a crucial experiment on the nature of light when he

If one observatory site is described as having better "seeing" than another observatory site, what is it that is better at the first site?

Which way does a light ray bend when it crosses the plane smooth surface of a dense transparent material (from air or a vacuum) at an angle to the perpendicular?

Light enters the smooth flat surface of a block of glass from the vacuum of space (e.g., a spacecraft window). What is the speed of light inside the glass compared to that in a vacuum?

Visible light occupies what portion of the full wavelength range of electromagnetic radiation?

Which of these telescopes consists of a concave, spherical primary mirror and a glass corrector plate to correct for the spherical aberration in the primary?

What is refraction of light?

Do people use astronomical gamma ray detectors on Earth's surface?

What technique is necessary to produce a telescope for focusing X-rays from astronomical sources?

Discovering the Night Sky

Gravitation and the Motion of the Planets

Atomic Physics and Spectra

Exoplanets and the Formation of Planetary Systems

Formation of the Solar System

Earth and the Moon

The Other Terrestrial Planets

The Outer Planets

Vagabonds of the Solar System

The Sun: Our Extraordinary Star

Characterizing Stars

The Lives of Stars From Birth Through Middle Age

The Death of Stars

Black Holes: Matters of Gravity

The Milky Way Galaxy

Galaxies

Quasars and Other Active Galaxies

Cosmology

Astrobiology

Filters