Question 1

What is a diffraction grating?

Accepted Answer

A)  a flat, rectangular array of closely spaced photosensitive cells 
B)  a piece of glass with thousands of closely spaced, parallel grooves 
C)  an array of many radio telescopes used to observe a single source simultaneously 
D)  a triangular prism of solid glass used to disperse light into its colors 
A)  a flat, rectangular array of closely spaced photosensitive cells 
B)  a piece of glass with thousands of closely spaced, parallel grooves 
C)  an array of many radio telescopes used to observe a single source simultaneously 
D)  a triangular prism of solid glass used to disperse light into its colors

Question 2

What is the relationship between color and wavelength for light?

Accepted Answer

A)  Wavelength increases from violet to yellow-green, then decreases again to red. 
B)  Wavelength decreases from violet to red. 
C)  Wavelength increases from violet to red. 
D)  Wavelength depends only on brightness and is independent of color. 
A)  Wavelength increases from violet to yellow-green, then decreases again to red. 
B)  Wavelength decreases from violet to red. 
C)  Wavelength increases from violet to red. 
D)  Wavelength depends only on brightness and is independent of color.

Question 3

How is chromatic aberration MOST often corrected in a modern refracting telescope?

Accepted Answer

A)  by using a combination of two lenses made from different types of glass 
B)  by painting the inside of the telescope jet black to minimize reflections 
C)  by grinding the lens surfaces into a parabolic shape 
D)  by using a prism to recombine the colors into white light 
A)  by using a combination of two lenses made from different types of glass 
B)  by painting the inside of the telescope jet black to minimize reflections 
C)  by grinding the lens surfaces into a parabolic shape 
D)  by using a prism to recombine the colors into white light

Question 4

When light passes through a prism of glass,the:

Accepted Answer

A)  different colors, or wavelengths of light, are separated in angle by the prism. 
B)  different colors are caused by multiple reflections in the prism and interference between the resulting beams. 
C)  prism absorbs colors from different parts of the broad beam coming out of the prism, leaving the complementary colors that we see. 
D)  prism adds colors to different parts of the broadly scattered beam coming out of it. 
A)  different colors, or wavelengths of light, are separated in angle by the prism. 
B)  different colors are caused by multiple reflections in the prism and interference between the resulting beams. 
C)  prism absorbs colors from different parts of the broad beam coming out of the prism, leaving the complementary colors that we see. 
D)  prism adds colors to different parts of the broadly scattered beam coming out of it.

Question 5

The Sun's spectrum peaks in the yellow-green region (i.e.,this region is the most intense part of its spectrum).The spectrum of Rigel (the star in the knee of Rigel)peaks in the short-wavelength end of the visible spectrum.Compared with the Sun,Rigel is:

Accepted Answer

A)  cooler and redder. 
B)  cooler and whiter. 
C)  hotter and redder. 
D)  hotter and whiter. 
A)  cooler and redder. 
B)  cooler and whiter. 
C)  hotter and redder. 
D)  hotter and whiter.

Question 6

After the Hubble Space Telescope was launched,it was found to suffer seriously from:

Accepted Answer

A)  scattering of light from dust on the primary mirror surface. 
B)  too much angular resolution. 
C)  spherical aberration. 
D)  chromatic aberration. 
A)  scattering of light from dust on the primary mirror surface. 
B)  too much angular resolution. 
C)  spherical aberration. 
D)  chromatic aberration.

Question 7

What are the basic parts of a Schmidt-Cassegrain telescope?

Accepted Answer

A)  a spherical, concave primary mirror and a glass corrector plate 
B)  a parabolic, concave primary mirror and a convex secondary mirror 
C)  a parabolic, concave primary mirror and a concave secondary mirror 
D)  a parabolic, concave primary mirror and a flat, diagonal secondary mirror 
A)  a spherical, concave primary mirror and a glass corrector plate 
B)  a parabolic, concave primary mirror and a convex secondary mirror 
C)  a parabolic, concave primary mirror and a concave secondary mirror 
D)  a parabolic, concave primary mirror and a flat, diagonal secondary mirror

Question 8

To a physicist,a blackbody is defined as an object that:

Accepted Answer

A)  always emits the same spectrum of light, whatever its temperature. 
B)  reflects all radiation that falls on it, never heating up and always appearing black. 
C)  always appears to be black, whatever its temperature. 
D)  absorbs all radiation that falls on it. 
A)  always emits the same spectrum of light, whatever its temperature. 
B)  reflects all radiation that falls on it, never heating up and always appearing black. 
C)  always appears to be black, whatever its temperature. 
D)  absorbs all radiation that falls on it.

Question 9

One technique that astronomers are now using to increase the amount of detail that can be recorded with telescopes is:

Accepted Answer

A)  spinning huge tubs of mercury, thus producing very large parabolic surfaces at relatively low cost. 
B)  antireflective coatings, where the mirror is coated with a substance such as calcium fluorite to reduce the amount of reflected light. 
C)  increased size, with mirrors up to 10 m in diameter (far larger than at earlier times), thereby producing greater intrinsic angular resolution. 
D)  adaptive optics, where the tilt and shape of mirrors in the telescope are changed many times per second to compensate for atmospheric turbulence. 
A)  spinning huge tubs of mercury, thus producing very large parabolic surfaces at relatively low cost. 
B)  antireflective coatings, where the mirror is coated with a substance such as calcium fluorite to reduce the amount of reflected light. 
C)  increased size, with mirrors up to 10 m in diameter (far larger than at earlier times), thereby producing greater intrinsic angular resolution. 
D)  adaptive optics, where the tilt and shape of mirrors in the telescope are changed many times per second to compensate for atmospheric turbulence.

Question 10

An astronomer finds a source of light in space that emits light only in specific,narrow emission lines.Kirchhoff's laws lead the astronomer to which conclusion?

Accepted Answer

A)  The source cannot consist of gases but rather must be a solid object. 
B)  The source is made up of a hot, dense gas. 
C)  The source is made up of a hot, low-density gas. 
D)  The source is made up of a hot, dense gas surrounded by a rarefied gas. 
A)  The source cannot consist of gases but rather must be a solid object. 
B)  The source is made up of a hot, dense gas. 
C)  The source is made up of a hot, low-density gas. 
D)  The source is made up of a hot, dense gas surrounded by a rarefied gas.

Question 11

Which of the following points is NOT a characteristic of a prism,compared with a diffraction grating,when used in a spectrograph?

Accepted Answer

A)  A prism causes different light rays to interfere with one another. 
B)  A prism absorbs light unevenly over the spectrum (over the different colors). 
C)  A prism does not pass ultraviolet light. 
D)  A prism spreads the light out unevenly in wavelength. 
A)  A prism causes different light rays to interfere with one another. 
B)  A prism absorbs light unevenly over the spectrum (over the different colors). 
C)  A prism does not pass ultraviolet light. 
D)  A prism spreads the light out unevenly in wavelength.

Question 12

In terms of wavelengths,gamma rays:

Accepted Answer

A)  have the shortest wavelengths of the named electromagnetic waves. 
B)  are intermediate, between X-rays and ultraviolet radiation. 
C)  are intermediate, between radio waves and infrared radiation. 
D)  have the longest wavelengths of the named electromagnetic waves. 
A)  have the shortest wavelengths of the named electromagnetic waves. 
B)  are intermediate, between X-rays and ultraviolet radiation. 
C)  are intermediate, between radio waves and infrared radiation. 
D)  have the longest wavelengths of the named electromagnetic waves.

Question 13

What characteristic of the 10-m Keck telescope makes it fundamentally different from older telescopes,such as the one on Mt.Palomar?

Accepted Answer

A)  It is located in Earth orbit, away from all the distortions of Earth's atmosphere. 
B)  It is actually four closely spaced telescopes that can be operated together, as if they were a single telescope. 
C)  Its primary mirror is a large, very thin piece of glass that can be deformed rapidly to compensate for seeing. 
D)  Its primary mirror is made up of 36 separate mirror segments. 
A)  It is located in Earth orbit, away from all the distortions of Earth's atmosphere. 
B)  It is actually four closely spaced telescopes that can be operated together, as if they were a single telescope. 
C)  Its primary mirror is a large, very thin piece of glass that can be deformed rapidly to compensate for seeing. 
D)  Its primary mirror is made up of 36 separate mirror segments.

Question 14

X-rays and visible light are:

Accepted Answer

A)  different because X-rays are made up of waves, whereas light is made up of particles. 
B)  different because X-rays are made up of particles, whereas light is made up of waves. 
C)  the same thing except that X-rays have longer wavelengths than visible light. 
D)  the same thing except that X-rays have shorter wavelengths than visible light. 
A)  different because X-rays are made up of waves, whereas light is made up of particles. 
B)  different because X-rays are made up of particles, whereas light is made up of waves. 
C)  the same thing except that X-rays have longer wavelengths than visible light. 
D)  the same thing except that X-rays have shorter wavelengths than visible light.

Question 15

How does the speed of light in a substance such as glass compare with the speed of light in a vacuum?

Accepted Answer

A)  The speed of light in glass is faster than the speed of light in a vacuum. 
B)  The speed of light is the same in both, equal to 299,792.458 km/s. 
C)  The speed of light in glass is slower than the speed of light in a vacuum. 
D)  The speed of light in glass can be faster or slower than the speed of light in a vacuum, depending on the type of glass. 
A)  The speed of light in glass is faster than the speed of light in a vacuum. 
B)  The speed of light is the same in both, equal to 299,792.458 km/s. 
C)  The speed of light in glass is slower than the speed of light in a vacuum. 
D)  The speed of light in glass can be faster or slower than the speed of light in a vacuum, depending on the type of glass.

Question 16

The MAIN absorber in the atmosphere for infrared radiation,which impedes observations of astronomical infrared objects,is:

Accepted Answer

A)  water vapor, H₂O. 
B)  nitrogen and oxygen (N₂ and O₂), the major constituents of the atmosphere. 
C)  electrons and ionized atoms in Earth's ionosphere. 
D)  dust. 
A)  water vapor, H₂O. 
B)  nitrogen and oxygen (N₂ and O₂), the major constituents of the atmosphere. 
C)  electrons and ionized atoms in Earth's ionosphere. 
D)  dust.

Question 17

By what factor is the light-gathering power of the 10-m-diameter Keck telescope on Mauna Kea in Hawaii greater than an average unaided human eye,with a typical aperture diameter of 5 mm?

Accepted Answer

A)  2.5 × 10⁵ times 
B)  2 × 10⁴ times 
C)  2000 times 
D)  4 × 10⁶ times 
A)  2.5 × 10⁵ times 
B)  2 × 10⁴ times 
C)  2000 times 
D)  4 × 10⁶ times

Question 18

The speed of light always has the same value in a vacuum:

Accepted Answer

A)  but its speed inside a transparent material depends on the temperature of the material and can be faster or slower than its speed in a vacuum. 
B)  as it does in transparent materials. 
C)  but is slower in transparent materials such as water and glass. 
D)  but is faster in transparent materials such as water and glass. 
A)  but its speed inside a transparent material depends on the temperature of the material and can be faster or slower than its speed in a vacuum. 
B)  as it does in transparent materials. 
C)  but is slower in transparent materials such as water and glass. 
D)  but is faster in transparent materials such as water and glass.

Question 19

Which one of these temperatures is HOTTEST?

Accepted Answer

A)  100 K 
B)  100°C 
C)  100°F 
D)  They are all the same. 
A)  100 K 
B)  100°C 
C)  100°F 
D)  They are all the same.

Question 20

If you send white light through a prism to produce a spectrum,and then send this entire spectrum through a lens to recombine it,the result will be:

Accepted Answer

A)  red. 
B)  yellow. 
C)  white. 
D)  black (no light). 
A)  red. 
B)  yellow. 
C)  white. 
D)  black (no light).

What is a diffraction grating?

What is the relationship between color and wavelength for light?

How is chromatic aberration MOST often corrected in a modern refracting telescope?

When light passes through a prism of glass,the:

The Sun's spectrum peaks in the yellow-green region (i.e.,this region is the most intense part of its spectrum).The spectrum of Rigel (the star in the knee of Rigel)peaks in the short-wavelength end of the visible spectrum.Compared with the Sun,Rigel is:

After the Hubble Space Telescope was launched,it was found to suffer seriously from:

What are the basic parts of a Schmidt-Cassegrain telescope?

To a physicist,a blackbody is defined as an object that:

One technique that astronomers are now using to increase the amount of detail that can be recorded with telescopes is:

An astronomer finds a source of light in space that emits light only in specific,narrow emission lines.Kirchhoff's laws lead the astronomer to which conclusion?

Which of the following points is NOT a characteristic of a prism,compared with a diffraction grating,when used in a spectrograph?

In terms of wavelengths,gamma rays:

What characteristic of the 10-m Keck telescope makes it fundamentally different from older telescopes,such as the one on Mt.Palomar?

X-rays and visible light are:

How does the speed of light in a substance such as glass compare with the speed of light in a vacuum?

The MAIN absorber in the atmosphere for infrared radiation,which impedes observations of astronomical infrared objects,is:

By what factor is the light-gathering power of the 10-m-diameter Keck telescope on Mauna Kea in Hawaii greater than an average unaided human eye,with a typical aperture diameter of 5 mm?

The speed of light always has the same value in a vacuum:

Which one of these temperatures is HOTTEST?

If you send white light through a prism to produce a spectrum,and then send this entire spectrum through a lens to recombine it,the result will be:

Discovering the Night Sky

Gravitation and the Waltz of the Planets

Formation of the Solar System and Other Planetary Systems

Exoplanets

The Terrestrial Planets and Their Moons

The Outer Planets and Their Moons

Vagabonds of the Solar System

The Sun: Our Extraordinary Ordinary Star

Characterizing Stars

The Lives of the Stars From Birth Through Middle Age

The Deaths and Remnants of Stars

The Galaxies

Cosmology

Astrobiology

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Exam 3: Light and Telescopes

What is a diffraction grating?

What is the relationship between color and wavelength for light?

How is chromatic aberration MOST often corrected in a modern refracting telescope?

When light passes through a prism of glass,the:

The Sun's spectrum peaks in the yellow-green region (i.e.,this region is the most intense part of its spectrum).The spectrum of Rigel (the star in the knee of Rigel)peaks in the short-wavelength end of the visible spectrum.Compared with the Sun,Rigel is:

After the Hubble Space Telescope was launched,it was found to suffer seriously from:

What are the basic parts of a Schmidt-Cassegrain telescope?

To a physicist,a blackbody is defined as an object that:

One technique that astronomers are now using to increase the amount of detail that can be recorded with telescopes is:

An astronomer finds a source of light in space that emits light only in specific,narrow emission lines.Kirchhoff's laws lead the astronomer to which conclusion?

Which of the following points is NOT a characteristic of a prism,compared with a diffraction grating,when used in a spectrograph?

In terms of wavelengths,gamma rays:

What characteristic of the 10-m Keck telescope makes it fundamentally different from older telescopes,such as the one on Mt.Palomar?

X-rays and visible light are:

How does the speed of light in a substance such as glass compare with the speed of light in a vacuum?

The MAIN absorber in the atmosphere for infrared radiation,which impedes observations of astronomical infrared objects,is:

By what factor is the light-gathering power of the 10-m-diameter Keck telescope on Mauna Kea in Hawaii greater than an average unaided human eye,with a typical aperture diameter of 5 mm?

The speed of light always has the same value in a vacuum:

Which one of these temperatures is HOTTEST?

If you send white light through a prism to produce a spectrum,and then send this entire spectrum through a lens to recombine it,the result will be:

Discovering the Night Sky

Gravitation and the Waltz of the Planets

Formation of the Solar System and Other Planetary Systems

Exoplanets

The Terrestrial Planets and Their Moons

The Outer Planets and Their Moons

Vagabonds of the Solar System

The Sun: Our Extraordinary Ordinary Star

Characterizing Stars

The Lives of the Stars From Birth Through Middle Age

The Deaths and Remnants of Stars

The Galaxies

Cosmology

Astrobiology

Filters