Question 1

The major cause of blurred and unsharp images of objects observed through very large telescopes at the extreme limit of magnification is the

Accepted Answer

A)  poor tracking capabilities of modern telescopes. 
B)  poor optical polish achievable on large mirrors. 
C)  clumsiness of the telescope operator. 
D)  air turbulence in Earth's atmosphere. 
A)  poor tracking capabilities of modern telescopes. 
B)  poor optical polish achievable on large mirrors. 
C)  clumsiness of the telescope operator. 
D)  air turbulence in Earth's atmosphere.

Question 2

A Cassegrain telescope has a primary mirror with a 5-m diameter and a hole of diameter 5 cm through the primary mirror. By what percent is the light-gathering power of the mirror reduced because of the hole?

Accepted Answer

A)  0.01% 
B)  1% 
C)  20% 
D)  50% 
A)  0.01% 
B)  1% 
C)  20% 
D)  50%

Question 3

Refraction is the

Accepted Answer

A)  bending of light as it enters a dense but transparent material at an angle to the perpendicular to the surface of the material. 
B)  bending of light around the sharp edge of an obstacle. 
C)  change in direction of light when it bounces off a smooth surface. 
D)  change in the color of light when it enters a transparent but colored material, such as glass. 
A)  bending of light as it enters a dense but transparent material at an angle to the perpendicular to the surface of the material. 
B)  bending of light around the sharp edge of an obstacle. 
C)  change in direction of light when it bounces off a smooth surface. 
D)  change in the color of light when it enters a transparent but colored material, such as glass.

Question 4

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 5

Electromagnetic radiation emitted by a planet has a wavelength of 10 micrometers (1 m = 10-6 m). What name is given to this type of electromagnetic radiation?

Accepted Answer

A)  gamma ray 
B)  infrared 
C)  radio 
D)  visible light 
A)  gamma ray 
B)  infrared 
C)  radio 
D)  visible light

Question 6

How does the angular resolution of the 305-m Arecibo telescope in Puerto Rico, which observes radio waves, compare with the angular resolution of the 10-m Keck telescope on Mauna Kea, Hawaii, which observes optical light? Assume each telescope observes the light they were designed to see.

Accepted Answer

A)  It is not possible to compare their angular resolution because they work in different wavelength ranges. 
B)  The 305-m Arecibo telescope has much better angular resolution than the 10-m Keck telescope. 
C)  They have about the same angular resolution because angular resolution is limited by turbulence in Earth's atmosphere, not by mirror diameter. 
D)  The 305-m Arecibo telescope has much worse angular resolution than the 10-m Keck telescope. 
A)  It is not possible to compare their angular resolution because they work in different wavelength ranges. 
B)  The 305-m Arecibo telescope has much better angular resolution than the 10-m Keck telescope. 
C)  They have about the same angular resolution because angular resolution is limited by turbulence in Earth's atmosphere, not by mirror diameter. 
D)  The 305-m Arecibo telescope has much worse angular resolution than the 10-m Keck telescope.

Question 7

A refracting telescope has an objective lens of focal length 40 cm and a diameter of 10 cm, and an eyepiece of focal length 5 cm and diameter 1 cm. What is the magnifying power of this telescope?

Accepted Answer

A)  10× 
B)  40× 
C)  2× 
D)  8× 
A)  10× 
B)  40× 
C)  2× 
D)  8×

Question 8

Astronomers sometimes choose the type of reflecting telescope to use as a result of the amount of strain the weight of the mounted equipment will exert on the telescope. Which type of reflector generally results in the MOST strain?

Accepted Answer

A)  Cassegrain focus 
B)  Newtonian focus 
C)  prime focus 
D)  coudé focus 
A)  Cassegrain focus 
B)  Newtonian focus 
C)  prime focus 
D)  coudé focus

Question 9

When light passes from air into a dense but transparent material such as glass, it

Accepted Answer

A)  slows down. 
B)  maintains its speed, as required by the laws of physics. 
C)  changes its speed to that of sound in the medium. 
D)  speeds up. 
A)  slows down. 
B)  maintains its speed, as required by the laws of physics. 
C)  changes its speed to that of sound in the medium. 
D)  speeds up.

Question 10

Which statement about the twinkling of stars and planets is NOT correct?

Accepted Answer

A)  Stars twinkle less when they are farther from the horizon. 
B)  A photographic image of more than a few seconds exposure time will show a twinkling star as a disk. 
C)  Planets twinkle less than stars. 
D)  Twinkling of stars is an inherent phenomenon and cannot be reduced by any observing technique. 
A)  Stars twinkle less when they are farther from the horizon. 
B)  A photographic image of more than a few seconds exposure time will show a twinkling star as a disk. 
C)  Planets twinkle less than stars. 
D)  Twinkling of stars is an inherent phenomenon and cannot be reduced by any observing technique.

Question 11

Who first showed that light does not travel at infinite speed, and when did they show it?

Accepted Answer

A)  Ole Rømer in 1675 
B)  Thomas Young in 1801 
C)  James Clerk Maxwell in 1864 
D)  Isaac Newton in 1704 
A)  Ole Rømer in 1675 
B)  Thomas Young in 1801 
C)  James Clerk Maxwell in 1864 
D)  Isaac Newton in 1704

Question 12

Which of these statements is true?

Accepted Answer

A)  Visible light takes up only a very small part of the total range of wavelengths in the electromagnetic spectrum. 
B)  Visible light takes up the whole electromagnetic spectrum. 
C)  Visible light takes up most (but not all) of the total range of wavelengths in the electromagnetic spectrum. 
D)  Visible light is not part of the electromagnetic spectrum. 
A)  Visible light takes up only a very small part of the total range of wavelengths in the electromagnetic spectrum. 
B)  Visible light takes up the whole electromagnetic spectrum. 
C)  Visible light takes up most (but not all) of the total range of wavelengths in the electromagnetic spectrum. 
D)  Visible light is not part of the electromagnetic spectrum.

Question 13

It is now understood that there are three "flavors" of neutrinos. These do NOT include the

Accepted Answer

A)  electron neutrino. 
B)  proton neutrino. 
C)  tau neutrino. 
D)  muon neutrino. 
A)  electron neutrino. 
B)  proton neutrino. 
C)  tau neutrino. 
D)  muon neutrino.

Question 14

Which of these statements describing a disadvantage of large refracting telescopes when compared to large reflecting telescopes is NOT correct?

Accepted Answer

A)  Sagging of the primary optical element under its own weight is a problem with refracting telescopes but not with reflecting telescopes. 
B)  Refracting telescopes suffer from chromatic aberration, whereas reflecting telescopes do not. 
C)  Refracting telescopes can suffer from spherical aberration, whereas reflecting telescopes cannot. 
D)  Air bubbles in the glass are more of a problem in refracting telescopes than in reflecting telescopes. 
A)  Sagging of the primary optical element under its own weight is a problem with refracting telescopes but not with reflecting telescopes. 
B)  Refracting telescopes suffer from chromatic aberration, whereas reflecting telescopes do not. 
C)  Refracting telescopes can suffer from spherical aberration, whereas reflecting telescopes cannot. 
D)  Air bubbles in the glass are more of a problem in refracting telescopes than in reflecting telescopes.

Question 15

How have astrophysicists detected gravitational waves?

Accepted Answer

A)  Large underground water tanks show flashes of light when gravitational waves interact with their constituent particles. 
B)  Lasers measure tiny changes in distances as gravitational waves pass. 
C)  They detect showers of particles when the gravitational waves interact with Earth's atmosphere. 
D)  Gravitational waves have not yet been detected 
A)  Large underground water tanks show flashes of light when gravitational waves interact with their constituent particles. 
B)  Lasers measure tiny changes in distances as gravitational waves pass. 
C)  They detect showers of particles when the gravitational waves interact with Earth's atmosphere. 
D)  Gravitational waves have not yet been detected

The major cause of blurred and unsharp images of objects observed through very large telescopes at the extreme limit of magnification is the

A Cassegrain telescope has a primary mirror with a 5-m diameter and a hole of diameter 5 cm through the primary mirror. By what percent is the light-gathering power of the mirror reduced because of the hole?

Refraction is the

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

Electromagnetic radiation emitted by a planet has a wavelength of 10 micrometers (1 m = 10^-6 m). What name is given to this type of electromagnetic radiation?

How does the angular resolution of the 305-m Arecibo telescope in Puerto Rico, which observes radio waves, compare with the angular resolution of the 10-m Keck telescope on Mauna Kea, Hawaii, which observes optical light? Assume each telescope observes the light they were designed to see.

A refracting telescope has an objective lens of focal length 40 cm and a diameter of 10 cm, and an eyepiece of focal length 5 cm and diameter 1 cm. What is the magnifying power of this telescope?

Astronomers sometimes choose the type of reflecting telescope to use as a result of the amount of strain the weight of the mounted equipment will exert on the telescope. Which type of reflector generally results in the MOST strain?

When light passes from air into a dense but transparent material such as glass, it

Which statement about the twinkling of stars and planets is NOT correct?

Who first showed that light does not travel at infinite speed, and when did they show it?

Which of these statements is true?

It is now understood that there are three "flavors" of neutrinos. These do NOT include the

Which of these statements describing a disadvantage of large refracting telescopes when compared to large reflecting telescopes is NOT correct?

How have astrophysicists detected gravitational waves?

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 major cause of blurred and unsharp images of objects observed through very large telescopes at the extreme limit of magnification is the

A Cassegrain telescope has a primary mirror with a 5-m diameter and a hole of diameter 5 cm through the primary mirror. By what percent is the light-gathering power of the mirror reduced because of the hole?

Refraction is the

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

Electromagnetic radiation emitted by a planet has a wavelength of 10 micrometers (1 m = 10-6 m). What name is given to this type of electromagnetic radiation?

How does the angular resolution of the 305-m Arecibo telescope in Puerto Rico, which observes radio waves, compare with the angular resolution of the 10-m Keck telescope on Mauna Kea, Hawaii, which observes optical light? Assume each telescope observes the light they were designed to see.

A refracting telescope has an objective lens of focal length 40 cm and a diameter of 10 cm, and an eyepiece of focal length 5 cm and diameter 1 cm. What is the magnifying power of this telescope?

Astronomers sometimes choose the type of reflecting telescope to use as a result of the amount of strain the weight of the mounted equipment will exert on the telescope. Which type of reflector generally results in the MOST strain?

When light passes from air into a dense but transparent material such as glass, it

Which statement about the twinkling of stars and planets is NOT correct?

Who first showed that light does not travel at infinite speed, and when did they show it?

Which of these statements is true?

It is now understood that there are three "flavors" of neutrinos. These do NOT include the

Which of these statements describing a disadvantage of large refracting telescopes when compared to large reflecting telescopes is NOT correct?

How have astrophysicists detected gravitational waves?

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

Electromagnetic radiation emitted by a planet has a wavelength of 10 micrometers (1 m = 10^-6 m). What name is given to this type of electromagnetic radiation?