Question 1

Most modern spectrographs use a _________ to disperse the light from an object.

Accepted Answer

A)  spherical mirror 
B)  lens 
C)  glass prism 
D)  diffraction grating 
E)  parabolic mirror 
A)  spherical mirror 
B)  lens 
C)  glass prism 
D)  diffraction grating 
E)  parabolic mirror D

Question 2

Understanding the results of high-energy collisions between elementary particles can give astronomers insight into conditions that were present during the earliest moments of the universe.

Accepted Answer

A) True 
 B)False  True

Question 3

If we could increase the quantum efficiency of the human eye, it would:

Accepted Answer

A)  allow humans to see a larger range of wavelengths 
B)  allow humans to see better at night, or other low-light conditions 
C)  increase the resolution of the human eye 
D)  decrease the resolution of the human eye 
E)  not make a difference in the sight of the human eye 
A)  allow humans to see a larger range of wavelengths 
B)  allow humans to see better at night, or other low-light conditions 
C)  increase the resolution of the human eye 
D)  decrease the resolution of the human eye 
E)  not make a difference in the sight of the human eye B

Question 4

Why do reflecting telescopes use curved mirrors instead of flat mirrors?

Accepted Answer

The purpose of a telescope is to redirec

Question 5

What property of light allows a grating to disperse the light from an object into a spectrum?

Accepted Answer

A)  interference 
B)  reflection 
C)  refraction 
D)  aberration 
E)  magnification 
A)  interference 
B)  reflection 
C)  refraction 
D)  aberration 
E)  magnification

Question 6

Point sources look brighter when viewed through a telescope.

Accepted Answer

A) True 
 B)False

Question 7

The two Keck 10-m telescopes, separated by a distance of 85 m, can operate as an optical interferometer. What is its resolution when it observes in the infrared at a wavelength of 2 microns?

Accepted Answer

A)  0.01 arcsec 
B)  0.005 arcsec 
C)  0.4 arsec 
D)  0.06 arcsec 
E)  0.2 arcsec 
A)  0.01 arcsec 
B)  0.005 arcsec 
C)  0.4 arsec 
D)  0.06 arcsec 
E)  0.2 arcsec

Question 8

The highest spatial resolution images that we have of many planets' surfaces were obtained with the Hubble Space Telescope.

Accepted Answer

A) True 
 B)False

Question 9

Which of the following phenomena is shown in the figure below?

Accepted Answer

A)  reflection 
B)  refraction 
C)  magnification 
D)  diffraction 
E)  interference 
A)  reflection 
B)  refraction 
C)  magnification 
D)  diffraction 
E)  interference

Question 10

As a beam of light travels from one medium to another, the change in direction of the beam of light depends on:

Accepted Answer

A)  the wavelength of the light 
B)  the index of refraction of the outgoing medium 
C)  the index of refraction of the incoming medium 
D)  the angle of incidence 
E)  all of the above 
A)  the wavelength of the light 
B)  the index of refraction of the outgoing medium 
C)  the index of refraction of the incoming medium 
D)  the angle of incidence 
E)  all of the above

Question 11

The SETI project's Allen Telescope Array will have 350 radio dishes, each with an individual diameter of 6 m, spread out over a circle whose diameter is 1 km. What would this array's spatial resolution be when it operates at 6,000 MHz?

Accepted Answer

A)  10 arcsec 
B)  0.10 arcsec 
C)  1 arcsec 
D)  10 arcmin 
E)  1.0 arcmin 
A)  10 arcsec 
B)  0.10 arcsec 
C)  1 arcsec 
D)  10 arcmin 
E)  1.0 arcmin

Question 12

The aperture of a telescope partially or totally determines its:

Accepted Answer

A)  focal length and magnification 
B)  light-gathering power 
C)  focal length 
D)  light-gathering power and magnification 
E)  light-gathering power and diffraction limit 
A)  focal length and magnification 
B)  light-gathering power 
C)  focal length 
D)  light-gathering power and magnification 
E)  light-gathering power and diffraction limit

Question 13

The magnification of a telescope depends on the focal length of the telescope and:

Accepted Answer

A)  the size of the aperture 
B)  the type of telescope (refracting vs. reflecting) 
C)  the wavelengths being observed 
D)  the focal length of the eyepiece 
E)  the angular resolution of the telescope 
A)  the size of the aperture 
B)  the type of telescope (refracting vs. reflecting) 
C)  the wavelengths being observed 
D)  the focal length of the eyepiece 
E)  the angular resolution of the telescope

Question 14

You are observing the Andromeda Galaxy using both photographic plates and a CCD. If you double the exposure time for both detectors, you:

Accepted Answer

A)  double the amount of light collected on both the photographic plate and the CCD 
B)  double the amount of light collected on the CCD, but the photographic plate collects less 
C)  double the amount of light collected on the photographic plate, but the CCD collects less 
D)  double the amount of light collected on the photographic plate, but the CCD collects more 
E)  collect less than twice the amount of light on both the photographic plate and the CCD 
A)  double the amount of light collected on both the photographic plate and the CCD 
B)  double the amount of light collected on the CCD, but the photographic plate collects less 
C)  double the amount of light collected on the photographic plate, but the CCD collects less 
D)  double the amount of light collected on the photographic plate, but the CCD collects more 
E)  collect less than twice the amount of light on both the photographic plate and the CCD

Question 15

Ultraviolet radiation is hard to observe primarily because:

Accepted Answer

A)  the Earth's atmosphere easily absorbs it 
B)  no space-based telescopes operate at ultraviolet wavelengths 
C)  only the lowest mass stars emit ultraviolet light 
D)  very few objects emit at ultraviolet wavelengths 
E)  the Earth emits too much ultraviolet background light 
A)  the Earth's atmosphere easily absorbs it 
B)  no space-based telescopes operate at ultraviolet wavelengths 
C)  only the lowest mass stars emit ultraviolet light 
D)  very few objects emit at ultraviolet wavelengths 
E)  the Earth emits too much ultraviolet background light

Question 16

An object sits at the focal point of a parabolic mirror. At what distance from the mirror will its image be created?

Accepted Answer

A)  It will be imaged at half the focal length. 
B)  It will be imaged at the focal length. 
C)  It will be imaged at twice the focal length. 
D)  No image will be created (the beams would be reflected parallel to each other). 
E)  The image is created on the other side of the mirror. 
A)  It will be imaged at half the focal length. 
B)  It will be imaged at the focal length. 
C)  It will be imaged at twice the focal length. 
D)  No image will be created (the beams would be reflected parallel to each other). 
E)  The image is created on the other side of the mirror.

Question 17

Telescopes and satellites such as COBE, WMAP, and Planck are designed to detect microwave radiation emitted by:

Accepted Answer

A)  galaxies 
B)  black holes 
C)  planets 
D)  the Big Bang 
E)  stars 
A)  galaxies 
B)  black holes 
C)  planets 
D)  the Big Bang 
E)  stars

Question 18

Arrays of radio telescopes can produce much better resolution than single-dish telescopes because they work based on the principle of:

Accepted Answer

A)  reflection 
B)  refraction 
C)  dispersion 
D)  diffraction 
E)  interference 
A)  reflection 
B)  refraction 
C)  dispersion 
D)  diffraction 
E)  interference

Question 19

Where is the best place to put a ground-based optical telescope? Discuss the reasons for your selection.

Accepted Answer

Mountaintops away from cities and in dry

Question 20

When we determine the angular resolution of an interferometric array of radio telescopes using the formula $\theta$ $\infty$ $\lambda$/D, the variable D stands for the:

Accepted Answer

A)  diameter of the telescopes 
B)  separation between the telescopes 
C)  magnification of the telescopes 
D)  number of telescopes 
E)  focal length of the telescopes 
A)  diameter of the telescopes 
B)  separation between the telescopes 
C)  magnification of the telescopes 
D)  number of telescopes 
E)  focal length of the telescopes

Exam 6: The Tools of the Astronomer

Most modern spectrographs use a _________ to disperse the light from an object.

Understanding the results of high-energy collisions between elementary particles can give astronomers insight into conditions that were present during the earliest moments of the universe.

If we could increase the quantum efficiency of the human eye, it would:

Why do reflecting telescopes use curved mirrors instead of flat mirrors?

What property of light allows a grating to disperse the light from an object into a spectrum?

Point sources look brighter when viewed through a telescope.

The two Keck 10-m telescopes, separated by a distance of 85 m, can operate as an optical interferometer. What is its resolution when it observes in the infrared at a wavelength of 2 microns?

The highest spatial resolution images that we have of many planets' surfaces were obtained with the Hubble Space Telescope.

Which of the following phenomena is shown in the figure below?

As a beam of light travels from one medium to another, the change in direction of the beam of light depends on:

The SETI project's Allen Telescope Array will have 350 radio dishes, each with an individual diameter of 6 m, spread out over a circle whose diameter is 1 km. What would this array's spatial resolution be when it operates at 6,000 MHz?

The aperture of a telescope partially or totally determines its:

The magnification of a telescope depends on the focal length of the telescope and:

You are observing the Andromeda Galaxy using both photographic plates and a CCD. If you double the exposure time for both detectors, you:

Ultraviolet radiation is hard to observe primarily because:

An object sits at the focal point of a parabolic mirror. At what distance from the mirror will its image be created?

Telescopes and satellites such as COBE, WMAP, and Planck are designed to detect microwave radiation emitted by:

Arrays of radio telescopes can produce much better resolution than single-dish telescopes because they work based on the principle of:

Where is the best place to put a ground-based optical telescope? Discuss the reasons for your selection.

When we determine the angular resolution of an interferometric array of radio telescopes using the formula θ\thetaθ ∞\infty∞ λ\lambdaλ /D, the variable D stands for the:

Why Learn Astronomy

Patterns in the Skymotions of Earth

Motion of Astronomical Bodies

Gravity and Orbits

Light

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

Relativity and Black Holes

The Expanding Universe

Galaxies

The Milky Waya Normal Spiral Galaxy

Modern Cosmology

Large-Scale Structure in the Universe

Life

Filters

When we determine the angular resolution of an interferometric array of radio telescopes using the formula $\theta$ $\infty$ $\lambda$ /D, the variable D stands for the: