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Telescopes
Review
Using ___________, scientists can use a few
smaller telescopes to take images with the same
resolution as a much larger telescope.
A. Satellite telescopes
B. Charge-coupled devices (CCDs)
C. Interferometry
D. Adaptive optics
Using ___________, scientists can use a few
smaller telescopes to take images with the same
resolution as a much larger telescope.
A. Satellite telescopes
B. Charge-coupled devices (CCDs)
C. Interferometry
D. Adaptive optics
A warm dust cloud in which stars are forming
would be best observed with a(n) _________
telescope.
A. Radio
B. Gamma-Ray
C. Infrared
D. Optical (visible light)
A warm dust cloud in which stars are forming
would be best observed with a(n) _________
telescope.
A. Radio
B. Gamma-Ray
C. Infrared
D. Optical (visible light)
In a false color image,
A. Only one color is used.
B. Color information from optical telescopes is
combined with information from a non-visible
wavelength telescope to make the image.
C. Stars appear black and the background
appears white.
D. Colors can represent photon energies or the
intensity of electromagnetic radiation.
In a false color image,
A. Only one color is used.
B. Color information from optical telescopes is
combined with information from a non-visible
wavelength telescope to make the image.
C. Stars appear black and the background
appears white.
D. Colors can represent photon energies or the
intensity of electromagnetic radiation.
If your pupils have a diameter of about 5mm, about
how many times more light gathering power does a
telescope with a diameter of about 20 cm (8 inches)
have than your pupils?
A. 4 times
B. 16 times
C. 40 times
D. 160 times
E. 1600 times
If your pupils have a diameter of about 5mm,
about how many times more light gathering
power does a telescope with a diameter of
about 20 cm (8 inches) have than your pupils?
A. 4 times
B. 16 times
C. 40 times
D. 160 times
E. 1600 times
One of the biggest problems for ground based
astronomy today is
A. All the best mountains already have telescopes
on them.
B. Atmospheric pollution has significantly worsened
the seeing.
C. Space-based observatories are making most of
the observations.
D. Light pollution makes it difficult to observe faint
objects.
One of the biggest problems for ground based
astronomy today is
A. All the best mountains already have telescopes
on them.
B. Atmospheric pollution has significantly worsened
the seeing.
C. Space-based observatories are making most of
the observations.
D. Light pollution makes it difficult to observe faint
objects.
. A pencil inside a water glass appears to be bent
because of
A. Reflection of light.
B. Refraction of light.
C. Diffraction of light.
D. None of the above.
A pencil inside a water glass appears to be bent
because of
A. Reflection of light.
B. Refraction of light.
C. Diffraction of light.
D. None of the above.
Why does the Moon appear bigger near the
horizon?
A. Due to an optical illusion.
B. Due to refraction.
C. Due to reflection.
D. Due to the compression produced by the
Earth's atmosphere.
Why does the Moon appear bigger near the
horizon?
A. Due to an optical illusion.
B. Due to refraction.
C. Due to reflection.
D. Due to the compression produced by the
Earth's atmosphere.
The ability of a telescope to show two very close
objects separately is called its ________.
A. Light gathering power
B. Resolving power
C. Magnification
D. None of the above
The ability of a telescope to show two very close
objects separately is called its ________.
A. Light gathering power
B. Resolving power
C. Magnification
D. None of the above
Tom has a 4-inch refracting telescope and Steve has
a 3-inch reflecting telescope. Whose telescope has
a higher resolving power?
A. Tom's, because lenses are more efficient in
showing the objects separately.
B. Steve's, because mirrors are more efficient in
showing the objects separately.
C. Tom's, because the larger the diameter, the
better the resolution.
D. Steve's, because the smaller the diameter, the
better the resolution.
Tom has a 4-inch refracting telescope and Steve has
a 3-inch reflecting telescope. Whose telescope has
a higher resolving power?
A. Tom's, because lenses are more efficient in
showing the objects separately.
B. Steve's, because mirrors are more efficient in
showing the objects separately.
C. Tom's, because the larger the diameter, the
better the resolution.
D. Steve's, because the smaller the diameter, the
better the resolution.
The best site for placing an X-ray telescope is
_________.
A. A mountain top
B. A valley
C. Near an ocean
D. A desert
E. Above the Earth's atmosphere
The best site for placing an X-ray telescope is
_________.
A. A mountain top
B. A valley
C. Near an ocean
D. A desert
E. Above the Earth's atmosphere
An interstellar gas is emitting 10-centimeter
wavelength radiation and a nearby star is
emitting 10-micrometer wavelength radiation.
Which of these can you observe through an
Earth-based telescope?
A. The interstellar gas
B. The star
C. Both of them
D. Neither of them
An interstellar gas is emitting 10-centimeter
wavelength radiation and a nearby star is
emitting 10-micrometer wavelength radiation.
Which of these can you observe through an
Earth-based telescope?
A. The interstellar gas
B. The star
C. Both of them
D. Neither of them
Why do stars twinkle?
A. Due to rapid changes occurring on their
surfaces.
B. Due to their movement across the sky.
C. Due to the refraction caused by atmospheric
irregularities.
D. Due to imperfections in the human eye.
Why do stars twinkle?
A. Due to rapid changes occurring on their
surfaces.
B. Due to their movement across the sky.
C. Due to the refraction caused by atmospheric
irregularities.
D. Due to imperfections in the human eye.
Which space telescope is observing X-rays?
A. The Hubble Space Telescope (HST)
B. The Chandra Observatory
C. The Spitzer Space Telescope
D. The Extreme Ultraviolet Explorer (EUVE)
Which space telescope is observing X-rays?
A. The Hubble Space Telescope (HST)
B. The Chandra Observatory
C. The Spitzer Space Telescope
D. The Extreme Ultraviolet Explorer (EUVE)
Which of the following telescopes is most
suitable for observing cool gas clouds?
A. X-ray telescope.
B. Radio telescope.
C. Visible light telescope.
D. All of the above.
E. Cool gas clouds cannot be observed by
telescopes.
Which of the following telescopes is most
suitable for observing cool gas clouds?
A. X-ray telescope.
B. Radio telescope.
C. Visible light telescope.
D. All of the above.
E. Cool gas clouds cannot be observed by
telescopes.
If a 3 meter diameter telescope is doubled in
size, then its new light collecting power would
A. Not change.
B. Double.
C. Increase by a factor of four.
D. Reduce by half.
If a 3 meter diameter telescope is doubled in
size, then its new light collecting power would
A. Not change.
B. Double.
C. Increase by a factor of four.
D. Reduce by half.
______ is the most important quality of an
astronomical telescope.
A. Magnification
B. Resolving power
C. Ability to see at night
D. Rigidity
______ is the most important quality of an
astronomical telescope.
A. Magnification
B. Resolving power
C. Ability to see at night
D. Rigidity
Which of the following is an inherent disadvantage
of radio telescopes?
A. Radio telescopes cannot detect visible light.
B. Radio telescopes have low magnification.
C. Radio signals are very weak, and their photons
do not penetrate the atmosphere easily.
D. The long wavelength of radio waves results in
lower resolving power, compared to other
telescopes of the same size.
E. They only work at night.
Which of the following is an inherent disadvantage
of radio telescopes?
A. Radio telescopes cannot detect visible light.
B. Radio telescopes have low magnification.
C. Radio signals are very weak, and their photons
do not penetrate the atmosphere easily.
D. The long wavelength of radio waves results in
lower resolving power, compared to other
telescopes of the same size.
E. They only work at night.
Which is the most efficient means of recording
light?
A. Photographic films
B. Photomultiplier tubes
C. Charge-coupled device (CCD)
D. The human eye
Which is the most efficient means of recording
light?
A. Photographic films
B. Photomultiplier tubes
C. Charge-coupled device (CCD)
D. The human eye
X-rays are blocked by ________ and _________
present in the Earth's atmosphere.
A. Water molecules; carbon dioxide
B. Ozone; oxygen
C. Nitrogen; helium
D. Electric charges; clouds
X-rays are blocked by ________ and _________
present in the Earth's atmosphere.
A. Water molecules; carbon dioxide
B. Ozone; oxygen
C. Nitrogen; helium
D. Electric charges; clouds
The best site for placing a ground-based optical
telescope is _________.
A. A mountain top
B. A valley
C. In an urban setting
D. in a location that has few sunny days
throughout the year.
The best site for placing a ground-based optical
telescope is _________.
A. A mountain top
B. A valley
C. In an urban setting
D. in a location that has few sunny days
throughout the year.
What is "seeing"?
A. The ability of a telescope to show two very
close objects separately.
B. The capacity of a telescope to gather more
light.
C. The ability of a telescope to see in the night.
D. The distortion of an image due to an
atmospheric turbulence.
What is "seeing"?
A. The ability of a telescope to show two very
close objects separately.
B. The capacity of a telescope to gather more
light.
C. The ability of a telescope to see in the night.
D. The distortion of an image due to an
atmospheric turbulence.
Carl has a 5-inch refracting telescope and Jim
has a 3-inch reflecting telescope. Whose
telescope has a higher light-gathering power?
A. Carl's, because lenses gather more light.
B. Jim's, because mirrors gather more light.
C. Carl's, because the larger the diameter, the
more light to be collected.
D. Jim's, because the smaller the diameter, the
more light to be collected.
Carl has a 5-inch refracting telescope and Jim
has a 3-inch reflecting telescope. Whose
telescope has a higher light-gathering power?
A. Carl's, because lenses gather more light.
B. Jim's, because mirrors gather more light.
C. Carl's, because the larger the diameter, the
more light to be collected.
D. Jim's, because the smaller the diameter, the
more light to be collected.
What is a disadvantage of using a single, large lens in a
telescope?
A. Large lenses are expensive to fabricate.
B. A lens has to be supported only at its edges, so the lens
can sag in the middle.
C. Different colors of white light on passing through a lens
focus at different points and result in a blurred image.
D. Some lens materials completely absorb short
wavelengths.
E. All of the above.
What is a disadvantage of using a single, large lens
in a telescope?
A. Large lenses are expensive to fabricate.
B. A lens has to be supported only at its edges, so
the lens can sag in the middle.
C. Different colors of white light on passing through
a lens focus at different points and result in a
blurred image.
D. Some lens materials completely absorb short
wavelengths.
E. All of the above.
Why does the Sun look flattened near the horizon?
A. The Sun's light is reflected off the horizon,
making the Sun appear compressed.
B. The Earth's dense atmosphere compresses the
gaseous Sun.
C. The larger refraction near the horizon lifts the
lower edge of the Sun more than the upper edge
and makes the Sun look flattened.
D. The Sun is cooler on the horizon, so it looks
flattened.
Why does the Sun look flattened near the horizon?
A. The Sun's light is reflected off the horizon,
making the Sun appear compressed.
B. The Earth's dense atmosphere compresses the
gaseous Sun.
C. The larger refraction near the horizon lifts the
lower edge of the Sun more than the upper edge
and makes the Sun look flattened.
D. The Sun is cooler on the horizon, so it looks
flattened.
The two most important properties of any
telescope are
A. The light gathering power and the length of the
tube.
B. The length of the tube and the magnification.
C. The magnification and the light gathering power.
D. The resolving power and the magnification.
E. The light gathering power and the resolving
power.
The two most important properties of any
telescope are
A. The light gathering power and the length of
the tube.
B. The length of the tube and the magnification.
C. The magnification and the light gathering
power.
D. The resolving power and the magnification.
E. The light gathering power and the resolving
power.
The resolving power of a telescope is affected by
the property of light called
A. Refraction.
B. Diffraction.
C. Reflection.
D. Seeing.
E. Attenuation.
The resolving power of a telescope is affected by
the property of light called
A. Refraction.
B. Diffraction.
C. Reflection.
D. Seeing.
E. Attenuation.
Ignoring the effects of the atmosphere, what is
the theoretical resolution of an 8 inch telescope
(about 20 cm) if you are looking at visible light
with a wavelength of about 500 nm?
A. About half an arcsecond.
B. About half a degree.
C. About 1/100 of an arcsecond.
D. About 25 arcseconds.
Ignoring the effects of the atmosphere, what is
the theoretical resolution of an 8 inch telescope
(about 20 cm) if you are looking at visible light
with a wavelength of about 500 nm?
A. About half an arcsecond.
B. About half a degree.
C. About 1/100 of an arcsecond.
D. About 25 arcseconds.
A galaxy with almost no starlight but plenty of
cool clouds of hydrogen gas would be best
observed with a(n) _________ telescope.
A. X-ray
B. Radio
C. Infrared
D. Optical (visible light)
A galaxy with almost no starlight but plenty of
cool clouds of hydrogen gas would be best
observed with a(n) _________ telescope.
A. X-ray
B. Radio
C. Infrared
D. Optical (visible light)
To double the resolving power of a telescope,
you must _________.
A. Increase the diameter by a factor of two
B. Increase the collecting area by a factor of two
C. Decrease the diameter by half
D. Decrease the collecting area by half
To double the resolving power of a telescope,
you must _________.
A. Increase the diameter by a factor of two
B. Increase the collecting area by a factor of two
C. Decrease the diameter by half
D. Decrease the collecting area by half
T or F
An optical telescope is able to resolve blue
objects better than red objects.
T or F
An optical telescope is able to resolve blue
objects better than red objects.
T or F
Gamma ray telescopes, such as the Fermi
Gamma Ray Space Telescope, are launched into
space because they are dangerous to operate on
Earth.
T or F
Gamma ray telescopes, such as the Fermi
Gamma Ray Space Telescope, are launched into
space because they are dangerous to operate on
Earth.
T or F
To double the light gathering power of a
telescope, we need to double the diameter.
T or F
To double the light gathering power of a
telescope, we need to double the diameter.
T or F
Most of the modern large optical telescopes are
refractors.
T or F
Most of the modern large optical telescopes are
refractors.
T or F
In a reflecting telescope, the secondary mirror
causes a hole in the center of the image.
T or F
In a reflecting telescope, the secondary mirror
causes a hole in the center of the image.
How do astronomers calculate a telescope's light
collecting area (A)? (where r = radius of the
telescopes mirror or lens, and B is "pi" or 3.14159)
A)
A = 2Br
B)
A = Br2
C)
A = 4Br2
D) A = 4/3 Br3
How do astronomers calculate a telescope's light
collecting area (A)? (where r = radius of the
telescopes mirror or lens, and B is "pi" or 3.14159)
A)
A = 2Br
B)
A = Br2
C)
A = 4Br2
D) A = 4/3 Br3
Telescope A has a mirror twice the diameter of
telescope B's mirror. How does A's lightgathering power compare to B's?
A) A gathers 1/2 the light that B does.
B) A gathers twice the light that B does.
C) A gathers 4 times the light that B
does.
D) A gathers 1/4th as much light as B
does.
Telescope A has a mirror twice the diameter of
telescope B's mirror. How does A's lightgathering power compare to B's?
A) A gathers 1/2 the light that B does.
B) A gathers twice the light that B does.
C) A gathers 4 times the light that B
does.
D) A gathers 1/4th as much light as B
does.
A telescope's resolving power measures its
ability to see
A) fainter sources.
B) more distant sources.
C) finer details in sources.
D) larger sources.
A telescope's resolving power measures its
ability to see
A) fainter sources.
B) more distant sources.
C) finer details in sources.
D) larger sources.
One way to increase the resolving power of a
telescope is to
A) make its mirror bigger.
B) make its mirror smaller.
C) replace its mirror with a lens of the
same diameter.
D) observe objects using longer
wavelengths.
One way to increase the resolving power of a
telescope is to
A) make its mirror bigger.
B) make its mirror smaller.
C) replace its mirror with a lens of the
same diameter.
D) observe objects using longer
wavelengths.
What causes the image of a star to "twinkle" or
scintillate?
A)
irregularities in the density of layers of
Earth's atmosphere, rapidly refracting
the light.
B)
the flickering fusion process in the stars.
C)
a purely physiological reaction in the
eye.
D) none of these answers are correct.
What causes the image of a star to "twinkle" or
scintillate?
A)
irregularities in the density of layers of
Earth's atmosphere, rapidly refracting
the light.
B)
the flickering fusion process in the stars.
C)
a purely physiological reaction in the
eye.
D) none of these answers are correct.
What process limits a telescope's resolving
power?
A) Reflection
B) Refraction
C) Diffraction
D) Distraction
What process limits a telescope's resolving
power?
A) Reflection
B) Refraction
C) Diffraction
D) Distraction
What is the difference between a reflecting and a
refracting telescope?
A)
A reflecting telescope uses a lens to
focus light; a refracting telescope uses a
mirror.
B)
A reflecting telescope uses a mirror to focus
light; a refracting telescope uses a lens.
C)
Both use a mirror to focus light, but a
reflecting telescope uses mirrors elsewhere
to bend light.
D)
There is no difference. "Refracting" is an
outmoded way of saying "reflecting."
What is the difference between a reflecting and a
refracting telescope?
A)
A reflecting telescope uses a lens to
focus light; a refracting telescope uses a
mirror.
B)
A reflecting telescope uses a mirror to focus
light; a refracting telescope uses a lens.
C)
Both use a mirror to focus light, but a
reflecting telescope uses mirrors elsewhere
to bend light.
D)
There is no difference. "Refracting" is an
outmoded way of saying "reflecting."
Light travels __ in water than in air
A) faster
B) slower
C) at the same speed
D) perpendicular to
Light travels __ in water than in air
A) faster
B) slower
C) at the same speed
D) perpendicular to
Which of the these is a reason for using mirrors rather
than lenses in telescopes?
A)
Lenses are more expensive to make than
mirrors.
B)
Most transparent materials focus light of
different colors to different spots.
C)
Lenses can only be supported by their
edges, making them sag in the middle
(mirrors can be supported from behind).
D)
All of the above.
Which of the these is a reason for using mirrors rather
than lenses in telescopes?
A)
Lenses are more expensive to make than
mirrors.
B)
Most transparent materials focus light of
different colors to different spots.
C)
Lenses can only be supported by their
edges, making them sag in the middle
(mirrors can be supported from behind).
D)
All of the above.
Why use an interferometer?
A)
Its two widely-spaced mirrors act like
one giant telescope with increased collecting area.
B)
Its two widely-spaced mirrors act like one
giant telescope with increased resolving
power.
C)
By putting one mirror above the other you
can make the instrument much smaller.
D)
It can detect light at wavelengths not
available to single telescopes.
Why use an interferometer?
A)
Its two widely-spaced mirrors act like
one giant telescope with increased collecting area.
B)
Its two widely-spaced mirrors act like one
giant telescope with increased resolving
power.
C)
By putting one mirror above the other you
can make the instrument much smaller.
D)
It can detect light at wavelengths not
available to single telescopes.
Which of the following astronomical objects
emit radiation mostly at non-visible
wavelengths?
A) dust clouds in space
B) hot gas surrounding black holes
C) cold interstellar gas clouds
D) all of the above
Which of the following astronomical objects
emit radiation mostly at non-visible
wavelengths?
A) dust clouds in space
B) hot gas surrounding black holes
C) cold interstellar gas clouds
D) all of the above
Do astronomers use ground-based X-ray telescopes?
A)
Yes, because they can penetrate gas clouds.
B)
No, because no astronomical objects emit xrays.
C)
No, because x-rays cannot get through the
Earth's atmosphere.
D)
No, because astronomers have not yet
devised detectors for x-rays.
Do astronomers use ground-based X-ray telescopes?
A)
Yes, because they can penetrate gas clouds.
B)
No, because no astronomical objects emit xrays.
C)
No, because x-rays cannot get through the
Earth's atmosphere.
D)
No, because astronomers have not yet
devised detectors for x-rays.
Why does the useful resolving power of a groundbased telescope not match it's theoretical value?
A)
Mirrors can't be built accurately
enough.
B)
The atmosphere blurs the image,
decreasing the resolving power.
C)
Mirrors cannot collect enough light to
reach their theoretical expectations.
D) The theoretical value can only be
reached when there is a Full Moon.
Why does the useful resolving power of a groundbased telescope not match it's theoretical value?
A)
Mirrors can't be built accurately
enough.
B)
The atmosphere blurs the image,
decreasing the resolving power.
C)
Mirrors cannot collect enough light to
reach their theoretical expectations.
D) The theoretical value can only be
reached when there is a Full Moon.
On some telescopes, actuators on the mirror
change its shape to match distortions in the
atmosphere. What is this technique called?
A) Actuary observing
B) Interferometry.
C) Refraction
D) Adaptive Optics
On some telescopes, actuators on the mirror
change its shape to match distortions in the
atmosphere. What is this technique called?
A) Actuary observing
B) Interferometry.
C) Refraction
D) Adaptive Optics
Which of the following is a reason to build an
observatory in space?
A) They are much less expensive than
ground-based observatories.
B) They can last forever.
C) To avoid atmospheric blurring.
D) There is no good reason to build a
space-based observatory.
Which of the following is a reason to build an
observatory in space?
A) They are much less expensive than
ground-based observatories.
B) They can last forever.
C) To avoid atmospheric blurring.
D) There is no good reason to build a
space-based observatory.