Chapter 6 home work 11 Telescopes Flashcards Preview

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Flashcards in Chapter 6 home work 11 Telescopes Deck (65)
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1

Which of the following best describes what we mean by the focal plane of a telescope?

It is the lower surface of the telescope's primary lens or mirror.
It is the surface of the lens on the eyepiece, through which you would look to see objects in the telescope's field of view.
It is the upper surface of the telescope's primary lens or mirror.
It is the place where, if we mounted film or an electronic detector, we could get a clear (not blurry) image of an object viewed through the telescope.

It is the place where, if we mounted film or an electronic detector, we could get a clear (not blurry) image of an object viewed through the telescope.

2

When your eye forms an image, the _____ plays a role analogous to the detector in a camera.

pupil
retina
optic nerve
lens

retina

3

What does angular resolution measure?

The size of an image.
The angular size of the smallest features that the telescope can see.
The number of electromagnetic waves captured by an image.
The brightness of an image.

The angular size of the smallest features that the telescope can see.

4

What is the angular resolution of the human eye?

about 1 degree
about 1 arcsecond (1/3600 of a degree)
about 1 arcminute, or 1/60 of a degree
about 1 milliarcsecond

about 1 arcminute, or 1/60 of a degree

5

Which of the following statements best describes the two principle advantages of telescopes over eyes?

Telescopes can collect far more light with far greater magnification.
Telescopes collect more light and are unaffected by twinkling.
Telescopes have much more magnification and better angular resolution.
Telescopes can collect far more light with far better angular resolution

Telescopes can collect far more light with far better angular resolution.

6

Which of the following statements best describes the difference between a refracting telescope and a reflecting telescope?

A refracting telescope produces refracted images while a reflecting telescope produces reflected images.
It is much easier to make a large refracting telescope than a large reflecting telescope.
Reflecting telescopes make much clearer images than can refracting telescopes of the same size.
A refracting telescope uses a transparent glass lens to focus light while a reflecting telescope uses a mirror to focus light.

A refracting telescope uses a transparent glass lens to focus light while a reflecting telescope uses a mirror to focus light.

7

What do we mean by the diffraction limit of a telescope?

It describes the maximum exposure time for images captured with the telescope.
It is the angular resolution the telescope could achieve if nothing besides the size of its light-collecting area affected the quality of its images.
It is the maximum size to which any telescope can be built.
It describes the farthest distance to which the telescope can see.

It is the angular resolution the telescope could achieve if nothing besides the size of its light-collecting area affected the quality of its images.

8

Which of the following is not one of the three main categories of observation generally used by astronomers?

Spectroscopy to spread an object's light into a spectrum.
Filtering to look at just a single color from an object.
Imaging to get a picture of an astronomical objects.
Time monitoring to track how an object's brightness varies with time.

Filtering to look at just a single color from an object.

9

Suppose you want to determine the chemical composition of a distant planet or star. Which of the following will be most useful to have?

High angular resolution.
High spectral resolution.
High turbulence.
A radio telescope.

High spectral resolution.

10

Which of the following is always true about images captured with X-ray telescopes?

They are always very pretty.
They show us light with extremely long wavelengths compared to the wavelengths of visible light.
They always have very high angular resolution.
They always are made with adaptive optics.
They are always shown with colors that are not the true colors of the objects that were photographed.

They are always shown with colors that are not the true colors of the objects that were photographed.

11

What do astronomers mean by light pollution?

Light pollution means contamination of light caused by chemicals in the Earth's atmosphere.
Light pollution is a type of air pollution created by lightweight gases such as hydrogen and helium.
Light pollution is a term used to describe the appearance of the sky in regions that are crowded with stars.
Light pollution is light from human sources that makes it difficult to see the stars at night.

Light pollution is light from human sources that makes it difficult to see the stars at night.

12

Which of the following effects is caused by atmospheric turbulence?

light pollution
magnification of images
twinkling of stars
diffraction of light

twinkling of stars

13

What is the purpose of adaptive optics?

It is a special technology that allows the Hubble Space Telescope to adapt to study many different types of astronomical objects.
It allows ground-based telescopes to observe ultraviolet light that normally does not penetrate the atmosphere.
It allows several small telescopes to work together like a single larger telescope.
It reduces blurring caused by atmospheric turbulence for telescopes on the ground.

It reduces blurring caused by atmospheric turbulence for telescopes on the ground.

14

Which of the following wavelength regions can be studied with telescopes on the ground?

all light with wavelengths shorter than infrared wavelengths
infrared, visible, and ultraviolet light.
all light with wavelengths longer than ultraviolet wavelengths
radio, visible, and very limited portions of the infrared and ultraviolet regions

radio, visible, and very limited portions of the infrared and ultraviolet regions

15

What is the purpose of interferometry?

It allows two or more small telescopes to achieve the angular resolution of a much larger telescope.
It is designed to prevent light pollution from interfering with astronomical observations.
It allows two or more small telescopes to achieve a larger light-collecting area than they would have independently.
It reduces the twinkling of stars caused by atmospheric turbulence.

It allows two or more small telescopes to achieve the angular resolution of a much larger telescope.

16

Which of the following forms of light can be observed with telescopes at sea level?
Select all that apply.

X rays
ultraviolet light
visible light
infrared light
radio waves

visible light
radio waves

17

If our eyes were sensitive only to X rays, the world would appear __________.

gray, black, and white like a medical X ray
brighter than normal because X rays carry more energy than visible light photons
dark because X-ray light does not reach Earth’s surface
green, yellow, and orange, because those are the colors of X rays

dark because X-ray light does not reach Earth’s surface

18

If you had only one telescope and wanted to take both visible-light and ultraviolet pictures of stars, where should you locate your telescope?

on Earth’s surface
on a tall mountain
in an airplane
in space

in space

19

Shown following are six different types of light that travel to Earth from the Sun. Rank these types of light from left to right based on the altitude in the atmosphere where they are completely absorbed, from highest to lowest (Earth’s surface). If two (or more) of the choices reach the same altitude or the surface, rank them as equal by dragging one on top of the other(s).

x-rays
most ultra violet light
most infrared light
green visble light
most radio waves

x-rays
most ultra violet light
most infrared light

Same: green visble light
most radio waves

20

Sort each of the astronomical questions below into the appropriate bin based on the type of observation you would need to perform to answer it. Imaging

How lare is the Andromeda Galaxy?
Are stars in the Orion Nebula surrounded by dusty disks of gas?
What are the major surface features of Mars?
What is the temperature of Jupiter's atmosphere?
Is the star Vega moving toward us or away from us?
What is the chemical composition of the Crab Nebula?
Does the star Mira vary in brightness?
Is the X-ray emission from the galactic center steady or changing?

How lare is the Andromeda Galaxy?
Are stars in the Orion Nebula surrounded by dusty disks of gas?
What are the major surface features of Mars?

21

Sort each of the astronomical questions below into the appropriate bin based on the type of observation you would need to perform to answer it. Spectroscopy

How lare is the Andromeda Galaxy?
Are stars in the Orion Nebula surrounded by dusty disks of gas?
What are the major surface features of Mars?
What is the temperature of Jupiter's atmosphere?
Is the star Vega moving toward us or away from us?
What is the chemical composition of the Crab Nebula?
Does the star Mira vary in brightness?
Is the X-ray emission from the galactic center steady or changing?

What is the temperature of Jupiter's atmosphere?
Is the star Vega moving toward us or away from us?
What is the chemical composition of the Crab Nebula?

22

Sort each of the astronomical questions below into the appropriate bin based on the type of observation you would need to perform to answer it. Timing

How lare is the Andromeda Galaxy?
Are stars in the Orion Nebula surrounded by dusty disks of gas?
What are the major surface features of Mars?
What is the temperature of Jupiter's atmosphere?
Is the star Vega moving toward us or away from us?
What is the chemical composition of the Crab Nebula?
Does the star Mira vary in brightness?
Is the X-ray emission from the galactic center steady or changing?

Does the star Mira vary in brightness?
Is the X-ray emission from the galactic center steady or changing?

23

Each of the following statements describes an astronomical measurement. Place each measurement into the appropriate bin based on the type of telescope you would use to make it. Infrared Telescope

Determine the surface temperature of Venus
Study a dense cloud of cold gas in space
Measure the brightness of a star that is similar to our sun
Obtain a spectrum of the sunlight reflected by Mars.
Observe the hot (1-million K) gas in the Sun's corona.
Look for high-energy radiation from a supernova.

Determine the surface temperature of Venus
Study a dense cloud of cold gas in space

24

Each of the following statements describes an astronomical measurement. Place each measurement into the appropriate bin based on the type of telescope you would use to make it. Visible light telescope

Determine the surface temperature of Venus
Study a dense cloud of cold gas in space
Measure the brightness of a star that is similar to our sun
Obtain a spectrum of the sunlight reflected by Mars.
Observe the hot (1-million K) gas in the Sun's corona.
Look for high-energy radiation from a supernova.

Measure the brightness of a star that is similar to our sun
Obtain a spectrum of the sunlight reflected by Mars.

25

Each of the following statements describes an astronomical measurement. Place each measurement into the appropriate bin based on the type of telescope you would use to make it. X-ray telescope

Determine the surface temperature of Venus
Study a dense cloud of cold gas in space
Measure the brightness of a star that is similar to our sun
Obtain a spectrum of the sunlight reflected by Mars.
Observe the hot (1-million K) gas in the Sun's corona.
Look for high-energy radiation from a supernova.

Observe the hot (1-million K) gas in the Sun's corona.
Look for high-energy radiation from a supernova.

26

Why does the Sun's image look distorted in shape at sunset?

The distortion arises because of the way air affects the paths of light.
The distortion is an artifact of the photographic process that your eyes would not actually see.
Air scatters different colors of light by different amounts.
The distortion is an illusion that you notice by eye but does not show up in photographs.

The distortion arises because of the way air affects the paths of light.

27

Suppose you have a camera attached to a telescope, and you want to record an image of a very faint galaxy. Which of the following will help the most?

a lot of pixels and a long exposure time
a small number of pixels and a long exposure time
a small number of pixels and a short exposure time
a lot of pixels and a short exposure time

a lot of pixels and a long exposure time

28

Suppose you have two small photographs of the Moon. Although both look the same at small size, when you blow them up to poster size one of them still looks sharp while the other one becomes fuzzy (grainy) looking. Which of the following statements is true?

Both photographs have the same angular resolution, because they are both photographs of the same object.
Both photographs have the same angular resolution, because they were both printed at the same sizes in each case.
The one that looks fuzzy at large size has better angular resolution (smaller) than the one that looks sharp.
The one that still looks sharp at large size has better (smaller) angular resolution than the one that looks fuzzy.

The one that still looks sharp at large size has better (smaller) angular resolution than the one that looks fuzzy.

29

The angular separation of two stars is 0.1 arcseconds and you photograph them with a telescope that has an angular resolution of 1 arcsecond. What will you see?

You will see two distinct stars in your photograph.
The stars will not show up at all in your photograph.
The two stars will appear to be touching, looking rather like a small dumbbell.
The photo will seem to show only one star rather than two.

The photo will seem to show only one star rather than two.

30

How does the light-collecting area of an 8-meter telescope compare to that of a 2-meter telescope?

The 8-meter telescope has 16 times the light-collecting area of the 2-meter telescope.
The 8-meter telescope has 8 times the light-collecting area of the 2-meter telescope.
The answer cannot be determined from the information given in the question.
The 8-meter telescope has 4 times the light-collecting area of the 2-meter telescope.

The 8-meter telescope has 16 times the light-collecting area of the 2-meter telescope.