Deck 4: Astronomical Telescopes and Instruments: Extending Humanitys Vision

Question 1

What is the relationship between colour and wavelength for light?

A) Wavelength increases from blue light to red light.
B) Wavelength decreases from blue light to red light.
C) All colours of light have the same wavelength.
D) Wavelength depends on intensity, not colour.

Answer 1

Wavelength increases from blue light to red light.

Question 2

How do photons of blue light differ from photons of red light?

A) Blue light photons have more energy than photons of red light.
B) Blue light photons have a lower frequency than photons of red light.
C) Blue light photons have a longer wavelength than photons of red light.
D) Blue light photons travel faster than photons of red light.

Answer 2

Blue light photons have more energy than photons of red light.

Question 3

Which of the following statements about the Earth's atmosphere is true?

A) The atmosphere is transparent to most radio waves.
B) The atmosphere is opaque to most radio waves.
C) The atmosphere is transparent to X-rays.
D) The atmosphere is opaque to most visible wavelengths.

Answer 3

The atmosphere is transparent to most radio waves.

Question 4

In which way is a photon of blue light identical to a photon of red light?

A) energy
B) speed
C) wavelength
D) frequency

Question 5

Which of the following types of electromagnetic radiation has the lowest energy per photon?

A) X-rays
B) ultraviolet light
C) gamma rays
D) infrared radiation

Question 6

What does the word "radiation" mean when used by scientists?

A) invisible forms of light such as X-rays and radio waves
B) the light emitted by black holes and protostars
C) high-energy particles from nuclear reactors
D) anything that spreads out from a central source

Question 7

How does long-wavelength visible light appear to the average human eye?

A) invisible
B) green
C) blue
D) red

Question 8

Which form of electromagnetic radiation travels fastest?

A) gamma rays
B) radio waves
C) all electromagnetic radiation travels at the same speed
D) the speed of radiation depends on the brightness of the source

Question 9

Which of the following types of electromagnetic radiation is absorbed by ozone in the Earth's atmosphere?

A) infrared radiation
B) ultraviolet radiation
C) X-ray radiation
D) visible light

Question 10

Which of the following types of electromagnetic radiation has the greatest energy per photon?

A) X-rays
B) radio waves
C) gamma rays
D) infrared radiation

Question 11

Which of the following sequences of electromagnetic radiation shows the order of increasing energy correctly?

A) gamma rays, X-rays, infrared, radio
B) visible, ultraviolet, X-rays, gamma rays
C) visible, microwave, radio, infrared
D) infrared, visible, radio, X-rays

Question 12

Which of the following types of electromagnetic radiation is absorbed by water lower in the Earth's atmosphere, but can be detected by telescopes that are on mountaintops or are carried by aircraft?

A) infrared radiation
B) ultraviolet radiation
C) radio wave radiation
D) X-ray radiation

Question 13

Which of the following types of electromagnetic radiation has the smallest frequency?

A) X-rays
B) radio waves
C) visible light
D) infrared radiation

Question 14

Which of the following statements best describes the wavelength of a wave?

A) the measure of how strong the wave is
B) the distance between two adjacent peaks of the wave
C) the measure of how fast the wave is
D) the distance between a peak of the wave and the next trough

Question 15

Which of the following types of light has wavelengths that are shorter than the wavelengths of visible light?

A) gamma rays
B) radio waves
C) infrared radiation
D) microwaves

Question 16

Which of the following types of light has wavelengths that are longer than the wavelengths of visible light?

A) gamma rays
B) ultraviolet
C) infrared
D) X-rays

Question 17

What does a nanometre measure?

A) frequency
B) energy
C) mass
D) length

Question 18

How does the energy of a photon relate to the other properties of light?

A) Energy is directly proportional to the wavelength of the light.
B) Energy is inversely proportional to the wavelength of the light.
C) Energy depends only on the speed of the light.
D) Energy is inversely proportional to the frequency of the light.

Question 19

What is the longest wavelength of light that can be seen with the human eye?

A) 400 nanometres
B) 700 nanometres
C) 7000 nanometres
D) 3×10⁸ m

Question 20

What is a photon?

A) a type of electromagnetic radiation
B) a particle within the atmospheric window
C) a particle produced when light interacts with vacuum
D) a particle of light

Question 21

What is the main reason for building large optical telescopes?

A) It's the best way to see through clouds and other light-absorbers in the atmosphere.
B) It's the best way to collect as much light as possible from faint objects.
C) It's the best way to nullify the blurring effects of the Earth's atmosphere and thus produce higher resolution images.
D) It's the best way to magnify objects and make them brighter.

Question 22

Why can't a telescope image be magnified to show any level of detail?

A) Diffraction limits the amount of detail that is visible.
B) Telescopes only view a small region of the sky.
C) Magnification depends on focal length.
D) Resolving power depends on wavelength.

Question 23

Why do astronomers build radio telescopes?

A) Radio waves give a different view of the universe.
B) Radio waves from space reach the Earth's surface.
C) Radio telescopes can detect signals from aliens.
D) Radio telescopes can be much larger than optical telescopes.

Question 24

What is the light-gathering power of a telescope directly proportional to?

A) the diameter of the primary mirror or lens
B) the focal length of the primary mirror or lens
C) the length of the telescope tube
D) the diameter of the eyepiece

Question 25

You point your backyard reflecting telescope at the star Vega. Where does Vega's light go?

A) from the primary mirror, to the secondary mirror, to the eyepiece
B) from the primary mirror to the eyepiece
C) through the primary lens, to the secondary mirror, to the eyepiece
D) through the primary lens, through the secondary lens, to the eyepiece

Question 26

What type of telescope is a radio telescope?

A) reflecting
B) refracting
C) deflecting
D) retracting

Question 27

What is a similarity between radio and optical telescopes?

A) Both can observe from the Earth's surface.
B) Both are usually located on mountaintops.
C) Both are usually made as refracting telescopes.
D) Both can detect radiation with charge-coupled devices.

Question 28

How is the primary of most radio telescopes similar to the primary of a reflecting optical telescope?

A) They both focus electromagnetic radiation.
B) They both use glass to bend the path of light rays.
C) They are typically the same size.
D) They are both made of metal.

Question 29

What can be done to improve the resolving power of ground-based optical telescopes?

A) Use them at longer wavelengths.
B) Equip them with an adaptive optics system.
C) Change them from reflectors to refractors.
D) Increase their focal length.

Question 30

Which of the following best explains the concept of atmospheric windows?

A) Holes in Earth's atmosphere allow ultraviolet radiation to reach the North and South poles.
B) X-ray radiation from space can see through the atmosphere to observe activities on the ground.
C) Only certain wavelengths of electromagnetic radiation from space reach Earth's surface.
D) Earth's atmosphere can be "closed" or "open" to electromagnetic radiation, depending on the weather.

Question 31

By what factor is the light-collecting power of the James Webb Space Telescope (6.6 m primary mirror) greater than the light-collecting power of the Hubble Space Telescope (2.4 m primary mirror)?

A) 2.75
B) 7.56
C) 15.84
D) It depends on which wavelength they observe.

Question 32

How is the resolving power of a telescope defined?

A) It is a measure of the telescope's ability to reveal fine detail.
B) It is a measure of the amount of light that the telescope can gather in one second.
C) It is the separation between the primary and the image.
D) It is a measure of how blurry objects appear in the telescope.

Question 33

An astronomer takes two pictures of the same object using the Hubble Space Telescope. One picture is taken with red light and one with blue light. Which one would you expect to show finer details?

A) Blue light will show finer details.
B) Red light will show finer details.
C) Both should be the same.
D) The amount of detail depends on the distance to the object.

Question 34

Which property of a telescope determines its light-gathering power?

A) the focal length of the objective
B) the focal length of the eyepiece
C) the diameter of the primary
D) the length of the telescope tube

Question 35

What happens to a telescope's light-gathering power and resolving power when you increase its diameter?

A) Its light-gathering power and resolving power both increase.
B) Its light-gathering power increases and its resolving power decreases.
C) Its light-gathering power decreases and its resolving power increases.
D) Its light-gathering power and resolving power both decrease.

Question 36

Suppose a large refracting telescope and a large reflecting telescope have the same diameter primary. What can you conclude about the difference between the two telescopes?

A) The refracting telescope will have a greater light-collecting power than the reflecting telescope.
B) The refracting telescope will have a longer focal length than the reflecting telescope.
C) The refracting telescope will have less resolving power than the reflecting telescope.
D) The refracting telescope will suffer from more optical distortion than the reflecting telescope.

Question 37

Which of the following has the most light-gathering power?

A) a telescope of 5 centimetres diameter and focal length of 50 centimetres
B) a telescope of 6 centimetres diameter and focal length of 100 centimetres
C) a telescope of 2 centimetres diameter and focal length of 100 centimetres
D) a telescope of 3 centimetres diameter and focal length of 75 centimetres

Question 38

What type of telescope has a lens as its primary and contains no mirrors?

A) deflecting
B) reflecting
C) refracting
D) compound

Question 39

The pupil of the human eye is approximately 0.8 centimetres in diameter when adapted to the dark. What is the ratio of the light-gathering power of a 1.6 metre telescope to that of the human eye?

A) 2 : 1
B) 4 : 1
C) 200 : 1
D) 40,000 : 1

Question 40

What type of primary is found in a reflecting telescope?

A) prism
B) mirror
C) lens
D) diffraction grating

Question 41

What is the main reason for positioning many radio telescopes across a large area and combining the signals?

A) to provide a backup system if one or more of the telescopes go down
B) to produce higher resolution images
C) to prevent interference between signals from the separate telescopes
D) to compensate for the motion of objects in the sky as a result of the Earth's rotation

Question 42

What is the ratio of the light-gathering power of a 10-metre telescope to that of a 1-metre telescope?

A) 10 to 1
B) 1 to 10
C) 100 to 1
D) 1 to 100

Question 43

Which of the following statements best explains why stars twinkle?

A) variations in the diffraction limit of the atmosphere
B) bending of light rays by turbulent layers in the atmosphere
C) differential bending of visible wavelengths in the middle atmosphere
D) bending of ultraviolet rays as they reflect back into space

Question 44

Space telescope A has a diameter of 2.4 metres; space telescope B has a diameter of 6.5 metres. If they take pictures with the same wavelength of light, which telescope will be better able to make separate images of two stars close together on the sky?

A) Telescope A will do better.
B) Telescope B will do better.
C) Neither one; if they work at the same wavelength, they will give the same results.
D) Neither one; even in space, telescopes cannot separate objects that are near each other.

Question 45

A telescope has a primary with a focal length of 1500 mm and an eyepiece with a focal length of 15 mm. What is the magnifying power of the telescope?

A) 0.01
B) 15
C) 100
D) 1500

Question 46

Which feature(s) of a telescope determine its magnifying power?

A) diameter of the primary only
B) focal length of the primary only
C) primary diameter and focal length of the eyepiece
D) focal length of the primary and eyepiece

Question 47

An astronomy graduate student takes a long-exposure picture with a CCD camera but forgets to turn on sidereal tracking. What will the picture look like?

A) The picture will be blank.
B) The picture will be blurry.
C) The picture will have long, thin star trails.
D) The picture will have many false colours.

Question 48

An array of telescopes work together as an interferometer. How would the interferometer's performance change if many more telescopes were added between the existing telescopes?

A) The resolving power and the light-collecting power would increase.
B) The resolving power would increase and the light-collecting power would stay the same.
C) The resolving power would stay the same and the light-collecting power would increase.
D) The resolving power would decrease and the light-collecting power would stay the same.

Question 49

What feature of a telescope is a measure of its ability to show fine detail and depends on the diameter of the objective?

A) light-gathering power
B) focal length
C) magnifying power
D) resolving power

Question 50

What is the term for the technique of connecting multiple telescopes together to combine the images from each telescope?

A) resolving power
B) active optics
C) adaptive optics
D) interferometry

Question 51

Which of the following could you use to observe high-energy eruptions caused by black holes?

A) a gamma-ray telescope on a mountaintop
B) an infrared telescope at sea level on Earth
C) a radio telescope in space
D) an X-ray telescope in space

Question 52

Why do astronomers build telescopes on tops of mountains?

A) There is less air to dim the light.
B) The weather is better on mountaintops.
C) Electronic cameras work better when there is less oxygen in the air.
D) Mountaintops are closer to objects in space.

Question 53

Radio telescopes are affected by interference from human-made radio devices. What is the equivalent problem for optical telescopes?

A) light pollution
B) seeing
C) clouds and water vapour
D) atmospheric turbulence

Question 54

What is the purpose of interferometry?

A) It is used to improve the resolving power of telescopes.
B) It is used to reduce the distortions caused by turbulence in the atmosphere.
C) It is used to make large X-ray and ultraviolet telescopes.
D) It allows radio telescopes to be within a few hundred metres of each other.

Question 55

An array of telescopes work together as an interferometer. How would the interferometer's performance change if the same telescopes were used but were spaced farther apart?

A) The resolving power and the light-collecting power would increase.
B) The resolving power would increase and the light-collecting power would stay the same.
C) The resolving power and the light-collecting power would decrease.
D) The resolving power would decrease and the light-collecting power would stay the same.

Question 56

What is the purpose of adaptive optics?

A) to improve diffraction limit and increase magnification power for ground-based telescopes
B) to increase the light-gathering power of ground-based telescopes
C) to compensate for the distorting effect of atmospheric turbulence in ground-based telescopes
D) to see through clouds and remove blurring for ground-based telescopes

Question 57

What is the most important reason why optical telescopes are often built on mountaintops?

A) The air is thinner.
B) The atmosphere is more steady.
C) The view of the horizon is not obscured.
D) The air is drier.

Question 58

A new generation of ground-based telescopes are currently being built to overcome the limitations of the older large telescopes. How are these different from previous telescopes?

A) They can eliminate light pollution.
B) They can detect X-rays.
C) They use computers to control the shape of the mirror.
D) They can see through clouds.

Question 59

The primary mirror of space telescope A has a diameter that is twice as large as the primary mirror of space telescope B. How will their resolving powers compare?

A) Telescope A will have twice as much resolving power as telescope B.
B) Telescope A will have half as much resolving power as telescope B.
C) They will have the same resolving power.
D) It depends on which wavelengths of light each telescope observes.

Question 60

Why do radio telescopes have poor resolving power?

A) Their diameters are extremely large.
B) The energy they receive is not electromagnetic radiation.
C) Radio waves have long wavelengths.
D) Radio waves travel at slow speeds.

Question 61

What is the most common design of large optical telescopes?

A) Cassegrain focus
B) Newtonian focus
C) Schmidt-Cassegrain focus
D) refracting

Question 62

The Earth's atmosphere blocks most forms of electromagnetic radiation from entering, except for _______________ ___________ and ______________ _____________.

Question 63

The main lens or mirror of a telescope is called the ____________________.

Question 64

The process of combining signals from separate telescopes to improve resolution is called _______________________.

Question 65

Why must far-infrared astronomy be done from high-flying aircraft or spacecraft?

A) Far-infrared radiation is absorbed low in the Earth's atmosphere.
B) Far-infrared photons are quite energetic.
C) Far-infrared photons have long wavelengths.
D) Far-infrared radiation is reflected from the top of the Earth's atmosphere.

Question 66

A(n) ____________________ telescope has a primary that is a lens.

Question 67

Which of the following observations could be made with Canada's CHIME telescope?

A) X-ray radiation from black holes
B) optical images of distant galaxies
C) radio waves from a pulsar
D) infrared images of hydrogen clouds

Question 68

Which of the following telescope types must be used above the Earth's atmosphere?

A) an optical telescope
B) a refracting telescope
C) an X-ray telescope
D) a radio telescope

Question 69

A(n) _________________ _____________________ uses a mirror as its objective.

Question 70

Far-infrared telescopes have to be cooled, but visible-light telescopes do not. Why not?

A) Far-infrared radiation is absorbed by the Earth's atmosphere.
B) Visible-light telescopes detect light from cool objects.
C) Far-infrared telescopes can only work in space.
D) Telescopes are not hot enough to emit visible light.

Question 71

Which of the following is not required for the normal operation of Canada's CHIME telescope?

A) sidereal tracking
B) interferometry
C) protection from radio interference
D) Earth's rotation

Question 72

What is the term for a piece of glass with many small parallel lines etched on its surface, used to produce a spectrum?

A) spectrograph
B) grating
C) charge-coupled device
D) prism

Question 73

What is "false" about false-colour images?

A) They are images created by computer simulations.
B) The colours do not represent the colours humans can see.
C) The colours are exaggerated for visual effect.
D) They are images created by artists, not astronomers.

Question 74

What is the diameter of the largest radio dish in the world?

A) 10 m
B) 50 m
C) 100 m
D) 500 m

Question 75

Suppose that you wanted to know how bright a star was at several different wavelengths of light. What kind of instrument would you use?

A) a spectrograph
B) a seismograph
C) a photograph
D) a chromatic aberrator

Question 76

What is Very Long Baseline Interferometry (VLBI)?

A) a method to observe the largest possible areas of the sky in radio waves
B) a method to observe the largest wavelength optical light
C) linking optical telescopes in different hemispheres to observe the whole sky
D) linking radio telescopes together electronically to provide very high resolution

Question 77

The _______________ _____________ is a measure of the finest detail that can be seen in an image.

Question 78

What is the most important reason for putting an optical telescope in space?

A) An optical telescope in space observes radiation that does not pass through the Earth's atmosphere.
B) A telescope in space is closer to the objects it observes.
C) Telescopes in space are not subject to the blurring effects of the Earth's atmosphere.
D) An optical telescope in space can be made much larger than one on the ground.

Question 79

Which of the following has a few million microscopic light detectors in an array typically measuring about the size of a postage stamp?

A) photographic plate
B) spectrograph
C) charge-coupled device
D) grating

Question 80

Which of the following types of radiation from a star cannot penetrate the Earth's atmosphere and reach the ground?

A) ultraviolet
B) visible
C) infrared
D) nuclear