Question 1
Question
Why do astronomers build radio telescopes?
Answer
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Radio waves give a different view of the universe
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Radio waves from space reach the Earth’s surface
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Radio telescopes can detect signals from aliens
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Radio telescopes can be much larger than optical telescopes
Question 2
Question
What type of telescope is most likely to suffer from chromatic aberration and have a low light-gathering power?
Answer
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a small diameter reflecting telescope
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a large diameter reflecting telescope
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a small diameter refracting telescope
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a large diameter refracting telescope
Question 3
Question
When does chromatic aberration occur in a telescope?
Answer
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when different colours of light do not focus at the same point in a reflecting telescope
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when different colours of light do not focus at the same point in a refracting telescope
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when light of different wavelengths gets absorbed by the mirror in a reflecting telescope
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when light of different wavelengths gets absorbed by the lens in a refracting telescope
Question 4
Question
What type of telescope is a radio telescope?
Answer
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reflecting
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refracting
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deflecting
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retracting
Question 5
Question
What type of telescope has a lens as its objective and contains no mirrors?
Answer
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deflecting
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reflecting
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refracting
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compound
Question 6
Question
How is the objective of most radio telescopes similar to the objective of a reflecting optical telescope?
Answer
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They are both bowl-shaped (concave)
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They are both hill-shaped (convex)
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They are typically the same size
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They are both made of metal
Question 7
Question
What type of primary is found in a reflecting telescope?
Answer
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prism
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mirror
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lens
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diffraction grating
Question 8
Question
You point your backyard reflecting telescope at the star Vega. Where does Vega’s light go?
Answer
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from the primary mirror, to the secondary mirror, to the eyepiece
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from the primary mirror to the eyepiece
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through the primary lens, to the secondary mirror, to the eyepiece
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through the primary lens, through the secondary lens, to the eyepiece
Question 9
Question
Which of the following best explains the concept of atmospheric windows?
Answer
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Holes in the Earth’s atmosphere allow ultraviolet radiation to reach the North and South poles
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X-ray radiation from space can see through the atmosphere to observe activities on the ground
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Only certain wavelengths of electromagnetic radiation from space reach the Earth’s surface
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The Earth’s atmosphere can be “closed” or “open” to electromagnetic radiation, depending on the weather
Question 10
Question
What is the main reason for building large optical telescopes?
Answer
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It’s the best way to see through clouds and other light-absorbers in the atmosphere
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It’s the best way to collect as much light as possible from faint objects
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It’s the best way to nullify the blurring effects of the Earth’s atmosphere and thus produce higher resolution images
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It’s the best way to magnify objects and make them brighter
Question 11
Question
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?
Answer
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Blue light will show finer details
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Red light will show finer details
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Both should be the same
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The amount of detail depends on the distance to the object
Question 12
Question
Which property of a telescope determines its light-gathering power?
Answer
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the focal length of the objective
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the focal length of the eyepiece
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the diameter of the objective
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the length of the telescope tube
Question 13
Question
What is the light-gathering power of a telescope directly proportional to?
Answer
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the diameter of the primary mirror or lens
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the focal length of the primary mirror or lens
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the length of the telescope tube
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the diameter of the eyepiece
Question 14
Question
Why can’t a telescope image be magnified to show any level of detail?
Answer
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Diffraction limits the amount of detail that is visible
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Telescopes only view a small region of the sky
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Magnification depends on focal length
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Resolving power depends on wavelength
Question 15
Question
Which of the following has the most light-gathering power?
Answer
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a telescope of 5 centimeters diameter and focal length of 50 centimeters
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a telescope of 6 centimeters diameter and focal length of 100 centimeters
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a telescope of 2 centimeters diameter and focal length of 100 centimeters
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a telescope of 3 centimeters diameter and focal length of 75 centimeters
Question 16
Question
How is the resolving power of a telescope defined?
Answer
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It is a measure of the minimum angular separation that can be seen with the telescope
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It is a measure of the amount of light that the telescope can gather in one second
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It is the separation between the objective and the image
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It is a measure of how blurry objects appear in the telescope
Question 17
Question
What happens to a telescope’s light-gathering power and resolving power when you increase its diameter?
Answer
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Its light-gathering power and resolving power both increase
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Its light-gathering power increases and its resolving power decreases
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Its light-gathering power decreases and its resolving power increases
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Its light-gathering power and resolving power both decrease
Question 18
Question
What can be done to improve the resolving power of ground-based optical telescopes?
Answer
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Use them at longer wavelengths
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Equip them with an adaptive optics system
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Change them from reflectors to refractors
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Increase their focal length
Question 19
Question
The pupil of the human eye is approximately 0.8 centimeters in diameter when adapted to the dark. What is the ratio of the light-gathering power of a 1.6 meter telescope to that of the human eye?
Answer
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2 : 1
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20 : 1
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400 : 1
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40,000 : 1
Question 20
Question
What is the ratio of the light-gathering power of a 10-metre telescope to that of a 1-metre telescope?
Answer
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10 to 1
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1 to 10
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100 to 1
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1 to 100
Question 21
Question
The diagram below illustrates the layout and light path of a reflecting telescope of the __________design
Question 22
Question
A(n)___________is used to measure the brightness and colour of stars
Question 23
Question
300 nanometer light has a lower frequency than 500 nanometer light
Question 24
Question
X-rays easily penetrate the Earth’s atmosphere and reach the ground from space
Question 25
Question
What is the purpose of interferometry?
Answer
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It is used to improve the resolving power of telescopes
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It is used to decrease the chromatic aberration of a telescope
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It is used to make large X-ray and ultraviolet telescopes
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It allows radio telescopes to be within a few hundred feet of each other