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1 Name: Class: _ Date: _ Practice Quiz 4 Multiple Choice Identify the choice that best completes the statement or answers the question. 1. What is the wavelength of the longest wavelength light that can be seen with the human eye? a. 400 nm b nm c nm d. 700 nm e m 2. has (have) wavelengths that are longer than visible light. a. Gamma-rays b. Ultraviolet light c. Infrared radiation d. X-rays e. a, b and d above 3. has (have) wavelengths that are shorter than visible light. I. Gamma-rays II. Ultraviolet light III. Infrared radiation IV. X-rays a. I & II b. I & IV c. II & III d. II, III, & IV e. I, II, & IV 4. Astronomers build telescopes on tops of mountains because a. there is less air to dim the light. b. the seeing is better. c. CCDs work better when there is less oxygen in the air. d. all of the above e. a and b 5. Radio telescopes have poor resolving power because a. their diameters are so large. b. the energy they receive is not electromagnetic radiation. c. radio waves have long wavelengths. d. a and b 1

2 Name: 6. Ultraviolet radiation from a star a. will not penetrate Earth's atmosphere and reach the ground. b. has a wavelength that is longer than the visible light emitted by the star. c. has a wavelength that is shorter than the x-rays emitted by the star. d. a and b e. b and c 7. A new generation of ground-based telescopes is currently being built that overcomes the limitations of the older large telescopes. Some of these new telescopes a. use segmented mirrors. b. use mirrors that are very thin. c. use active optics to control the shape of the mirror. d. all of the above. 8. Radio telescopes are important in astronomy because a. they can detect cool hydrogen. b. they have high magnification. c. the can detect interstellar dust clouds. d. they are very inexpensive to build on tops of mountains. e. they don't need to be as large as optical telescopes to achieve the same resolving power. 9. The sidereal drive of a telescope mounting must turn the telescope a. southward about the polar axis. b. eastward about the polar axis. c. westward about the polar axis. d. northward about the polar axis. 10. Far infrared astronomy must be done from high-flying aircraft because a. far infrared radiation is absorbed low in Earth's atmosphere. b. far infrared photons are quite energetic. c. far infrared telescopes are not very heavy. d. far infrared sources are very bright. 11. A is a piece of glass with many small parallel lines etched on its surface to produce a spectrum. a. grating b. spectrograph c. photometer d. charge-coupled device e. prism 2

3 Name: 12. The technique of connecting multiple telescopes together to combine the images from each telescope is known as a. abberation. b. resolving power. c. active optics. d. adaptive optics. e. interferometry. 13. Interferometry a. is used to improve the resolving power. b. decreases the chromatic aberration of a telescope. c. works only for large x-ray and ultraviolet telescopes. d. requires that radio telescopes be within a few hundred feet of each other. 14. The 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 e. spherical aberration 15. Which of the following telescopes must be used above Earth's atmosphere? a. an optical telescope b. the VLBI telescope c. an x-ray telescope d. a radio telescope 16. The energy of a photon a. is proportional to the wavelength of the light. b. is inversely proportional to the wavelength of the light. c. depends only on the speed of the light. d. depends only on the mass of the photon. e. depends on both the mass and speed of the photon. 17. Long wavelength visible light a. will have a greater energy than short wavelength visible light. b. will have a speed that is faster than short wavelength light. c. has a higher frequency than short wavelength visible light. d. will appear blue in color to the average human eye. e. will appear red in color to the average human eye. 18. Which of the following types of electromagnetic radiation has the highest frequency? c. radio 3

4 Name: 19. Which of the following types of electromagnetic radiation has the smallest frequency? c. radio 20. Which of the following types of electromagnetic radiation has the greatest energy? c. radio 21. Which of the following types of electromagnetic radiation has the lowest energy? c. ultraviolet 22. An achromatic lens a. is used to correct spherical aberration in reflecting telescopes. b. is used to correct chromatic aberration in refracting telescopes. c. is used to correct spherical aberration in refracting telescopes. d. is used to correct chromatic aberration in reflecting telescopes. e. contains two mirrors and focuses the light back through the primary mirror. 23. is absorbed by water in Earth's atmosphere and requires that telescopes for observing at these wavelengths be placed on mountain tops or in space. a. Infrared radiation b. Ultraviolet radiation c. Radio wave radiation d. X-ray radiation e. Visible light 24. Increasing the diameter of a telescope I. increases its light gathering power. II. increases its resolving power. III. increases it magnifying power. IV. increases its chromatic aberration. a. I, II, III, & IV b. I, II, & III c. I, II, & IV d. III & IV e. I & II 4

5 Name: 25. Which of the following features 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 objective d. Length of the telescope tube e. None of the above. 26. What is the relationship between color and wavelength for light? a. Wavelength increases from blue light to red light b. Wavelength decreases from blue light to red light c. All colors of light have the same wavelength. d. Wavelength depends on intensity not color. 27. The main reason for building large optical telescopes on the Earth's surface is a. that there is a lot of money in science that needs to get spent. b. to collect as much light as possible from faint objects. c. to nullify the blurring effects of the Earth's atmosphere and thus produce higher resolution images. d. to bring astronomical objects closer to make them brighter. e. that the warm temperatures of the Earth's surface allow for easier telescope operation. 28. What statement below best describes the refraction of light? a. The absorption of light as it travels though a dense, transparent material. b. The spreading out of white light according to wavelength. c. The change in direction of a light ray as it passes to a medium of different optical density. d. The change in direction of a ray of light as it reflects off a surface. 29. Chromatic aberration occurs in a telescope when. a. reflecting; different colors of light do not focus at the same point. b. refracting; different colors of light do not focus at the same point. c. reflecting; light of different wavelengths get absorbed by the mirror. d. refracting; light of different wavelengths get absorbed by the lens. 30. The main reason for positioning many radio telescopes across a large area and combining the signals is a. to observe more objects in a shorter amount of time. b. provide a backup system if one or more of the telescopes go down. c. to produce higher resolution images. d. to avoid interference between signals from the separate telescopes. e. to account for the motion of objects in the sky as a result of the Earth's rotation. 31. Radio telescopes are telescopes. a. Reflecting b. Refracting c. Deflecting d. Compound e. Retracting 5

6 Name: 32. The largest single dish radio telescope is. a. suspended on cables in a valley b. buried deep in a mine underground c. orbiting in space d. suspended from balloons in the upper atmosphere Essay 33. How do atmospheric windows limit observations made from Earth's surface? 34. Why must telescopes that observe in the far infrared be cooled? 35. What are sources of light pollution and how do those affects astronomical observations? 6

7 Practice Quiz 4 Answer Section MULTIPLE CHOICE 1. ANS: D PTS: 1 2. ANS: C PTS: 1 3. ANS: E PTS: 1 4. ANS: E PTS: 1 5. ANS: C PTS: 1 6. ANS: A PTS: 1 7. ANS: D PTS: 1 8. ANS: A PTS: 1 9. ANS: C PTS: ANS: A PTS: ANS: A PTS: ANS: E PTS: ANS: A PTS: ANS: D PTS: ANS: C PTS: ANS: B PTS: ANS: E PTS: ANS: D PTS: ANS: C PTS: ANS: D PTS: ANS: E PTS: ANS: B PTS: ANS: A PTS: ANS: E PTS: ANS: C PTS: ANS: A PTS: ANS: B PTS: ANS: C PTS: ANS: B PTS: ANS: C PTS: ANS: A PTS: ANS: A PTS: 1 ESSAY 33. ANS: Answer not provided. PTS: 1 1