ASTRO CH. 6 Reading / Concept Quiz

Which of the following best describes what we mean by the focal plane of a telescope? A. 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. B. It is the lower surface of the telescope's primary lens or mirror. C. 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. D. It is the upper surface of the telescope's primary lens or mirror.

A. 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.

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

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

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

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

Which of the following statements best describes the two principle advantages of telescopes over eyes? A. Telescopes can collect far more light with far better angular resolution. B. Telescopes collect more light and are unaffected by twinkling. C. Telescopes can collect far more light with far greater magnification. D. Telescopes have much more magnification and better angular resolution.

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

Why does the Sun's image look distorted in shape at sunset? A. The distortion arises because of the way air affects the paths of light. B. The distortion is an artifact of the photographic process that your eyes would not actually see. C. The distortion is an illusion that you notice by eye but does not show up in photographs. D. Air scatters different colors of light by different amounts.

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

Which of the following best describes why radio telescopes are generally much larger in size than telescopes designed to collect visible light? A.Getting an image of the same angular resolution requires a much larger telescope for radio waves than for visible light. B.Objects that emit radio waves are always much larger than objects that emit visible light, and therefore require larger telescopes. C.It is because radio telescopes are used in the daytime and visible light telescopes are used at night. D.Radio telescopes are designed to collect sound rather than light.

A.Getting an image of the same angular resolution requires a much larger telescope for radio waves than for visible light.

Which of the following is not an advantage of the Hubble Space Telescope over ground-based telescopes? A.It is closer to the stars. B.It never has to close because of cloudy skies. C.It can observe infrared and ultraviolet light, as well as visible light. D.Stars do not twinkle when observed from space.

A.It is closer to the stars.

What do we mean by the diffraction limit of a telescope? A. It describes the farthest distance to which the telescope can see. B. 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. C. It is the maximum size to which any telescope can be built. D.It describes the maximum exposure time for images captured with the telescope.

B. 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.

Consider two future observatories in space. Observatory X consists of a single 50-meter telescope. Observatory Y is an interferometer consisting of five 10-meter telescopes, spread out over a region 100 meters across. Which observatory can detect dimmer stars, and which one can see more detail in its images? (Assume all else is equal, such as quality of optics, types of instruments, and so on.) A.Observatory X can detect dimmer stars, and Observatory Y reveals more detail in images. B.Observatory X both detects dimmer stars and reveals more detail in images. C.Both observatories have the same capabilities, but Observatory Y would be cheaper to build. D.Observatory Y can detect dimmer stars, and Observatory X reveals more detail in images. E.Observatory Y both detects dimmer stars and reveals more detail in images.

A.Observatory X can detect dimmer stars, and Observatory Y reveals more detail in images.

Which of the following studies is best suited to astronomical observations that fall into the category called time monitoring? A.Studying how a star's brightness varies over a period of 3 years. B.Studying how different planets differ in their surface compositions. C.Measuring the rotation rate of a distant star. D.Determining the age of the solar system.

A.Studying how a star's brightness varies over a period of 3 years.

Suppose you want to determine the chemical composition of a distant planet or star. Which of the following will be most useful to have? A. High turbulence. B. High spectral resolution. C. High angular resolution. D. A radio telescope.

B. High spectral resolution.

Suppose you have a camera attached to a telescope, and you want to record an image of a faint galaxy. Which of the following will help the most? A. a small number of pixels and a short exposure time B. a lot of pixels and a long exposure time C.a lot of pixels and a short exposure time D.a small number of pixels and a long exposure time

B. a lot of pixels and a long exposure time

Which of the following wavelength regions can be studied with telescopes on the ground? A. all light with wavelengths shorter than infrared wavelengths B. radio, visible, and very limited portions of the infrared and ultraviolet regions C. infrared, visible, and ultraviolet light. D. all light with wavelengths longer than ultraviolet wavelengths

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

Which of the following telescopes benefits most from adaptive optics? A.The Hubble Space telescope B.The Keck I telescope on Mauna Kea C.The Chandra X-ray Observatory D.The Arecibo radio telescope in Puerto Rico

B.The Keck I telescope on Mauna Kea

Why are astronomers interested in building observatories capable of detecting neutrinos, cosmic rays, and gravitational waves? A.These things are emitted from the same objects that emit X rays, but unlike X rays, they can be detected with observatories on the ground. B.These things are not forms of light, and therefore can provide different types of information than light about objects that emit them. C.These things are the highest energy forms of light, even more energetic than gamma rays, and therefore can tell us about explosive processes in the universe. D.These things should in principle be much easier to detect than light, which means we could build these observatories cheaply.

B.These things are not forms of light, and therefore can provide different types of information than light about objects that emit them.

Why can't X-ray and gamma-ray telescopes use the same designs as visible-light telescopes? A.X rays and gamma rays do not penetrate Earth's atmosphere. B.X rays and gamma rays have so much energy that they cannot be reflected in the same way as visible light. C.X rays and gamma rays are so intense that they would melt the glass in a visible-light telescope. D.Visible-light telescopes can only reflect light that we see, not any other kind of light.

B.X rays and gamma rays have so much energy that they cannot be reflected in the same way as visible light.

The Chandra X-ray Observatory must operate in space because __________________________. A.it was built by NASA. B.X rays do not penetrate Earth's atmosphere C.X-ray telescopes require the use of grazing incidence mirrors D.X rays are too dangerous to be allowed on the ground

B.X rays do not penetrate Earth's atmosphere

Which of the following is not one of the three main categories of observation generally used by astronomers? A. Spectroscopy to spread an object's light into a spectrum. B. Time monitoring to track how an object's brightness varies with time. C. Filtering to look at just a single color from an object. D. Imaging to get a picture of an astronomical objects.

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

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

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

What is the angular resolution of the human eye? A. about 1 arcsecond (1/3600 of a degree) B. about 1 degree C. about 1 arcminute, or 1/60 of a degree D. about 1 milliarcsecond

C. about 1 arcminute, or 1/60 of a degree

How does the light-collecting area of an 8-meter telescope compare to that of a 2-meter telescope? A.The answer cannot be determined from the information given in the question. B.The 8-meter telescope has 4 times the light-collecting area of the 2-meter telescope. C.The 8-meter telescope has 16 times the light-collecting area of the 2-meter telescope. D.The 8-meter telescope has 8 times the light-collecting area of the 2-meter telescope.

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

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, whereas the other one becomes fuzzy (grainy) looking. Which of the following statements is true? A.Both photographs have the same angular resolution because they are both photographs of the same object. B.The one that looks fuzzy at large size has better angular resolution (smaller) than the one that looks sharp. C.The one that still looks sharp at large size has better (smaller) angular resolution than the one that looks fuzzy. D.Both photographs have the same angular resolution because they were both printed at the same sizes in each case.

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

Chapter 6 Concept Quiz

Chapter 6 Concept Quiz

Chapter 6 Reading Quiz

Chapter 6 Reading Quiz

Which of the following statements best describes the difference between a refracting telescope and a reflecting telescope? A. Reflecting telescopes make much clearer images than can refracting telescopes of the same size. B. A refracting telescope produces refracted images, whereas a reflecting telescope produces reflected images. C. It is much easier to make a large refracting telescope than a large reflecting telescope. D. A refracting telescope uses a transparent glass lens to focus light, whereas a reflecting telescope uses a mirror to focus light.

D. A refracting telescope uses a transparent glass lens to focus light, whereas a reflecting telescope uses a mirror to focus light.

What does angular resolution measure? A. The number of electromagnetic waves captured by an image. B. The size of an image. C. The brightness of an image. D. The angular size of the smallest features that the telescope can see.

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

When your eye forms an image, the _____ plays a role analogous to the detector in a camera. A. optic nerve B. lens C. pupil D. retina

D. retina

Which of the following effects is caused by atmospheric turbulence? A. light pollution B. diffraction of light C. magnification of images D. twinkling of stars

D. twinkling of stars

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

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

Which of the following is not a reason why telescopes tend to be built on mountaintops that are relatively far from cities and are in regions with dry climates? A.Mountaintops far from cities are generally subject to less light pollution than locations nearer to cities. B.Dry regions mean less rain and clouds, and mountaintops in dry regions may even allow some infrared observations. C.Being on a high mountain top means being relatively high in the atmosphere, which tends to limit turbulence. D.The thin air on mountaintops makes the glass in telescope mirrors less susceptible to warping.

D.The thin air on mountaintops makes the glass in telescope mirrors less susceptible to warping.

The stars in our sky twinkle in brightness and color because of ______. A.light pollution B.rapid changes in the brightness and colors of stars caused by changes in their spectra C.the bubbling and boiling of gases on the surfaces of stars D.turbulence in the Earth's atmosphere

D.turbulence in the Earth's atmosphere

Which of the following is always true about images captured with X-ray telescopes? A. They show us light with extremely long wavelengths compared to the wavelengths of visible light. B. They always have high angular resolution. C. They always are made with adaptive optics. D. They are always pretty. E. They are always shown with colors that are not the true colors of the objects that were photographed.

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