ASTRO Exam (Chapters 5, 6, 15)

When white light passes through a cool cloud of gas, we see A. visible light B. inferred light C. thermal radiation D. an absorption line spectrum E. an emission line spectrum

an absorption line spectrum

Suppose you measure the parallax angle for a particular star to be 0.1 arc second. The distance to the star is A. 10 light-years B. 10 parsecs C. 0.1 light-year D. 0.1 parsec E. impossible to determine

10 parsecs

If two objects are the same size but one object is 3 times hotter than the other object, the hotter object emits A. 3 times more energy B. 9 times more energy C. 12 times more energy D. 81 times more energy E. none of the above

81 times more energy

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

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

Which of the following statements about apparent and absolute magnitudes is true? A. The magnitude system that we use now is based on a system used bu the ancient greeks over 2,000 years ago that classified stars by how bright they appeared B. A star with apparent magnitude 1 is brighter in the sky than one with apparent magnitude of 2 C. The absolute magnitude of a star i another measure of its luminosity D. A star's absolute magnitude is the apparent magnitude it would have if it were a distance of 10 parsecs from Earth E. All of the above

All of the above

True of False? The atomic mass number of an atom is equal to the number of protons in its nucleus.

False

True or False? A radio telescope and an optical telescope of the same size have the same angular resolution.

False

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

What is a CCD? A. It is an electronic detector that can be used in place of photographic film for making images B. It is an abbreviation for the world's largest operating telescope C. It refers to any king of instrument that can be hooked up to a telescope D. It is a unit by astronomers to measure angular resolution

It is an electronic detector that can be used in place of photographic film for making images

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. Stars do not twinkle when observed from space C. It can observe infrared and ultraviolet light, as well as visible light D. It never has to close because of cloudy skies

It is closer to the stars

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

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

What do astronomers mean by light pollution? A. Light pollution is a type of air pollution created by lightweight pases such as hydrogen and helium B. Light pollution is light from human sources that makes it difficult to see the stars at night C. Light pollution means contamination of light caused by chemical in the Earth's atmosphere D. 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

How are wavelength, frequency, and energy related for photons of light? A. Longer wavelength means lower frequency and lower energy B. Longer wavelength means higher frequency and lower energy C. Longer wavelength means higher frequency and higher energy D. Longer wavelength means lower frequency and higher energy E. There is no simple relationship because different photons travel at different speeds

Longer wavelength means lower frequency and lower energy

Which of the following is true about low-mass stars compared to high-mass stars on the main sequence? A. Low-mass stars are cooler and less luminous than high-mass stars B. Low-mass stars are hotter and more luminous than high-mass stars C. Low-mass stars are cooler but more luminous than high-mass stars D. Low-mass stars are hotter but less luminous han high-mass stars E. Low-mass stars have the same temperature and luminosity as high-mass stars

Low-mass stars are cooler and less luminous than high-mass stars

The spectral sequence in order of decreasing temperature is A. OFBAGKM B. OBAGFKM C. OBAFGKM D. ABFGKMO E. BAGFKMO

OBAFGKM

Which statement best describes the two principle advantages of the telescopes over eyes? A. Telescopes can collect far more light with far better angular resolution B. Telescopes can collect for more light with far greater magnification C. Telescopes have much more magnification and better angular resolution D. Telescopes collect more light and are unaffected by twinkling E. Telescopes can see farther without image distortion and can record more accurate colors

Telescopes can collect far more light with far better angular resolution

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

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

You observe the same spectral line in two stars that are identical in every way except that one rotates faster than the other. How does the specula line differ between the two? A. There is no difference B. The line in the faster rotating star is blueshifted C. The line in the faster rotating star is redshifted D. The line in the faster rotating star is broader E. The line in the faster rotating star is narrower

The line in the faster rotating star is broader

The angular separation of two stars is 0.1 arcseconds and you photograph them with a telescope that has an angular resolution of 1 arc second. 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. The photo will seem to show only one star rather than two D. You will see two distinct stars in your photograph

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

From the laboratory measurements, we know that a particular spectral line formed by hydrogen appears at a wavelength of 121.8 nm. What can we conclude? A. The star is moving toward us. B. The star is moving away from us. C. The star is getting hotter. D. The star is getting colder. E. The "star" is actually a planet

The star is moving away from us

We can learn a lot about the properties of a star by studying its spectrum. All the statements are true except A. The peak of the star's thermal emission tells us its temperature: Hotter stars peak at shorter (bluer) wavelengths. B. The total amount of light in the spectrum tells us the star's radius. C. We can identify chemical elements present in the star by recognizing patterns of spectral lines that correspond to particular chemicals. D. We can look at Doppler shifts of spectral lines to determine the star's speed toward or away from us.

The total amount of light in the spectrum tells us the star's radius

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

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

True or False? If the distance between us and a star is doubled, the apparent brightness is decreased by a factor of four.

True

When an electron in an atom goes from a higher energy state to a lower energy state, the atom A. emits a photon of a specific frequency B. absorbs a photon of a specific frequency C. absorbs several photons of a specific frequency D. can emit a photon of any frequency E. can absorb a photon of any frequency

emits a photon of a specific frequency

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

filtering to look at just a single color from an object

A stars luminosity is the A. apparent brightness of the star in our sky B. surface temperature of the star C. lifetime of the star D. total amount of light that the star will radiate over its entire lifetime E. total amount of light that the star radiates each second

total amount of light that the star radiates each second

When an atom loses an electron, it becomes A. sublimated B. dissociated C. ionized D. an isotope E. a plasma

ionized

From lowest energy to highest energy, which of the following correctly orders the different categories of electromagnetic radiation? A. inferred, visible light, ultraviolet, X rats, gamma rays, radio B. radio, infrared, visible light, ultraviolet, X rays, gamma rays C. visible light, infrared, X rays, ultraviolet, gamma rays, radio D. gamma rays, X rays, visible light, ultraviolet, infrared, gamma rays

radio, inferred, visible light, ultraviolet, X rays, gamma rays

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

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

Which of the following terms is given to a pair of stars that we can determine are orbiting each other only by measuring their periodic Doppler shifts? A. visual binary B. eclipsing binary C. spectroscopic binary D. double star E. none of the above

spectroscopic binary

Which of the following terms is given to a pair of stars that appear to change positions in the sky, indicating that they are orbiting one another? A. visual binary B. eclipsing binary C. spectroscopic binary D. double star E. none of the above

visual binary