Astronomy Exam 2
Currently, the largest optical telescope mirrors have a diameter of A) 1 m. B) 2 m. C) 5 m. D) 10 m. E) 100 m.
10 m.
An atom of the element iron has an atomic number of 26 and an atomic weight of 56. If it is neutral, how many protons, neutrons, and electrons does it have? A) 26 protons, 30 neutrons, 26 electrons B) 26 protons, 30 neutrons, 30 electrons C) 26 protons, 56 neutrons, 26 electrons D) 13 protons, 43 neutrons, 13 electrons E) 13 protons, 56 neutrons, 13 electrons
26 protons, 30 neutrons, 26 electrons
If you have a 100-watt light bulb, how much energy does it use each minute? A) 6,000 joules B) 6,000 watts C) 600 joules D) 600 watts E) 100 joules
6,000 joules
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 about thermal radiation is always true? A) A hot object emits more X rays than a cool object. B) A hot object emits more radio waves than a cool object. C) A hot object emits more total radiation than a cool object. D) A hot object emits more total radiation per unit surface area than a cool object. E) A hot object emits less total radiation than a cool object.
A hot object emits more total radiation per unit surface area than a cool object.
Which of the following statements about thermal radiation is always true? A) A hot object emits photons with a longer wavelength than a cool object. B) A hot object emits photons with a higher average energy than a cool object. C) A hot object emits more radio waves than a cool object. D) A hot object emits more X rays than a cool object.
A hot object emits photons with a higher average energy than a cool object.
How does the spectrum of a molecule differ from the spectrum of an atom? A) A molecule does not have spectral lines due to electrons changing energy levels. B) A molecule has additional spectral lines due to changes in its rotational and vibrational energies. C) Molecules only have spectral lines at ultraviolet wavelengths. D) Most atoms only have spectral lines at infrared wavelengths. E) An atom has a wider range of spectral lines than molecules.
A molecule has additional spectral lines due to changes in its rotational and vibrational energies.
Which of the following statements about electrical charge is true? A) Two negative charges will attract each other. B) Two positive charges will attract each other. C) A positive charge and a negative charge will repel each other. D) A positive charge and a negative charge will attract each other.
A positive charge and a negative charge will attract each other.
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.
When an atom absorbs a photon containing energy, any of the following can happen except which? A) The atom becomes excited. B) The atom is ionized. C) An electron moves from an upper energy level to a lower one. D) An electron moves from a lower energy level to an upper one.
An electron moves from an upper energy level to a lower one.
26) Each of the following describes an "Atom 1" and an "Atom 2." In which case are the two atoms isotopes of each other? A) Atom 1: nucleus with 6 protons and 8 neutrons, surrounded by 6 electrons Atom 2: nucleus with 7 protons and 8 neutrons, surrounded by 7 electrons B) Atom 1: nucleus with 8 protons and 8 neutrons, surrounded by 8 electrons Atom 2: nucleus with 8 protons and 8 neutrons, surrounded by 7 electrons C) Atom 1: nucleus with 92 protons and 143 neutrons, surrounded by 92 electrons Atom 2: nucleus with 92 protons and 146 neutrons, surrounded by 92 electrons D) Atom 1: nucleus with 1 proton and 0 neutrons, surrounded by 1 electron Atom 2: nucleus with 2 protons and 2 neutrons, surrounded by 2 electrons E) Atom 1: nucleus with 4 protons and 5 neutrons, surrounded by 4 electrons Atom 2: nucleus with 5 protons and 5 neutrons, surrounded by 4 electrons
Atom 1: nucleus with 92 protons and 143 neutrons, surrounded by 92 electrons Atom 2: nucleus with 92 protons and 146 neutrons, surrounded by 92 electrons
Which of the following is a principal advantage of CCDs over photographic film? A) CCDs allow long exposures (e.g., minutes or hours), and film does not. B) CCDs can record the colors of astronomical objects accurately, while film cannot. C) CCDs capture a much higher percentage of the incoming photons than does film. D) Images recorded with CCDs never require any image processing, while images recorded by film often do. E) CCDs can be attached to modern telescopes more easily than cameras.
CCDs capture a much higher percentage of the incoming photons than does film.
The largest effective telescope, created by radio interferometry, is the size of A) several football fields, in a natural depression in Puerto Rico. B) tens of miles across, in the deserts of New Mexico. C) the state of New Mexico. D) the continental United States. E) Earth.
Earth.
Which of the following statements about electrons is not true? A) Electrons orbit the nucleus rather like planets orbiting the Sun. B) Within an atom, an electron can have only particular energies. C) Electrons can jump between energy levels in an atom only if they receive or give up an amount of energy equal to the difference in energy between the energy levels. D) An electron has a negative electrical charge. E) Electrons have very little mass compared to protons or neutrons.
Electrons orbit the nucleus rather like planets orbiting the Sun.
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 allows two or more small telescopes to achieve a larger light-collecting area than they would have independently. C) t is designed to prevent light pollution from interfering with astronomical observations. D) It reduces 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 does the technique of interferometry allow? A) It allows two or more telescopes to obtain a total light-collecting area much larger than the total light-collecting area of the individual telescopes. B) It allows two or more telescopes to obtain the angular resolution of a single telescope much larger than any of the individual telescopes. C) It allows us to determine the chemical composition of stars. D) It allows astronomers to make astronomical observations without interference from light pollution. E) It allows the same telescope to make images with both radio waves and visible light.
It allows two or more telescopes to obtain the angular resolution of a single telescope much larger than any of the individual telescopes.
What is meant by spectral resolution? A) It is a measure of how much energy an object emits in different parts of the electromagnetic spectrum. B) It is a measure of how close two spectral lines can be distinguished. C) It is a measure of how close two point sources can be distinguished. D) It is the same as angular resolution when applied to telescopes operating at different wavelengths.
It is a measure of how close two spectral lines can be distinguished.
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 kind of instrument that can be hooked up to a telescope. D) It is a unit used 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 bad weather. E) Observers on the ground can use it at any time of day (i.e., not only during their night).
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.
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.
What do we mean by the diffraction limit of a telescope? A) It is the maximum size to which any telescope can be built. B) It describes the farthest distance to which the telescope can see. C) It describes the maximum exposure time for images captured with the telescope. D) It is the best angular resolution the telescope could achieve with perfect optical quality and in the absence of atmospheric distortion.
It is the best angular resolution the telescope could achieve with perfect optical quality and in the absence of atmospheric distortion.
Which of the following best describes what we mean by the focal plane of a telescope? A) It is the upper surface of the telescope's primary lens or mirror. B) 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. C) It is the lower surface of the telescope's primary lens or mirror. D) 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.
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.
Oxygen has atomic number 8. How many times must an oxygen atom be ionized to create an O+5 ion, and how many electrons will the ion have? A) It must be ionized three times; it now has five electrons. B) It must be ionized five times; it now has five electrons. C) It must be ionized five times; it now has three electrons. D) It doesn't have to be ionized; it just needs to gain five protons. E) It doesn't have to be ionized; it already has only three electrons.
It must be ionized five times; it now has three electrons.
How can an electron in an atom lose energy to go from a higher energy level to a lower energy level? A) It loses kinetic energy. B) It releases a photon equal in energy to its own energy drop. C) It absorbs a photon equal in energy to its own energy drop. D) It loses gravitational potential energy. E) It exchanges gravitational potential energy for kinetic energy.
It releases a photon equal in energy to its own energy drop.
What do astronomers mean by light pollution? A) Light pollution is a type of air pollution created by lightweight gases 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 chemicals 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.
What do astronomers mean by light pollution? A) Light pollution refers to pollution caused by light industry as opposed to heavy industry. B) Light pollution refers to harmful gases emitted by common street lights. C) Light pollution refers to light used for human activities that brightens the sky and hinders astronomical observations. D) Light pollution refers to the lights that must be used inside major observatories and that make it difficult for astronomers' eyes to adapt to darkness. E) Light pollution is another name for sunlight, which makes it impossible to see stars in the daytime.
Light pollution refers to light used for human activities that brightens the sky and hinders astronomical observations.
10) 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.
14) Which of the following statements about X rays and radio waves is not true? A) Neither X rays nor radio waves can penetrate the earth's atmosphere. B) X rays have shorter wavelengths than radio waves. C) X rays and radio waves are both forms of light, or electromagnetic radiation. D) X rays have higher frequency than radio waves. E) X rays have higher energy than radio waves.
Neither X rays nor radio waves can penetrate the earth's atmosphere.
Why do astronomers need different telescope designs to observe across the electromagnetic spectrum? A) New telescopes incorporate new technology to increase their efficiency. B) Telescopes have to adapt to the greater distortion of the atmosphere at shorter wavelengths. C) Photons of different energy behave differently and require different collection strategies. D) Light pollution is worse at radio wavelengths than visible wavelengths. E) Astronomers and engineers enjoy the challenge of making new telescope designs.
Photons of different energy behave differently and require different collection strategies.
Which of the following statements best describes the two principal advantages of telescopes over eyes? A) Telescopes can collect far more light with far better angular resolution. B) Telescopes can collect far 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.
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 can collect far more light with far greater magnification. C) Telescopes collect more light and are unaffected by twinkling. D) Telescopes have much more magnification and better angular resolution.
Telescopes can collect far more light with far better angular resolution.
Consider an atom of gold in which the nucleus contains 79 protons and 118 neutrons. What is its atomic number and atomic weight? A) The atomic number is 79, and the atomic weight is 197. B) The atomic number is 79, and the atomic weight is 118. C) The atomic number is 118, and the atomic weight is 197. D) The atomic number is 118, and the atomic weight is 79.
The atomic number is 79, and the atomic weight is 197.
Suppose you see two stars: a blue star and a red star. Which of the following can you conclude about the two stars? Assume that no Doppler shifts are involved. (Hint: Think about the laws of thermal radiation.) A) The red star is more massive than the blue star. B) The blue star is more massive than the red star. C) The blue star is farther away than the red star. D) The blue star has a hotter surface temperature than the red star. E) The red star has a hotter surface temperature than the blue star.
The blue star has a hotter surface temperature than the red star.
Which of the following statements about light focusing is not true? A) In a healthy eye, light is focused on the retina. B) Film should be placed at the focal plane in a camera. C) If you try to look at an image that is not formed at the focal plane, it will be blurry. D) The focal plane of a reflecting telescope is always located within a few inches of the primary mirror. E) Light can be focused with a lens or a mirror.
The focal plane of a reflecting telescope is always located within a few inches of the primary mirror.
You observe a distant galaxy. You find that a spectral line normally found in the visible part of the spectrum is shifted toward the infrared. What do you conclude? A) The galaxy is moving away from you. B) The galaxy is moving toward you. C) The galaxy has very weak gravity. D) The galaxy is made purely of hydrogen. E) The composition of the galaxy is changing.
The galaxy is moving away from you.
Consider an atom of gold in which the nucleus contains 79 protons and 118 neutrons. If it is doubly ionized, what is the charge of the gold ion and how many electrons remain in the ion? A) The gold ion has a charge of +2 and 77 electrons. B) The gold ion has a charge of +2 and 79 electrons. C) The gold ion has a charge of -2 and 77 electrons. D) The gold ion has a charge of +2 and 2 electrons. E) The gold ion has a charge of +79 and no electrons.
The gold ion has a charge of +2 and 77 electrons.
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 spectral 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.
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 while the other one becomes fuzzy (grainy) looking. Which of the following statements is true? A) The one that still looks sharp at large size has better (smaller) angular resolution than the one that looks fuzzy. B) The one that looks fuzzy at large size has better angular resolution (smaller) than the one that looks sharp. C) Both photographs have the same angular resolution, because they were both printed at the same sizes in each case. D) Both photographs have the same angular resolution, because they are both photographs of the same object.
The one that still looks sharp at large size has better (smaller) angular resolution than the one that looks fuzzy.
If one object has a large redshift and another object has a small redshift, what can we conclude about these two objects? A) The one with the large redshift is moving toward us faster than the one with the small redshift. B) The one with the large redshift is moving away from us, and the one with the small redshift is moving toward us. C) The one with the large redshift is moving away from us faster than the one with the small redshift. D) The one with the large redshift is hotter and therefore is putting out more radiation. E) The one with the large redshift is redder than the other one.
The one with the large redshift is moving away from us faster than the one with the small redshift.
If we observe one edge of a planet to be redshifted and the opposite edge to be blueshifted, what can we conclude about the planet? A) The planet is actually two bodies, one moving toward us, the other away from us. B) The planet is in the process of falling apart. C) The planet is in the process of formation. D) The planet is rotating. E) The planet's surface is very different from one side to the other.
The planet is rotating.
From laboratory measurements, we know that a particular spectral line formed by hydrogen appears at a wavelength of 121.6 nanometers (nm). The spectrum of a particular star shows the same hydrogen line appearing 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" actually is a planet.
The star is moving away from us.
From laboratory measurements, we know that a particular spectral line formed by hydrogen appears at a wavelength of 486.1 nanometers (nm). The spectrum of a particular star shows the same hydrogen line appearing at a wavelength of 485.9 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" actually is a planet.
The star is moving toward us.
18) What is a compound? A) a group of molecules B) a molecule containing hydrogen C) a molecule containing two or more elements D) an ionized molecule E) a molecule containing carbon
a molecule containing two or more elements
We can learn a lot about the properties of a star by studying its spectrum. All of the following statements are true except one. Which one? 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.
Suppose the angular separation of two stars is smaller than the angular resolution of your eyes. How will the stars appear to your eyes? A) You will not be able to see these two stars at all. B) The two stars will look like a single point of light. C) The two stars will appear to be touching, looking rather like a small dumbbell. D) You will see two distinct stars. E) You will see only the larger of the two stars, not the smaller one.
The two stars will look like a single point of light.
Which of the following is always true about images captured with X-ray telescopes? A) They are always very pretty. B) They are always displayed with the highest possible angular resolution. C) They are always useful for seeing through things. D) They are always displayed in false color. E) They are always displayed with north pointing upward in the images.
They are always displayed in false color.
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.
At extremely high temperatures (e.g., millions of degrees), which of the following best describes the phase of matter? A) a gas of rapidly moving molecules B) a plasma consisting of positively charged ions and free electrons C) a gas consisting of individual, neutral atoms, but no molecules D) a plasma consisting of rapidly moving, neutral atoms E) none of the above (At these extremely high temperatures, matter cannot exist.)
a plasma consisting of positively charged ions and free electrons
13) Which of the following statements about X rays and radio waves is not true? A) X rays have shorter wavelengths than radio waves. B) X rays and radio waves are both forms of light, or electromagnetic radiation. C) X rays have higher frequency than radio waves. D) X rays have higher energy than radio waves. E) X rays travel through space faster than radio waves.
X rays travel through space faster than radio waves.
What is an artificial star? A) a point of light in Earth's atmosphere created by a laser for the purpose of monitoring atmospheric fluctuations B) a satellite orbiting Earth C) a meteor D) a possible source of dark matter in the universe E) the unseen member of a binary star system
a point of light in Earth's atmosphere created by a laser for the purpose of monitoring atmospheric fluctuations
20) How much electrical charge does an atom with 6 protons, 6 neutrons, and 5 electrons have? A) a total charge of +17 B) a negative charge of -5 C) a positive charge of +7 D) a positive charge of +1 E) none of the above
a positive charge of +1
A perfectly opaque object that absorbs all radiation and reemits the absorbed energy as thermal radiation is A) a hot, dense cloud of gas. B) a cold, dense cloud of gas. C) an infrared radiation emitter. D) a thermal emitter. E) transparent.
a thermal emitter.
Compared to the volume of its nucleus, the volume of an atom is about A) the same. B) a thousand times greater. C) a million times greater. D) a billion times greater. E) a trillion times greater.
a trillion times greater.
8) The frequency of a wave is A) the number of peaks passing by any point each second. B) measured in cycles per second. C) measured in hertz (Hz). D) equal to the speed of the wave divided by the wavelength of the wave. E) all of the above
all of the above
What is the angular resolution of the human eye? A) about 1 degree B) about 1 arcsecond (1/3600 of a degree) C) about 1 arcminute, or 1/60 of a degree D) about 1 milliarcsecond
about 1 arcminute, or 1/60 of a degree
If a material is highly opaque, then it A) reflects most light. B) absorbs most light. C) transmits most light. D) scatters most light. E) emits most light.
absorbs most light.
When white light passes through a cool cloud of gas, we see A) visible light. B) infrared light. C) thermal radiation. D) an absorption line spectrum. E) an emission line spectrum.
an absorption line spectrum.
An electron-volt is A) the charge of one electron. B) the energy of one electron. C) the energy jump between the first and second energy levels of hydrogen. D) an amount of energy much smaller than a joule. E) an amount of energy much larger than a joule.
an amount of energy much smaller than a joule.
39) If you heat a gas so that collisions are continually bumping electrons to higher energy levels, when the electrons fall back to lower energy levels the gas produces A) thermal radiation. B) an absorption line spectrum. C) an emission line spectrum. D) X rays. E) radio waves.
an emission line spectrum.
When light reflects off an object, what is the relation between the angle of incidence and the angle of reflection? A) angle of incidence = angle of reflection B) angle of incidence + angle of reflection = 90° C) angle of incidence + angle of reflection = 180° D) angle of incidence - angle of reflection = 90° E) It depends on the material that the light reflects off.
angle of incidence = angle of reflection
What causes stars to twinkle? A) It is intrinsic to the stars-their brightness varies as they expand and contract. B) variations in the absorption of the atmosphere C) variable absorption by interstellar gas along the line of sight to the star D) bending of light rays by turbulent layers in the atmosphere E) the inability of the human eye to see faint objects
bending of light rays by turbulent layers in the atmosphere
Which of the following wavelength regions cannot be studied with telescopes on the ground? A) radio waves B) ultraviolet C) X rays D) both B and C E) both A and C
both B and C
An atom in an excited state contains more of what type of energy than the same atom in the ground state? A) mass-energy B) kinetic energy C) thermal energy D) gravitational potential energy E) electric potential energy
electric potential energy
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.
Telescopes operating at this wavelength must be cooled to observe faint astronomical objects. A) radio B) extreme infrared C) visible D) X-ray E) gamma-ray
extreme infrared
Order the following in order of increasing efficiency of detecting photons of visible light. A) eye, photographic film, CCD B) photographic film, CCD, eye C) CCD, eye, photographic film D) CCD, photographic film, eye E) eye, CCD, photographic film
eye, photographic film, CCD
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
12) From shortest to longest wavelength, which of the following correctly orders the different categories of electromagnetic radiation? A) infrared, visible light, ultraviolet, X rays, 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, ultraviolet, visible light, infrared, radio E) gamma rays, X rays, visible light, ultraviolet, infrared, radio
gamma rays, X rays, ultraviolet, visible light, infrared, radio
Spectra from neutral atoms compared with spectra from ionized atoms of the same element A) are the same. B) are slightly redshifted. C) are slightly blueshifted. D) have different sets of spectral lines. E) have the same sets of spectral lines but different widths for those lines.
have different sets of spectral lines.
The spectra of most galaxies show redshifts. This means that their spectral lines A) always are in the red part of the visible spectrum. B) have wavelengths that are longer than normal. C) have wavelengths that are shorter than normal. D) have a higher intensity in the red part of the spectrum. E) have normal wavelengths, but absorption of light makes them appear red.
have wavelengths that are longer than normal.
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 angular resolution B) high turbulence C) a radio telescope D) high spectral resolution
high spectral resolution
Which of the following objects is not a close approximation of a thermal emitter? A) hot, thin gas B) a star C) a filament in a light bulb D) you E) a planet
hot, thin gas
When an atom loses an electron, it becomes A) sublimated. B) dissociated. C) ionized. D) an isotope. E) a plasma.
ionized
The loss of an electron from a neutral helium atom results in A) neutral hydrogen. B) ionized hydrogen. C) ionized helium. D) neutral deuterium. E) ionized deuterium.
ionized helium.
5) Grass (that is healthy) looks green because A) it emits green light and absorbs other colors. B) it absorbs green light and emits other colors. C) it transmits green light and emits other colors. D) it reflects green light and absorbs other colors.
it reflects green light and absorbs other colors.
17) How many atoms fit across the period at the end of this sentence? A) hundreds B) thousands C) millions D) billions E) more than you could count in a lifetime
millions
Sublimation is the process in which A) molecules go from the solid phase to the liquid phase. B) molecules go from the liquid phase to the gas phase. C) molecules go from the solid phase to the gas phase. D) electrons are stripped from atoms. E) electrons are captured by ions.
molecules go from the solid phase to the gas phase.
A gas heated to millions of degrees would emit A) mostly radio waves. B) mostly X rays. C) mostly ultraviolet light. D) an equal amount of all wavelengths of light. E) no light, because it is too hot.
mostly X rays.
The study of energy levels in atoms is called A) special relativity. B) general relativity. C) quantum mechanics. D) classical mechanics. E) particle physics.
quantum mechanics.
7) Which of the following cannot be described by a field? A) gravitational forces B) electrical forces C) magnetic forces D) radiation pressure
radiation pressure
Thermal radiation is defined as A) radiation produced by a hot object. B) radiation in the infrared part of the spectrum. C) radiation that depends only on the emitting object's temperature. D) radiation in the form of emission lines from an object. E) radiation that is felt as heat.
radiation that depends only on the emitting object's temperature.
At which wavelength range is there no current or planned space observatory? A) radio B) infrared C) visible D) X-ray E) gamma-ray
radio
In what part of the electromagnetic spectrum do the biggest telescopes on Earth operate? A) radio B) infrared C) visible D) ultraviolet E) X-ray
radio
In what wavelength range was interferometry first routinely used? A) radio B) infrared C) optical D) ultraviolet E) X-ray
radio
11) From lowest energy to highest energy, which of the following correctly orders the different categories of electromagnetic radiation? A) infrared, visible light, ultraviolet, X rays, 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, radio E) radio, X rays, visible light, ultraviolet, infrared, gamma rays
radio, infrared, 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 and ultraviolet regions B) all light with wavelengths longer than ultraviolet wavelengths C) all light with wavelengths shorter than infrared wavelengths D) infrared, visible, and ultraviolet light
radio, visible, and very limited portions of the infrared and ultraviolet regions
We can see each other in the classroom right now because we A) emit thermal radiation. B) emit visible light. C) emit infrared light. D) reflect visible light. E) reflect infrared light.
reflect visible light.
Without telescopes or other aid, we can look up and see the Moon in the night sky because it A) emits visible light. B) emits thermal radiation. C) reflects infrared light. D) reflects visible light. E) glows through radioactive decay.
reflects visible light.
Suppose you built a scale-model atom in which the nucleus was the size of a tennis ball. About how far would the cloud of electrons extend? A) several centimeters B) a few meters C) a few tens of meters D) several kilometers E) to the Sun
several kilometers
Which of the following studies is best suited to a time monitoring experiment? A) studying how different stars differ in their chemical compositions B) studying whether a particular star's brightness is steady or variable C) determining the age of the solar system D) measuring the rotation rate of a distant star E) estimating the time since the Big Bang
studying whether a particular star's brightness is steady or variable
What does angular resolution measure? A) the angular size of the smallest features that the telescope can see B) the brightness of an image C) the size of an image D) the number of electromagnetic waves captured by an image
the angular size of the smallest features that the telescope can see
Dissociation is the process in which A) the bonds between atoms in a molecule are broken. B) a molecule goes from the solid phase to the gas phase. C) the bonds between electrons around an atomic nucleus are broken. D) an element changes into another form. E) an electron is shared between atomic nuclei.
the bonds between atoms in a molecule are broken.
9) The wavelength of a wave is A) how strong the wave is. B) the distance between a peak of the wave and the next trough. C) the distance between two adjacent peaks of the wave. D) the distance between where the wave is emitted and where it is absorbed. E) equal to the speed of the wave times the wave's frequency.
the distance between two adjacent peaks of the wave.
6) Everything looks red through a red filter because A) the filter emits red light and absorbs other colors. B) the filter absorbs red light and emits other colors. C) the filter transmits red light and absorbs other colors. D) the filter reflects red light and transmits other colors.
the filter transmits red light and absorbs other colors.
Which of the following could not be measured by an observation that uses only imaging? A) the rate at which a variable star brightens and dims B) the general shape of an interstellar cloud of gas C) the color of a planet D) the brightness of a star in our sky E) the number of bright stars in a nearby star cluster
the rate at which a variable star brightens and dims
Which of the following could not be determined by an observation that uses only spectroscopy? A) the chemical composition of a distant star B) the speed at which a distant galaxy is moving away from us C) the surface temperature of a distant star D) the rotation rate of a distant star E) the size of a distant galaxy
the size of a distant galaxy
Which of the following is not a good reason to place observatories on remote mountain tops? A) to reduce light pollution B) to reduce light distortion C) to reduce light absorption D) to be able to observe at radio wavelengths E) to be able to observe at infrared wavelengths
to be able to observe at radio wavelengths
What is the purpose of adaptive optics? A) to improve the angular resolution of telescopes in space B) to eliminate the distorting effects of atmospheric turbulence for telescopes on the ground C) to increase the collecting area of telescopes on the ground D) to increase the magnification of telescopes on the ground E) to allow several small telescopes to work together like a single larger telescope
to eliminate the distorting effects of atmospheric turbulence for telescopes on the ground
If a material is transparent, then it A) reflects light well. B) absorbs light well. C) transmits light well. D) scatters light well. E) emits light well.
transmits light well.
Which of the following effects is caused by atmospheric turbulence? A) twinkling of stars B) light pollution C) magnification of images D) diffraction of light
twinkling of stars