Astronomy Mastering Astronomy Chapters 5 And 7

24 July 2022
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question
Your electric utility bill probably shows your energy use for the month in units of kilowatt-hours. A kilowatt-hour is defined as the energy used in 1 hour at a rate of 1 kilowatt (1,000 watts); that is, 1 kilowatt-hour = 1 kilowatt × 1 hour. Use this fact to convert 1 kilowatt-hour into joules.
answer
3.60×10ˆ6 J
question
Your electric utility bill probably shows your energy use for the month in units of kilowatt-hours. A kilowatt-hour is defined as the energy used in 1 hour at a rate of 1 kilowatt (1,000 watts); that is, 1 kilowatt-hour = 1 kilowatt × 1 hour. If your bill says you used 800 kilowatt-hours, how much energy did you use in joules?
answer
2.88×10ˆ9 J
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What is the wavelength of a radio photon from an "AM" radio station that broadcasts at 1140 kilohertz?
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λ = 260m
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What is its energy?
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E = 7.6×10ˆ−28 J
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Choose the correct definition of an atom's atomic number. An atom's atomic number is the number of neutrons it has in its nucleus. An atom's atomic number is the number of particles it has in its nucleus. An atom's atomic number is the number of protons it has in its nucleus. An atom's atomic number is the number of electrons it has in its nucleus.
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An atom's atomic number is the number of protons it has in its nucleus.
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Choose the correct definition of an atom's atomic mass number. An atom's atomic mass number is the number of protons plus the number of neutrons. An atom's atomic mass number is the number of protons plus the number of electrons. An atom's atomic mass number is the number of electrons plus the number of neutrons. An atom's atomic mass number is the number of particles.
answer
An atom's atomic mass number is the number of protons plus the number of neutrons.
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Choose the correct conditions, under which two atoms are different isotopes of the same element. Two atoms having the same number of neutrons and different numbers of protons. Two atoms having the same number of protons and different numbers of electrons. Two atoms having the same number of protons and different numbers of neutrons. Two atoms having the same number of electrons and different numbers of protons.
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Two atoms having the same number of protons and different numbers of neutrons.
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Choose the correct definition of a molecule.
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A molecule is a group of two or more atoms bound together.
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A spectral line that appears at a wavelength of 321 nm in the laboratory appears at a wavelength of 328 nm in the spectrum of a distant object. We say that the object's spectrum is: redshifted. blueshifted. whiteshifted.
answer
redshifted.
question
Which of the following best describes why the Sun's spectrum contains black lines over an underlying rainbow? The Sun produces a continuous rainbow of color, while the black lines are caused by imperfections in the instruments used to record the spectrum. The Sun's hot interior produces a continuous rainbow of color, but cooler gas at the surface absorbs light at particular wavelengths. The rainbow colors represent emission by particular chemical elements, while the black lines represent gaps where no element can emit light. The Sun produces a continuous rainbow of color, while the black lines are caused by atoms and molecules in Earth's atmosphere.
answer
The Sun's hot interior produces a continuous rainbow of color, but cooler gas at the surface absorbs light at particular wavelengths.
question
Notice that the Sun's spectrum appears brightest (or most intense) in the yellow-green region. This fact tells us __________. the approximate temperature of the Sun's surface the chemical composition of the Sun that the Sun should appear yellow-green to our eyes that the Sun's surface consists of a layer of cooler gas above a hotter interior
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the approximate temperature of the Sun's surface One of the two laws of thermal radiation (Wien's law) states that the peak wavelength of a spectrum is directly related to an object's temperature. A peak at yellow-green wavelengths corresponds to a temperature of about 5800 K.
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Suppose we want to know what the Sun is made of. What should we do? Count the total number of black lines in the Sun's spectrum. Precisely measure the intensity of light in each of the black lines in the spectrum. Compare the wavelengths of lines in the Sun's spectrum to the wavelengths of lines produced by chemical elements in the laboratory. Find the precise wavelength at which the background rainbow of color peaks in brightness.
answer
Compare the wavelengths of lines in the Sun's spectrum to the wavelengths of lines produced by chemical elements in the laboratory.
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If you have a 100-watt light bulb, how much energy does it use each minute? 6,000 watts 600 watts 100 joules 600 joules 6,000 joules
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6,000 joules
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If a material is highly opaque, then it reflects most light. scatters most light. emits most light. absorbs most light. transmits most light.
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absorbs most light.
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When light reflects off an object, what is the relation between the angle of incidence and the angle of reflection? angle of incidence - angle of reflection = 90° angle of incidence + angle of reflection = 90° angle of incidence = angle of reflection angle of incidence + angle of reflection = 180° It depends on the material that the light reflects off.
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angle of incidence = angle of reflection (like a mirror)
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If a material is transparent, then it transmits light well. absorbs light well. emits light well. scatters light well. reflects light well.
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transmits light well.
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Everything looks red through a red filter because the filter absorbs red light and emits other colors. the filter reflects red light and transmits other colors. the filter transmits red light and absorbs other colors. the filter emits red light and absorbs other colors.
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the filter transmits red light and absorbs other colors.
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Energy and power are different words for the same thing. True False
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False
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Grass is green because it absorbs green light, reflecting all other colors. True False
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False
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Grass appears green because it transmits green light and emits other colors. it reflects green light and absorbs other colors. it absorbs green light and emits other colors. it emits green light and absorbs other colors.
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it reflects green light and absorbs other colors.
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Which of the following cannot be described by a field? gravitational forces electrical forces radiation pressure magnetic forces
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radiation pressure
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The frequency of a wave is measured in cycles per second. measured in hertz (Hz). equal to the speed of the wave divided by the wavelength of the wave. the number of peaks passing by any point each second. all of the above
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all of the above
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The wavelength of a wave is the distance between where the wave is emitted and where it is absorbed. how strong the wave is. the distance between two adjacent peaks of the wave. equal to the speed of the wave times the wave's frequency. the distance between a peak of the wave and the next trough.
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the distance between two adjacent peaks of the wave.
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How are wavelength, frequency, and energy related for photons of light? Longer wavelength means higher frequency and higher energy. Longer wavelength means lower frequency and lower energy. Longer wavelength means higher frequency and lower energy. There is no simple relationship because different photons travel at different speeds. Longer wavelength means lower frequency and higher energy.
answer
Longer wavelength means lower frequency and lower energy.
question
From lowest energy to highest energy, which of the following correctly orders the different categories of electromagnetic radiation? radio, X rays, visible light, ultraviolet, infrared, gamma rays gamma rays, X rays, visible light, ultraviolet, infrared, radio infrared, visible light, ultraviolet, X rays, gamma rays, radio visible light, infrared, X rays, ultraviolet, gamma rays, radio radio, infrared, visible light, ultraviolet, X rays, gamma rays
answer
radio, infrared, visible light, ultraviolet, X rays, gamma rays
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From shortest to longest wavelength, which of the following correctly orders the different categories of electromagnetic radiation? gamma rays, X rays, ultraviolet, visible light, infrared, radio infrared, visible light, ultraviolet, X rays, gamma rays, radio radio, infrared, visible light, ultraviolet, X rays, gamma rays gamma rays, X rays, visible light, ultraviolet, infrared, radio visible light, infrared, X rays, ultraviolet, gamma rays, radio
answer
gamma rays, X rays, ultraviolet, visible light, infrared, radio
question
Which of the following statements about X rays and radio waves is not true? X rays and radio waves are both forms of light, or electromagnetic radiation. X rays travel through space faster than radio waves. X rays have higher frequency than radio waves. X rays have shorter wavelengths than radio waves. X rays have higher energy than radio waves.
answer
X rays travel through space faster than radio waves.
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Which of the following statements about X rays and radio waves is not true? X rays have higher frequency than radio waves. X rays and radio waves are both forms of light, or electromagnetic radiation. Neither X rays nor radio waves can penetrate the earth's atmosphere. X rays have higher energy than radio waves. X rays have shorter wavelengths than radio waves.
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Neither X rays nor radio waves can penetrate the earth's atmosphere.
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We can see each other in the classroom right now because we emit infrared light. reflect visible light. reflect infrared light. emit visible light. emit thermal radiation.
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reflect visible light.
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The shorter the wavelength of light, the higher its frequency. True False
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True
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The greater the wavelength of light, the greater its energy. True False
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False
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X rays, because they have more energy, travel through space faster than visible light. True False
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False
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You are currently emitting electromagnetic waves. True False
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True
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X-rays always have more energy than radio waves. True False
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True
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How many atoms fit across the period at the end of this sentence? hundreds billions thousands millions more than you could count in a lifetime
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millions
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What is a compound? an ionized molecule a molecule containing two or more elements a group of molecules a molecule containing hydrogen a molecule containing carbon
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a molecule containing two or more elements
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Compared to the volume of its nucleus, the volume of an atom is about a billion times greater. a million times greater. a trillion times greater. a thousand times greater. the same.
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a trillion times greater.
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How much electrical charge does an atom with 6 protons, 6 neutrons, and 5 electrons have? a total charge of +17 a negative charge of -5 a positive charge of +1 a positive charge of +7 none of the above
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a positive charge of +1
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Which of the following statements about electrical charge is true? Two positive charges will attract each other. Two negative charges will attract each other. A positive charge and a negative charge will attract each other. A positive charge and a negative charge will repel each other.
answer
A positive charge and a negative charge will attract each other.
question
Which of the following statements about electrons is not true? Within an atom, an electron can have only particular energies. 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. An electron has a negative electrical charge. Electrons have very little mass compared to protons or neutrons. Electrons orbit the nucleus rather like planets orbiting the Sun.
answer
Electrons orbit the nucleus rather like planets orbiting the Sun.
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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? to the Sun a few meters a few tens of meters several centimeters several kilometers
answer
several kilometers
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Consider an atom of gold in which the nucleus contains 79 protons and 118 neutrons. What is its atomic number and atomic weight? The atomic number is 118, and the atomic weight is 197. The atomic number is 118, and the atomic weight is 79. The atomic number is 79, and the atomic weight is 118. The atomic number is 79, and the atomic weight is 197.
answer
The atomic number is 79, and the atomic weight is 197.
question
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? The gold ion has a charge of +2 and 79 electrons. The gold ion has a charge of +2 and 77 electrons. The gold ion has a charge of -2 and 77 electrons. The gold ion has a charge of +2 and 2 electrons. The gold ion has a charge of +79 and no electrons.
answer
The gold ion has a charge of +2 and 77 electrons.
question
Each of the following describes an "Atom 1" and an "Atom 2." In which case are the two atoms isotopes of each other? 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 1 proton and 0 neutrons, surrounded by 1 electron Atom 2: nucleus with 2 protons and 2 neutrons, surrounded by 2 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 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 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
answer
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
question
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? 13 protons, 56 neutrons, 13 electrons 26 protons, 30 neutrons, 30 electrons 26 protons, 56 neutrons, 26 electrons 13 protons, 43 neutrons, 13 electrons 26 protons, 30 neutrons, 26 electrons
answer
26 protons, 30 neutrons, 26 electrons
question
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? It must be ionized five times; it now has three electrons. It doesn't have to be ionized; it just needs to gain five protons. It must be ionized three times; it now has five electrons. It must be ionized five times; it now has five electrons. It doesn't have to be ionized; it already has only three electrons.
answer
It must be ionized five times; it now has three electrons.
question
At extremely high temperatures (e.g., millions of degrees), which of the following best describes the phase of matter? a plasma consisting of rapidly moving, neutral atoms a gas consisting of individual, neutral atoms, but no molecules a gas of rapidly moving molecules a plasma consisting of positively charged ions and free electrons none of the above (At these extremely high temperatures, matter cannot exist.)
answer
a plasma consisting of positively charged ions and free electrons
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Dissociation is the process in which an element changes into another form. an electron is shared between atomic nuclei. a molecule goes from the solid phase to the gas phase. the bonds between atoms in a molecule are broken. the bonds between electrons around an atomic nucleus are broken.
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the bonds between atoms in a molecule are broken.
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An atom in an excited state contains more of what type of energy than the same atom in the ground state? electric potential energy thermal energy mass-energy gravitational potential energy kinetic energy
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electric potential energy
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When an atom absorbs a photon containing energy, any of the following can happen except which? The atom is ionized. An electron moves from an upper energy level to a lower one. An electron moves from a lower energy level to an upper one. The atom becomes excited.
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An electron moves from an upper energy level to a lower one.
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The loss of an electron from a neutral helium atom results in ionized deuterium. neutral hydrogen. ionized helium. neutral deuterium. ionized hydrogen
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ionized helium.
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An electron-volt is the energy jump between the first and second energy levels of hydrogen. the charge of one electron. the energy of one electron. an amount of energy much larger than a joule. an amount of energy much smaller than a joule.
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an amount of energy much smaller than a joule.
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The study of energy levels in atoms is called quantum mechanics. special relativity. classical mechanics. particle physics. general relativity.
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quantum mechanics.
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How can an electron in an atom lose energy to go from a higher energy level to a lower energy level? It absorbs a photon equal in energy to its own energy drop. It loses kinetic energy. It loses gravitational potential energy. It releases a photon equal in energy to its own energy drop. It exchanges gravitational potential energy for kinetic energy.
answer
It releases a photon equal in energy to its own energy drop.
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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 thermal radiation. radio waves. an absorption line spectrum. an emission line spectrum. X rays.
answer
an emission line spectrum.
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When an electron in an atom goes from a higher energy state to a lower energy state, the atom can absorb a photon of any frequency. absorbs a photon of a specific frequency. emits a photon of a specific frequency. can emit a photon of any frequency. absorbs several photons of a specific frequency.
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emits a photon of a specific frequency.
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There are more atoms in a glass of water than stars in the observable universe. True False
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True
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The atomic nuclei of the same element always have the same number of protons. True False
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True
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The atomic nuclei of the same element always have the same number of neutrons. True False
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False (isotops)
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The energy levels for electrons vary from one element to another. True False
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True
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The energy levels of an element and its ion are the same. True False
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False
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Without telescopes or other aid, we can see the Moon because it emits visible light. reflects infrared light. glows through radioactive decay. emits thermal radiation. reflects visible light.
answer
reflects visible light.
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Vaporization is the process in which molecules go from the liquid phase to the gas phase. molecules go from the solid phase to the liquid phase. electrons are stripped from atoms. electrons are captured by ions. molecules go from the solid phase to the gas phase.
answer
molecules go from the solid phase to the gas phase. Mastering Astronomy: wrong liquid to gas
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When an atom loses an electron, it becomes dissociated. a plasma. an isotope. vaporized.
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ionized
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When white light passes through a cool cloud of gas, we see an absorption line spectrum. thermal radiation. infrared light. an emission line spectrum. visible light.
answer
an absorption line spectrum.
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Spectra from neutral atoms compared with spectra from ionized atoms of the same element have the same sets of spectral lines but different widths for those lines. are slightly redshifted. have different sets of spectral lines. are slightly blueshifted. are the same.
answer
have different sets of spectral lines.
question
Which of the following objects is not a close approximation of a thermal emitter? hot, thin gas you a filament in a light bulb a star a planet
answer
hot, thin gas
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Thermal radiation is defined as radiation that depends only on the emitting object's temperature. radiation that is felt as heat. radiation produced by a hot object. radiation in the form of emission lines from an object. radiation in the infrared part of the spectrum.
answer
radiation that depends only on the emitting object's temperature.
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A perfectly opaque object that absorbs all radiation and reemits the absorbed energy as thermal radiation is a thermal emitter. transparent. a cold, dense cloud of gas. an infrared radiation emitter. a hot, dense cloud of gas.
answer
a thermal emitter.
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Which of the following statements about thermal radiation is always true? A hot object emits photons with a longer wavelength than a cool object. A hot object emits more X rays than a cool object. A hot object emits more radio waves than a cool object. A hot object emits photons with a higher average energy than a cool object.
answer
A hot object emits photons with a higher average energy than a cool object.
question
If two objects are the same size but one object is 3 times hotter than the other object, the hotter object emits 81 times more energy. 9 times more energy. 12 times more energy. 3 times more energy. none of the above
answer
81 times more energy.
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A gas heated to millions of degrees would emit mostly radio waves. mostly X rays. mostly ultraviolet light. an equal amount of all wavelengths of light. no light, because it is too hot
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mostly X rays.
question
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? We can identify chemical elements present in the star by recognizing patterns of spectral lines that correspond to particular chemicals. The total amount of light in the spectrum tells us the star's radius. We can look at Doppler shifts of spectral lines to determine the star's speed toward or away from us. The peak of the star's thermal emission tells us its temperature: Hotter stars peak at shorter (bluer) wavelengths.
answer
The total amount of light in the spectrum tells us the star's radius
question
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? The star is getting hotter. The star is getting colder. The star is moving away from us. The star is moving toward us. The "star" actually is a planet.
answer
The star is moving toward us.
question
How does the spectrum of a molecule differ from the spectrum of an atom? A molecule has additional spectral lines due to changes in its rotational and vibrational energies. A molecule does not have spectral lines due to electrons changing energy levels. Molecules only have spectral lines at ultraviolet wavelengths. An atom has a wider range of spectral lines than molecules. Most atoms only have spectral lines at infrared wavelengths.
answer
A molecule has additional spectral lines due to changes in its rotational and vibrational energies.
question
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? The galaxy is moving away from you. The galaxy is moving toward you. The composition of the galaxy is changing. The galaxy has very weak gravity. The galaxy is made purely of hydrogen.
answer
The galaxy is moving away from you.
question
If one object has a large redshift and another object has a small redshift, what can we conclude about these two objects? The one with the large redshift is moving away from us faster than the one with the small redshift. The one with the large redshift is moving toward us faster than the one with the small redshift. The one with the large redshift is hotter and therefore is putting out more radiation. The one with the large redshift is redder than the other one. The one with the large redshift is moving away from us, and the one with the small redshift is moving toward us.
answer
The one with the large redshift is moving away from us faster than the one with the small redshift.
question
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.) The red star has a hotter surface temperature than the blue star. The blue star is farther away than the red star. The blue star has a hotter surface temperature than the red star. The blue star is more massive than the red star. The red star is more massive than the blue star.
answer
The blue star has a hotter surface temperature than the red star.
question
Lines of a particular element appear at the same wavelength in both emission and absorption line spectra. True False
answer
True
question
Any object moving relative to Earth will have a Doppler shift. True False
answer
False
question
If we observe one edge of a star to be redshifted and the opposite edge to be blueshifted, what can we conclude about the star? The star is in the process of formation. The star is rotating. The star is in the process of falling apart. The star is actually two bodies, one moving toward us, the other away from us. The star's surface is very different from one side to the other.
answer
The star is rotating.
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Which planet? ...has a rotational axis that is tilted so much it lies nearly in the plane of its orbit.
answer
Uranus
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Which planet? ...is the planet with the highest average surface temperature.
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Venus
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Which planet? The planet that orbits closest to the Sun is
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Mercury
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Which planet? The only rocky planet to have more than one moon is
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Mars
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Which planet? ...is the jovian planet that orbits closest to the Sun.
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Jupiter
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Which planet? Most of the surface of ______ is covered with liquid water.
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Earth
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Which planet? ...is about 30 times as far from the Sun as our own planet.
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Neptune
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Which planet? The planet with the lowest average density is
answer
Saturn
question
Suppose you view the solar system from high above Earth's North Pole. Which of the following statements about planetary orbits will be true? The inner planets orbit the Sun counterclockwise while the outer planets orbit the Sun clockwise. All the planets except Uranus orbit the Sun counterclockwise; Uranus orbits in the opposite direction. The inner planets orbit the Sun clockwise while the outer planets orbit the Sun counterclockwise. All the planets orbit counterclockwise around the Sun.
answer
All the planets orbit counterclockwise around the Sun.
question
Which jovian planet does NOT have rings? Jupiter All the jovian planets have rings. Neptune Uranus
answer
All the jovian planets have rings
question
Which of the following statements about Pluto is true? It is orbited by only one moon. It is the largest known object that is considered to be a dwarf planet. Its mass is a little less than Earth's mass. It has more in common with comets in the Kuiper belt than it does with terrestrial planets like Earth.
answer
It has more in common with comets in the Kuiper belt than it does with terrestrial planets like Earth.
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How many Earths could fit inside Jupiter (assuming you could fill up all the volume)? The equation for the volume of a sphere is V=(43)πr3. (The radius of Jupiter is RJupiter = 71492 km.)
answer
1410
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How many Jupiters could fit inside the Sun? The equation for the volume of a sphere is V=(43)πr3.
answer
919
question
What is the Kuiper belt? a region of the solar system beginning just beyond the orbit of Neptune that contains many icy comets a region of the solar system that extends almost a fourth of the way to the nearest stars and contains a trillion comets with orbits going in all directions around the Sun the most prominent ring of Saturn that is visible in photographs a technical name for the asteroid belt
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a region of the solar system beginning just beyond the orbit of Neptune that contains many icy comets
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What is the Oort cloud? It is a giant storm in the atmosphere of Saturn. It is a great cloud of gas that resides far beyond the orbit of Pluto. It is another name for the cloud of gas from which our solar system was born. It's not really a cloud at all, but rather refers to the trillion or so comets thought to orbit the Sun at great distances
answer
It's not really a cloud at all, but rather refers to the trillion or so comets thought to orbit the Sun at great distances
question
Robotic spacecraft have different levels of complexity, which contributes to overall cost. Which of the following types of missions are likely to be the cheapest? flybys sample return missions orbiters lander
answer
flybys
question
Suppose observers at Earth's North Pole and South Pole use a transit of the Sun by Venus to discover that the angular diameter of Earth as viewed from Venus would be 62.8 arcseconds. Earth's radius is 6378 km. Estimate the distance between Venus and Earth in km and AU. Express your answer using two significant figures.
answer
distance = 4.2*10ˆ7km distance = 0.28 AU
question
Characteristics of Terrestrial Planets
answer
located within the inner solar system solid, rocky surface small size
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Characteristics of Jovian Planets
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extensive ring systems primarily composed of hydrogen, helium, and hydrogen compounds low average density numerous orbiting moons
question
Robotic spacecraft have different levels of complexity, which contributes to overall cost. Which of the following types of missions are likely to be the cheapest? orbiters sample return missions lander flybys
answer
flybys