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199 Cards in this Set
- Front
- Back
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When an electron in an atom goes from a higher energy state to a lower energy state, the atom
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emits a photon of a specific frequency.
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If you have a 100-watt light bulb, how much energy does it use each minute?
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6,000 joules
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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?
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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?
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An electron moves from an upper energy level to a lower one.
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Each of the following describes an "Atom 1" and an "Atom 2." In which case are the two atoms isotopes of each other?
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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 |
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What is the name given to 2H?
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deuterium
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An electron-volt is
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an amount of energy much smaller than a joule.
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What is a compound?
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a molecule containing two or more elements
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How many atoms fit across the period at the end of this sentence?
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millions
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From shortest to longest wavelength, which of the following correctly orders the different categories of electromagnetic radiation?
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gamma rays, X rays, ultraviolet, visible light, infrared, radio
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Grass (that is healthy) looks green because
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it reflects green light and absorbs other colors.
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From lowest energy to highest energy, which of the following correctly orders the different categories of electromagnetic radiation?
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radio, infrared, visible light, ultraviolet, X rays, gamma rays
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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?
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The star is moving away from us.
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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.)
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The blue star has a hotter surface temperature than the red star.
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If a material is highly opaque, then it
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absorbs most light.
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The study of energy levels in atoms is called
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quantum mechanics.
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Which of the following objects is not a close approximation of a thermal emitter?
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hot, thin gas
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If two objects are the same size but one object is 3 times hotter than the other object, the hotter object emits
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81 times more energy.
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Without telescopes or other aid, we can look up and see the Moon in the night sky because it
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reflects visible light.
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How does the spectrum of a molecule differ from the spectrum of an atom?
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A molecule has additional spectral lines due to changes in its rotational and vibrational energies.
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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?
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26 protons, 30 neutrons, 26 electrons
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The wavelength of a wave is
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the distance between two adjacent peaks of the wave
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Compared to the volume of its nucleus, the volume of an atom is about
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a trillion times greater.
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Which of the following statements about electrons is not true?
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Electrons orbit the nucleus rather like planets orbiting the Sun.
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Which of the following statements about thermal radiation is always true?
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A hot object emits photons with a higher average energy than a cool object.
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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?
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It releases a photon equal in energy to its own energy drop.
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Which of the following statements about X rays and radio waves is not true?
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Neither X rays nor radio waves can penetrate the earth's atmosphere.
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Which of the following cannot be described by a field?
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radiation pressure
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How much electrical charge does an atom with 6 protons, 6 neutrons, and 5 electrons have?
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a positive charge of +1
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Spectra from neutral atoms compared with spectra from ionized atoms of the same element
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have different sets of spectral lines.
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Dissociation is the process in which
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the bonds between atoms in a molecule are broken.
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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?
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The star is moving toward us.
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If a material is transparent, then it
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transmits light well.
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Which of the following statements about electrical charge is true?
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A positive charge and a negative charge will attract each other
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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
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an emission line spectrum.
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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?
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The atomic number is 79, and the atomic weight is 197.
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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?
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The galaxy is moving away from you.
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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?
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The total amount of light in the spectrum tells us the star's radius
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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?
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The line in the faster rotating star is broader.
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A gas heated to millions of degrees would emit
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mostly X rays.
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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?
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The gold ion has a charge of +2 and 77 electrons.
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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?
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The planet is rotating.
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In what wavelength range was interferometry first routinely used?
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radio
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What is an artificial star?
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a point of light in the earth's atmosphere created by a laser for the purpose of monitoring atmospheric fluctuations
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Which of the following could not be measured by an observation that uses only imaging?
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the rate at which a variable star brightens and dims
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Why do astronomers need different telescope designs to observe across the electromagnetic spectrum?
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Photons of different energy behave differently and require different collection strategies.
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What is the purpose of adaptive optics?
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to eliminate the distorting effects of atmospheric turbulence for telescopes on the ground
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Currently, the largest optical telescope mirrors have a diameter of
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10 m.
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Which of the following wavelength regions cannot be studied with telescopes on the ground?
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both B and C
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What do we mean by the diffraction limit of a telescope?
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t is the best angular resolution the telescope could achieve with perfect optical quality and in the absence of atmospheric distortion.
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Which of the following is always true about images captured with X-ray telescopes?
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They are always displayed in false color.
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Which of the following is a principal advantage of CCDs over photographic film?
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CCDs capture a much higher percentage of the incoming photons than does film.
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Which of the following is not an advantage of the Hubble Space Telescope over ground-based telescopes?
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It is closer to the stars.
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What does the technique of interferometry allow?
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It allows two or more telescopes to obtain the angular resolution of a single telescope much larger than any of the individual telescopes.
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Which of the following statements about light focusing is not true?
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The focal plane of a reflecting telescope is always located within a few inches of the primary mirror.
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At which wavelength range is there no current or planned space observatory?
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radio
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Which of the following studies is best suited to a timing experiment?
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studying whether a particular star's brightness is steady or variable
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Which of the following statements best describes the two principal advantages of telescopes over eyes?
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Telescopes can collect far more light with far better angular resolution.
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What is meant by spectral resolution?
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It is a measure of how close two spectral lines can be distinguished.
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Suppose the angular separation of two stars is smaller than the angular resolution of your eyes. How will the stars appear to your eyes?
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The two stars will look like a single point of light.
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Which of the following scenarios correctly demonstrates the tansformation of mass into energy as given by einstein's equation?
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When hydrogen is fused into helium, whether in the sun or in a nuclear bombn, the mass difference is turned into energy
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Which of the following is a form of electrial potentional energy?
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energy coming to your house from power companies
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what is the acceleration of gravity of earth
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energy coming to your house from power companies
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what is the acceleration of gravity of earth
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9.8 m/s(squared) downard
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which of the following statements is not one of newton's laws of motion?
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what goes up must come down
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If your mass is 60 kg on earth, what would your mass be on the Moon?
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60 kg
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At which lunar phase(s) are tides least pronounced (e.g., the lowest high tides)?
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both first and third quarters
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according to the universal law of gravitation, the force due to gravity
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nversely proportional to the square of the distance between objects
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According to what we now know from Newton's laws, which of the following best explains why Kepler's second law is true?
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A planet's angular momentum must be conserved as it moves around its orbit
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the orbital period of a geosynchronous satellite is
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23 hours and 56 minutes
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of the temperature ranges below, which range represents the smallest range of actual temperature?
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50-100 degrees Fahrenheit
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The allowed shapes for orbits under the force of gravity are
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ellipses, parabolas, and hyperbolas
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When a rock is held above the ground we say it has some potential energy. when we let it go, it fallsand we say the potential energy is converted to kinetic energy. finally, the rock hits the ground. what has happened to the energy?
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the energy goes to producing sound and to heating the ground, rock, and surrounding air
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Which of the following is not a conserved quantity?
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radiation
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The amount of gravitational potential energy released as an object falls depends on
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its mass and the distance it falls.
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Which of the following best describes the origin of ocean tides on Earth
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Tides are caused by the difference in the force of gravity exerted by the Moon across the sphere of the earth.
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In which of the following cases would you feel weightless
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while falling from a roof
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Each of the following lists two facts. Which pair can be used with Newton's version of Kepler's third law to determine the mass of the Sun?
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The earth is 150 million km from the Sun and orbits the Sun in 1 year.
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If an object's velocity is doubled, its momentum is
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doubled
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The fact that the Voyager spacecraft continue to speed out of the solar system, even though its rockets have no fuel, is an example of
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Newton's first law of motion.
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In the formula E = mc2, what does E represent?
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the mass-energy, or potential energy stored in an object's mass
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The force of gravity is an inverse square law. This means that, if you double the distance between two large masses, the gravitational force between them
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weakens by a factor of 4.
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The ultimate source of energy that powers the Sun is
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mass energy of hydrogen fusing into helium.
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A skater can spin faster by pulling in her arms closer to her body or spin slower by spreading her arms out from her body. This is due to
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conservation of angular momentum.
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Radiative energy is
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energy carried by light.
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The center of mass of a binary star system is
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the point at which the two objects would balance if they were somehow connected.
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Changing the orbit of a spacecraft by firing thrusters is an example of
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Newton's third law of motion.
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Suppose you heat up an oven and boil a pot of water. Which of the following explains why you would be burned by sticking your hand briefly in the pot but not by sticking your hand briefly in the oven?
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The water has a higher heat content than the oven.
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Absolute zero is
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0° Kelvin.
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The tides on Earth are an example of
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the universal law of gravitation.
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do uble the masses of both attracting objects, then the gravitational force between them will
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increase by a factor of 4.
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Where does the energy come from that your body uses to keep you alive?
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It comes from the foods you eat.
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According to the universal law of gravitation, if you triple the distance between two objects, then the gravitational force between them will
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decrease by a factor of 9.
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What quantities does angular momentum depend upon?
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mass, velocity, and radius
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Gasoline is useful in cars because it has
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chemical potential energy
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Suppose an object is moving in a straight line at 50 mi/hr. According to Newton's first law of motion, the object will
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continue to move in the same way until it is acted upon by a force
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Which object has the most kinetic energy?
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a 2-ton truck moving 90 km/hr
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Which of the following statements correctly describes the law of conservation of energy?
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The total quantity of energy in the universe never changes.
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You are standing on a scale in an elevator. Suddenly you notice your weight decreases. What do you conclude?
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You are standing on a scale in an elevator. Suddenly you notice your weight decreases. What do you conclude?
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The movement of a pool ball, after being struck by a cue, is an example of
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Newton's second law of motion.
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How does the Space Shuttle take off
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Hot gas shoots out from the rocket and, by conservation of momentum, the shuttle moves in the opposite direction
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Which of the following is not a unit of energy?
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kilowatt
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Suppose a lone asteroid happens to be passing relatively near Jupiter (but not near any of its moons), following a hyperbolic orbit as it approaches Jupiter. Which of the following statements would be true?
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The asteroid's orbit around Jupiter would not change, and it would go out on the same hyperbolic orbit that it came in on.
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If you drop a rock from a great height, about how fast will it be falling after 5 seconds, neglecting air resistance?
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50 m/s
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Considering Einstein's famous equation, E = mc2, which of the following statements is true?
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A small amount of mass can be turned into a large amount of energy.
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As long as an object is not gaining or losing mass, a net force on the object will cause a change in
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velocity
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The mass of Jupiter can be calculated by
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measuring the orbital period and distance of one of Jupiter's moons.
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Momentum is defined as
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mass times velocity.
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What would happen if the Space Shuttle were launched with a speed greater than the earth's escape velocity?
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It would travel away from the earth into the solar system
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What does temperature measure?
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the average kinetic energy of particles in a substance
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What is the meaning of the word Cosmos?
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The sum total of all matter and energy, that is, everything within and between all galaxies
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Which of the following has your "address" in the correct order?
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you, Earth, solar system, Milky Way, Local Group, Local Supercluster
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About where is our solar system located within the Milky Way galaxy?
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about two-thirds of the way from the center of the galaxy to the outskirts of the galactic disk
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Roughly how many stars are in the Milky Way Galaxy?
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100 billion
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Modern telescopes are capable of seeing bright galaxies up to about
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10 billion light years away
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Suppose we imagine the Sun to be about the size of grapefruit. How big an area would the orbits of the nine planet of the Solar System cover?
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the size of a typical campus
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What do we mean when we say that the universe is expanding?
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Average distances are increasing between galaxies.
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The age of the universe is
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between 10 billion and 16 billion years.
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How are galaxies important to our existence?
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Galaxies recycle heavy elements produced in stars into future generations of stars
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The earth is made mostly of metals and rocks. Where did this material come from?
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it was produced by nuclear fusion in stars.
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What is nuclear fusion?
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the process of combining lightweight nuclei to make heavier nuclei
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Why does Carl Sagan say that we are star stuff?
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Nearly every atom from which we are made once ( before the solar system formed) was inside of a star
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Which of the following statements does not NOT use the term LIGHT-YEAR in an appropriate way?
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it will take me light-years to complete this homework assignment.
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One LIGHT-HOUR is the distance that light travels in an hour. How far is this, in kilometers? ( Recall that the speed of light is 300,000 km/s.)
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1.08 billion km
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What do we mean by the observable universe?
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the part of the universe that could be observed in principle, including things that may require future technologies
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Suppose we imagine the Sun to be about the size of grapefruit. Which of the following describes the size and distance of the earth on the same scale?
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The earth is the size of a point about 15 meters away from the Sun.
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What is the Sun mainly made of?
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hydrogen and helium
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Which of the following is the smallest?
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size of a typical planet
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Which of the following is the largest?
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size of a typical galaxy
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If we use 1 millimeter to represent 1 light-year, how large in diameter is the Milky Way Galaxy?
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100 meters
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How long would it take to count all the stars in the Milky Way Galaxy at a rate of one star per second
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several thousand years
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If you represented each star by a grain of sand, how much sand would it take to represent all the stars in the universe?
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more than all the sand on all the beaches on Earth.
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On the scale of the cosmic calendar, in which the history of the universe is compressed to 1 year, how long has human civilization (i.e., since ancient Egypt) existed?
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a few seconds
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On a cosmic calendar, in which the history of the universe is compressed into 1 year, when did the dinosaurs become extinct?
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in late December
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On a cosmic calendar, in which the history of the universe is compressed into 1 year, when did Kepler and Galileo first discover that we live on planet in a solar system?
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1 second ago
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On a cosmic calendar, in which the history of the universe is compressed into one year. how long is the average human life span
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0.2 second
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Approximately how fast are you moving with the rotation of the earth?
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1,300 km/hr
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What is an astronomical unit?
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the average distance from the earth to the Sun.
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Patterns of starts in constellations hardly change in appearance over times of even a few thousand years. Why?
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The stars in our sky acutally move rapidly relative to us- thousands of kilometers per hour- but are so far away taht it takes a long time for this motion to make a noitceable change in the patterns in the sky.
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How long does it take our solar system to complete one orbit around the Milky Way Galaxy?
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230 million years
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Which of the following statments about the Milky Way Galaxy is NOT true?
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Our solar system is located very close to the center of the Milky Way Galaxy.
FEEDBACK: The solar system is located about 28,000 light-years from the galactic center. |
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Which of the following correctly lists speeds from slowest to fastest?
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Earth's speed of rotation on it s axis, Earth's speed of revolustion about the Sun, typical speeds of stars in the local solar neighborhood relative to us, the speed of our solar system orbiting the center of the Milky Way Galaxy, the speeds of very distant galaxies relative to us.
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Most of the mass in the Milky Way Galaxy is located
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n the halo (above/below the disk)
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From the fact that virtually every galaxy is moving away from us and more distant galaxies are moving away from us at a faster rate than closer ones, we conclude that
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the universe is expanding.
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By studying distant galaxies in the 1920s, Hubble made the following important discovery that led us to conclude that the universe is expanding:
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all galaxies outside the Local Group are moving away from us, and the farther away they are, the faster they're going.
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Imagine that we put a raisin cake into the oven, with each raisin separated from the others by 1 cm. An hour later, we take it out and the distances between raisins are 3 cm. if you lived in one of the raisins and watched the other raisins as the cake expanded, which of the following would you conclude?
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More distant raisin would be moving away from you faster.
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Which scientists played a major role in overturning the ancient idea of an Earth-centered universe, and about when?
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Copernicus, Kepler, and Galieo; about 400 years ago
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Our solar system is located in the center of the Milky Way Galaxy.
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false
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The Milky Way is moving further away from most other galaxies in the Universe.
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True
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No galaxies existed before the Big Bang.
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True
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The earth is always precisely 1 AU from the Sun.
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False
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Which of the following statments about the Milky Way Galaxy is NOT true?
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Our solar system is located very close to the center of the Milky Way Galaxy.
FEEDBACK: The solar system is located about 28,000 light-years from the galactic center. |
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Most of the mass in the Milky Way Galaxy is located
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n the halo (above/below the disk)
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From the fact that virtually every galaxy is moving away from us and more distant galaxies are moving away from us at a faster rate than closer ones, we conclude that
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the universe is expanding.
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By studying distant galaxies in the 1920s, Hubble made the following important discovery that led us to conclude that the universe is expanding:
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all galaxies outside the Local Group are moving away from us, and the farther away they are, the faster they're going.
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Imagine that we put a raisin cake into the oven, with each raisin separated from the others by 1 cm. An hour later, we take it out and the distances between raisins are 3 cm. if you lived in one of the raisins and watched the other raisins as the cake expanded, which of the following would you conclude?
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More distant raisin would be moving away from you faster.
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Which scientists played a major role in overturning the ancient idea of an Earth-centered universe, and about when?
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Copernicus, Kepler, and Galieo; about 400 years ago
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Our solar system is located in the center of the Milky Way Galaxy.
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false
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The Milky Way is moving further away from most other galaxies in the Universe.
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True
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Which of the following is not a phase of the moon?
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half moon
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What is the saros cycle?
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the 18-year cycle over which the pattern of eclipses repeats
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How many stars can you see with your naked eye on a clear, moonless night from a dark location?
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a few thousand
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All of the following statements are true. Which one explains the reason why there is not a solar eclipse at every moon?
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the orbital plane of the Moon is titled by about 5 degrees to the ecliptic plane.
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What is the ecliptic?
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the Sun's apparent path along with the celestial sphere
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In which direction does a quarter moon rise?
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east
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If it is midnight in New York, it is
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daytime in Sydney, Australia
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What happens during the apparent retrograde motion of a planet?
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The planet appears to move eastward with respect to the stars over a period of many nights
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Why dowe see essentially the same face of the moon at all times?
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because the Moon's rotational and orbital periods are equal
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Which of the following statements about stellar parallax is true?
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The closer a star is to us, the more parallax it exhibits
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At approximately what time would a full moon be on your meridian?
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midnight
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If the Moon is rising at midnight, the phase of the Moon must be
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third quarter
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Orion is visible on winter evenings but not summer evenings because of
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the location of the earth in its orbit
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At approximately what time would a first quarter moon rise?
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noon
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What conditions are required for a lunar eclipse?
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The phase of the Moon must be full, and the nodes of the Moon's orbit must be nearly aligned with the earth and the Sun
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What causes the apparent retrograde motion of the planets?
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As the earth passes another planet, the other planet appears to move backward with respect to the background stars, but the planet's motion does not really change
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Which of the following statements does not use the term angular size or angular distance correctly?
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The angular distance between those two bright stars in the sky is about 2 meters
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Which of the following correctly describes the meridian in your sky?
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a half-circle extending from your horizon due north, through your zenith, to your horizon due south
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If the Moon rises around 3 A.M., its phase must be
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waning crescent
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Which of the following statements about circumpolar stars is true at all latitudes?
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they always remain above your horizon
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Suppose you live on the Moon. how long is a day (i.e., from sunrise to sunrise)?
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a lunar month
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Which of the following statements about constellations is false?
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Most constellations will be unrecognizable hundreds of years from now
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What makes the North Star, Polaris, special?
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it appears very near to the north celestial pole
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Which of the following statements about the Moon is true?
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The Moon's distance from the earth varis during its orbit
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We describe a position on the earth's surface by stating its
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latitude and longtitude
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Why do we have seasons on earth?
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As the earth goes around the Sun and the earth's axis remains pointed toward Polaris, the Northern and Southern hempishere lternatiely recieve more and less direct sunlight
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We can't detect stellar parallax with naked eye observations. which of the folloiwing would make parallax easier to observe?
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increasing the size of the earth's orbit
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what is a circumpolar star?
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a star that always remains above your horizion
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what effect or effects would be most signficiant if the Moon's orbital plane were exactly the same as the ecliptic plane?
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Solar eclipses would be much more frequent
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When someone on earth observes the Moon in the first=quarter phase, someone on the Moon facing the earth observes the earth in the..
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third-quarter earth phase
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Which of the following best describes the modern definition of a constellation?
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a region of the celestial sphere
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Why were ancient people unable to detect stellar parallax?
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they did not have the ability to measure very small angles.
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Which of the following statements about the celestial equtor is true at all latitudes?
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It repreesents an extension of the earth's equator onto the celestial sphere
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Which of the following never goes in retrograde motion
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the sun
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if the moon is setting at 6 AM., the phase of the moon must be full.
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full
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When are eclipse seasons?
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when the nodes of the moon's orbit are nearly aligned with the sun
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the precession of the moon's nodes means that
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the eclipse seasons occur less than 6 months apart
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Ashen light (or earthshine) is..
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sunlight reflected by the earth that illuminates the "dark" potion of the moon
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Why is it summer in the Northern Hampshire when it's winter in the south Hemisphere?
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The Northern Hemisphere is titled toward the Sun and receives more direct sunlight
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How many arcseconds are in 1 degree?
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3,600
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