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379 Cards in this Set
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1. The mean distance of Saturn from the Sun, 1,427,000,000 km, can be written in shorthand notation as
Answer: A. 1.427 × 10 6 km. B. 0.1427 × 10 9 km. C. 1.427 × 10 7 km. D. 1.427 × 10 9 km. |
D. 1.427 × 10 9 km
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Seasonal variations on a planet's surface are caused by
A. clouds that periodically form and disappear as the planet orbits the Sun. B. the tilt of the planet's spin axis with respect to the perpendicular to its orbital plane. C. volcanoes that erupt periodically because of tidal interactions and obscure the atmospheres of planets. D. the variation of the planet's distance from the Sun during its passage along its elliptical orbit. |
B. the tilt of the planet's spin axis with respect to the perpendicular to its orbital plane.
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In the system of celestial coordinates that matches latitude and longitude on the Earth, which is the coordinate that is equivalent to longitude?
Answer: A. declination B. elongation angle C. precession D. right ascension |
D. right ascension
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The ecliptic can be defined as the
Answer: A. extension of the Earth's equator onto the sky. B. plane that is perpendicular to the Earth's spin axis. C. path traced out by the Moon in our sky in one month against the background stars. D. path traced out by the Sun in our sky over one year against the background stars. |
D. path traced out by the Sun in our sky over one year against the background stars.
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In the southern hemisphere, day and night are of equal duration on about
Answer: A. March 21. B. December 21. C. January 1, by definition. D. June 21. |
A. March 21.
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Approximately when does a full Moon rise,?
A. noon B. midnight C. sunrise D. sunset |
D. sunset
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A solar eclipse occurs on the
Earth when the A. Moon casts a shadow on the Earth. B. Earth casts a shadow on the Moon. C. Sun passes in front of the Moon. D. Moon passes behind the Sun. |
A. Moon casts a shadow on the Earth.
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What is the phase of the Moon during a total lunar eclipse?
A. new B. full C. gibbous D. first quarter |
B. full
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The mean distance of Saturn from the Sun, 1,427,000,000 km, can be written in shorthand notation as
A. 1.427 × 106 km. B. 0.1427 × 109 km. C. 1.427 × 107 km. D. 1.427 × 109 km. |
D. 1.427 × 109 km.
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The diameter of the hydrogen atom, 0.000,000,000,11 m, can be written in shorthand notation as
A. 1.1 × 10–8 m. B. 1.1 × 10–10 m. C. 1.1 × 10–9 m. D. 1.1 × 10–11 m. |
B. 1.1 × 10–10 m.
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The bright stars Vega, Deneb, and Altair form
A. the summer triangle. B. the winter triangle. C. the Big Dipper. D. Orion, the Hunter. |
A. the summer triangle.
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Which of the following lines or points is always directly over your head, no matter where on the
Earth you go? A. celestial equator B. ecliptic C. zenith D. 90° north declination |
C. zenith
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The celestial equator is defined as the
A. line in the sky that is perpendicular to Earth's spin axis. B. line traced in the sky by the Moon each month against the background stars. C. line traced in the sky by the Sun over one year against the background stars. D. band of constellations through which the Sun and Moon move in our sky. |
A. line in the sky that is perpendicular to Earth's spin axis.
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The most readily observed east-to-west motion of objects in the night sky is caused by the
A. relative motions of stars with respect to each other in the sky. B. rotation of the Earth on its axis. C. rotation of the whole universe around a fixed Earth. D. revolution of the Earth in its orbit around the Sun. |
B. rotation of the Earth on its axis.
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Where would you have to be to see the south celestial pole on your horizon?
A. about 1° away from the South Pole, to allow for the Earth's precession B. at the South Pole of Earth C. at the North Pole of Earth D. on the equator |
D. on the equator
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The Sun appears to be about ° in diameter. On the equator, approximately how long does it take
for the Sun to set, from first contact with the horizon to complete disappearance below the horizon? A. 2 seconds B. about 1 hour C. 4 minutes D. 2 minutes |
D. 2 minutes
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The ecliptic can be defined as the
A. extension of the Earth's equator onto the sky. B. plane that is perpendicular to the Earth's spin axis. C. path traced out by the Moon in our sky in one month against the background stars. D. path traced out by the Sun in our sky over one year against the background stars. |
D. path traced out by the Sun in our sky over one year against the background stars.
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In which direction does the Sun appear to move along the ecliptic over the course of a year,
relative to the background stars? A. west B. northwest C. southwest D. east |
D. east
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If we could see background stars in the daytime, the Sun would
A. appear to move eastward against them at a rate of 15° per day. B. appear to move westward against them at a rate of 1° per day. C. remain stationary against them. D. appear to move eastward against them at a rate of 1° per day. |
D. appear to move eastward against them at a rate of 1° per day.
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The ecliptic crosses the celestial equator
A. at two points, known as equinoxes. B. on the meridian. C. at two points, known as solstices. D. at one point only, known as the vernal equinox. |
A. at two points, known as equinoxes.
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The Earth would NOT have seasons if
A. its equatorial plane were perpendicular to its orbital plane. B. its axis of rotation were perpendicular to its equatorial plane. C. the observer's vertical axis (zenith) were perpendicular to the Earth's orbital plane. D. its axis of rotation were perpendicular to its orbital plane. |
D. its axis of rotation were perpendicular to its orbital plane.
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The reason Earth experiences seasons is that
A. Earth's rotation axis is not perpendicular to the ecliptic. B. Earth's rotation axis is not perpendicular to the ecliptic, and the direction in which this axis points changes with time. C. Earth is closer to the Sun during part of the year. D. the Moon pulls on Earth from a distance that varies over the year. |
A. Earth's rotation axis is not perpendicular to the ecliptic.
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When the northern hemisphere is experiencing winter, the
A. Earth is closer to the Sun than it is during northern summer. B. Earth is farther from the Sun than it is during the northern summer. C. Earth is the same distance from the Sun as it is the rest of the year because Earth's orbit is circular with the Sun in the center. D. southern hemisphere is experiencing winter also. |
A. Earth is closer to the Sun than it is during northern summer.
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Where would you have to be in either the northern or southern hemisphere for the Sun to remain below the horizon for a 24-hour period for at least part of a year?
A. nowhere because the Sun is always visible at some time of the day everywhere on Earth B. above about 66.5° latitude C. above about 23.5° latitude D. only at 90°, or exactly at the poles |
B. above about 66.5° latitude
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17. Which of the following is the correct sequence of appearances of Moon phases in the sky?
A. waxing crescent, first quarter, waxing gibbous, full Moon B. new Moon, full Moon, waxing crescent, waning crescent C. full Moon, waxing gibbous, third quarter, waning crescent D. new Moon, waning crescent, first quarter, full Moon |
A. waxing crescent, first quarter, waxing gibbous, full Moon
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When the Moon is in its gibbous phase, the positions of the Moon, the Earth, and the Sun are such
that the A. Moon is closer to the Sun than the Earth is. B. relative distances of the Earth and the Moon from the Sun are irrelevant because this phase can occur at any time. C. Earth and the Moon are at almost the same distance from the Sun. D. Moon is farther from the Sun than the Earth is. |
D. Moon is farther from the Sun than the Earth is.
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What is the phase of the moon during a total solar eclipse?
Answer: A. crescent B. first quarter C. full D. new |
D. new
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In the ancient Greek era, it was almost universally believed that the:
A. pole star represented the center of the universe about which the Earth and all other objects revolved. B. Milky Way represented the observable universe, and its center was the center of the universe. C. Sun was at the center of the universe. D. Earth was at the center of the universe. |
D. Earth was at the center of the universe.
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A major contribution of Ptolemy to the development of astronomy was
A. origination of the idea of a geocentric (Earth-centered) cosmology, which was later developed by Aristarchus. B. derivation of a model for the solar system in which the planets move around the Sun in circular orbits. C. derivation of the model for the solar system in which the planets move around the Earth in elliptical orbits, moving fastest when closest to the Earth. D. derivation of a model for the solar system in which the planets moved in epicycles and the epicycles orbited the Earth. |
D. derivation of a model for the solar system in which the planets moved in epicycles and the epicycles orbited the Earth.
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Kepler's first law states that the orbit of a planet about the Sun is a(n)
A. circle with the Sun at the center. B. oval with the Sun at the center. C. ellipse with the Sun at one focus. D. ellipse with the Sun at the center. |
C. ellipse with the Sun at one focus.
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A space probe is put into a circular orbit around the Sun at a distance of exactly 2 AU from the
Sun. According to Kepler's third law, how long does it take this probe to orbit the Sun once? A. 1.6 years (cube root of 4) B. 1 year C. 8 years D. 2.8 years (square root of 8) |
D. 2.8 years (square root of 8)
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1 AU, or 1 astronomical unit, is defined as the
A. distance at which the Earth-Sun distance will subtend an angle of 1 arc second. B. mean distance between the Sun and the Earth. C. radius of the Sun. D. distance traveled by light in 1 year. |
B. mean distance between the Sun and the Earth.
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What path would a planet (like the Earth!) take if the force of gravity from the Sun were to be
suddenly removed? A. The planet would move in a straight line tangential to its present orbit. B. The planet would stop moving altogether because there would be no gravity acting on it. C. The planet would move in a straight line outward, directly away from the Sun's position. D. The planet would begin to move in a long ellipse with the Sun at one focus. |
A. The planet would move in a straight line tangential to its present orbit.
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The smooth surfaces of the lunar maria were most likely caused by
A. lava flows in the early history of the Moon. B. dust storms that smoothed and covered the surface. C. volcanic ash that rained on the surfaces of the basins in ancient times. D. water flowing into the basins and allowing sediments to settle over their surfaces. |
A. lava flows in the early history of the Moon.
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Spring tides occur
A. once a day. B. once a month, at full Moon. C. twice a month, at full and new Moon. D. once a year, in springtime. |
C. twice a month, at full and new Moon.
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Most of the craters on the Moon are thought to have been caused by
A. collapse of volcanic domes, leaving central peaks in the craters. B. volcanic activity, leaving behind volcano craters similar to those on Earth. C. continuous bombardment throughout the Moon's life, including the present and recent past, by large and small asteroids. D. intense bombardment by large and small bodies over some specific early period in the Moon's history. |
D. intense bombardment by large and small bodies over some specific early period in the Moon's history.
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Of what material is the core of Earth composed?
A. mostly iron B. roughly half rock and half iron C. titanium and nickel D. rock of similar composition to that in the crust, but much denser |
A. mostly iron
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The overall shape of the orbits of most of the planets in the solar system is
A. perfectly circular. B. parabolic. C. slightly elliptical, but nearly circular. D. elliptical, very elongated. |
C. slightly elliptical, but nearly circular.
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In our solar system, which of the following planets is a member of the terrestrial group?
A. Neptune B. Saturn C. Jupiter D. Mars |
D. Mars
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The African and South American continents are separating at a rate of about 3 cm per year, according to the ideas of plate tectonics. If they are now 5000 km apart and have moved at a constant speed over this time, how long is it since they were in contact?
A. 1.7 million years B. 170 million years C. 170 thousand years D. 1.7 billion years |
B. 170 million years
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Auroral displays are most often seen
A. at the north and south geographical poles, along Earth's spin axis. B. directly above the north and south geomagnetic poles. C. in two bands on either side of the equator, in the tropics. D. in circular regions around the north and south geomagnetic poles. |
D. in circular regions around the north and south geomagnetic poles.
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The dominant component of the soil on Mars is probably
A. sedimentary rocks laid down by massive floods early in Mars's history. B. volcanic ash from eruptions in recent geological times. C. basaltic lava pulverized by meteoritic bombardment. D. iron oxides. |
D. iron oxides.
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The major planet whose spin axis lies almost in its orbital plane is
A. Neptune. B. Uranus. C. Mars. D. Mercury. |
B. Uranus.
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A comet's tail always
A. points toward the nearest planet, attracted by the planet's gravity field as the comet passes by the planet. B. trails behind the comet in its orbit and so points away from the Sun only while the comet is approaching the Sun. C. points away from the Sun, regardless of the motion of the comet. D. points toward the Sun because the tail is caused by jets of gases evaporated from the comet's nucleus on the side heated by the Sun. |
C. points away from the Sun, regardless of the motion of the comet.
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A meteor shower, or the appearance of many more “shooting stars” at a particular time in the year from a specific sky direction, is related to which astronomical phenomenon?
A. passage of Earth through the remnants of an old comet B. passage of Earth through intense streams of solar wind C. Earth's passage through part of the asteroid belt D. Earth's passage through different parts of the spiral arms of the Galaxy |
A. passage of Earth through the remnants of an old comet
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Violet light differs from red light in that it
A. travels more quickly (through a vacuum) than red light. B. has a shorter wavelength than red light. C. travels more slowly (through a vacuum) than red light. D. has a longer wavelength than red light |
B. has a shorter wavelength than red light.
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By what factor is the light-gathering power of the 10-m diameter Keck telescope on Mauna Kea in
Hawaii greater than an average unaided human eye, with a typical aperture diameter of 5 mm? A. 2.5 × 105 times B. 2 × 104 times C. 2000 times D. 4 × 106 times |
D. 4 × 106 times
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Wien's law, relating the peak wavelength λmax of light emitted by a dense object to its temperature T, can be represented by
A. λmax = constant × T4. B. λmaxT = constant. C. λmax = constant/T2. D. λmax/T = constant. |
B. λmaxT = constant.
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Wien's law, relating the peak wavelength λmax of light emitted by a dense object to its temperature T, can be represented by
A. λmax = constant × T4. B. λmaxT = constant. C. λmax = constant/T2. D. λmax/T = constant. |
B. λmaxT = constant.
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The dominant energy source that powers the Sun at the present time is
A. the release of gravitational energy as the Sun slowly contracts. B. thermonuclear fusion of hydrogen into helium in the core. C. thermonuclear fission of helium into hydrogen in the core. D. thermonuclear fusion of helium into heavier elements in the core. |
B. thermonuclear fusion of hydrogen into helium in the core.
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What name is given to the outer atmosphere of the Sun?
A. convective zone B. radiative zone C. corona D. chromosphere |
C. corona
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What is nuclear fusion?
A. nucleus transforming into a nucleus of a different element by emitting an electron and a neutrino B. removal of electrons from atoms to form ions C. two nuclei sticking together to form a new, heavier nucleus D. heavy nucleus splitting apart to form two lighter nuclei |
C. two nuclei sticking together to form a new, heavier nucleus
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Two stars are found to have the same luminosity. However, one star has twice the surface
temperature of the other. From this information, what can you determine about their radii? A. The hotter star has half the radius of the cooler star. B. The cooler star has half the radius of the hotter star. C. The hotter star has a quarter the radius of the cooler star. D. Nothing can be determined about the radii from this information. |
C. The hotter star has a quarter the radius of the cooler star.
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Apparent magnitude is a measure of a star's
A. intrinsic brightness (actual light output). B. size (diameter). C. temperature. D. brightness, as seen from Earth. |
D. brightness, as seen from Earth.
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Apparent magnitude is a measure of a star's
A. intrinsic brightness (actual light output). B. size (diameter). C. temperature. D. brightness, as seen from Earth. |
D. brightness, as seen from Earth.
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Which important stellar parameter can be derived from the study of binary stars mutually bound to
each other by gravitational forces? A. stellar masses B. distance of the stars from Earth C. age of the stars D. surface temperatures of the stars |
A. stellar masses
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The luminosity of a star is
A. its brightness as seen by people on Earth. B. its brightness if it were at a distance of 10 pc (32.6 ly) from Earth. C. its total energy output into all space. D. another name for its color or surface temperature. |
C. its total energy output into all space.
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The luminosity of a star is
A. its brightness as seen by people on Earth. B. its brightness if it were at a distance of 10 pc (32.6 ly) from Earth. C. its total energy output into all space. D. another name for its color or surface temperature. |
C. its total energy output into all space.
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What is parallax?
A. distance to an object, measured in parsecs B. angle taken up by the size (e.g., diameter) of an object, as seen by an observer C. shift in angular position of an object as it moves in space D. apparent shift in position of an object as the observer moves |
D. apparent shift in position of an object as the observer moves
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What is parallax?
A. distance to an object, measured in parsecs B. angle taken up by the size (e.g., diameter) of an object, as seen by an observer C. shift in angular position of an object as it moves in space D. apparent shift in position of an object as the observer moves |
D. apparent shift in position of an object as the observer moves
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What will our Sun become at the END of its death cycle?
1. Red Giant 2. Neutron Star 3. White Dwarf 4. Black Hole |
3. White Dwarf
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What is the source of most of the heavy elements on Earth and in our own bodies?
A. thermonuclear fusion reactions in the cores of massive stars before the supernova phase B. explosive nucleosynthesis during supernova explosions of massive stars C. vosmic ray interactions with hydrogen and helium nuclei in interstellar clouds D. nuclear reactions during the formation of the universe (the Big Bang) |
B. explosive nucleosynthesis during supernova explosions of massive stars
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What is a pulsar?
A. very hot material orbiting a black hole B. Cepheid variable star with a period of a few days C. pulsating white dwarf star, fluctuating rapidly in brightness D. rapidly rotating neutron star, producing beams of radio energy and occasionally of X rays and visible light |
D. rapidly rotating neutron star, producing beams of radio energy and occasionally of X rays and visible light
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The diameter of a typical neutron star of 1 solar mass is predicted to be approximately
A. 1 km. B. that of an average city, a few kilometers. C. that of the Sun. D. that of Earth, 12,800 km. |
B. that of an average city, a few kilometers.
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According to general relativity, why does Earth orbit the Sun?
A. Matter contains quarks, and Earth and the Sun attract each other with the “color force” between their quarks. B. Space around the Sun is curved, and Earth follows a geodesic in this curved space. C. The Sun exerts a gravitational force on Earth across empty space. D. Earth and the Sun are continually exchanging photons of light in a way that holds Earth in orbit. |
B. Space around the Sun is curved, and Earth follows a geodesic in this curved space.
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What is the likely final fate of a star of 15 solar masses when it is on the main sequence? A. The star will collapse and become a black hole.
B. The star will condense to the point where it is composed completely of neutrons, the degeneracy of which will prevent further shrinkage. C. The degeneracy of the electrons in the star will prevent collapse below the diameter of a white dwarf. D. The star will immediately split in two and become a binary star system. |
B. The star will condense to the point where it is composed completely of neutrons, the degeneracy of which will prevent further shrinkage.
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What is the likely final fate of a star of 15 solar masses when it is on the main sequence? A. The star will collapse and become a black hole.
B. The star will condense to the point where it is composed completely of neutrons, the degeneracy of which will prevent further shrinkage. C. The degeneracy of the electrons in the star will prevent collapse below the diameter of a white dwarf. D. The star will immediately split in two and become a binary star system. |
B. The star will condense to the point where it is composed completely of neutrons, the degeneracy of which will prevent further shrinkage.
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What is it that is actually located at the event horizon of a black hole?
A. infinitely dense concentration of mass B. magnetic field of immense strength C. nothing specific D. sphere of photons |
C. nothing specific
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What is it that is actually located at the event horizon of a black hole?
A. infinitely dense concentration of mass B. magnetic field of immense strength C. nothing specific D. sphere of photons |
C. nothing specific
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What would happen to the gravitational force on Earth if the Sun were to be replaced by a 1-solar-mass
black hole? A. The gravitational force on Earth would become extremely high, sufficient to pull Earth into the black hole. B. The gravitational force on Earth would double in strength. C. The gravitational force on Earth would remain as it is now. D. The gravitational force on Earth would be much less because the gravitational field of a black hole exists only very close to it. |
C. The gravitational force on Earth would remain as it is now.
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What would happen to the gravitational force on Earth if the Sun were to be replaced by a 1-solar-mass
black hole? A. The gravitational force on Earth would become extremely high, sufficient to pull Earth into the black hole. B. The gravitational force on Earth would double in strength. C. The gravitational force on Earth would remain as it is now. D. The gravitational force on Earth would be much less because the gravitational field of a black hole exists only very close to it. |
C. The gravitational force on Earth would remain as it is now.
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The possible presence of a supermassive black hole at the center of the Milky Way Galaxy has been
deduced from A. gravitational radiation emitted by stars as they are swallowed by the black hole. B. powerful magnetic fields in the huge filaments arching away from (or toward) the center. C. the number of globular clusters that concentrate toward the galactic center. D. the very high orbital speed of ionized gas clouds close to the galactic center. |
D. the very high orbital speed of ionized gas clouds close to the galactic center.
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The Sun's position in the Milky Way Galaxy is
A. unknown because our view is too severely restricted by interstellar dust. B. in the disk of the Galaxy, inside a spiral arm or segment of a spiral arm. C. in the disk of the Galaxy, between and well away from any spiral arm. D. in the spherical halo, somewhat above and outside the spiral arms. |
B. in the disk of the Galaxy, inside a spiral arm or segment of a spiral arm.
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The Local Group is
A. the name of the spiral arm of the Milky Way Galaxy in which the Sun is located. B. a cluster of galaxies in which the Milky Way is located. C. the family of planets around the Sun. D. a star cluster to which the Sun belongs. |
B. a cluster of galaxies in which the Milky Way is located.
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The Local Group is
A. the name of the spiral arm of the Milky Way Galaxy in which the Sun is located. B. a cluster of galaxies in which the Milky Way is located. C. the family of planets around the Sun. D. a star cluster to which the Sun belongs. |
B. a cluster of galaxies in which the Milky Way is located.
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Where do we find supermassive black holes?
A. in the centers of giant elliptical galaxies B. in the centers of active galaxies C. in the centers of both active and normal galaxies, but only those at relatively high redshift values, indicating that they existed in the distant past D. in the centers of both active and normal galaxies, both nearby and far away |
D. in the centers of both active and normal galaxies, both nearby and far away
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Where do we find supermassive black holes?
A. in the centers of giant elliptical galaxies B. in the centers of active galaxies C. in the centers of both active and normal galaxies, but only those at relatively high redshift values, indicating that they existed in the distant past D. in the centers of both active and normal galaxies, both nearby and far away |
D. in the centers of both active and normal galaxies, both nearby and far away
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Why is the universe expanding?
A. The energy from all the stars is heating the universe, making it expand like a gas that is heated. B. Spacetime itself is expanding, carrying the galaxies (or superclusters of galaxies) with it. C. The universe is not expanding—it is we who are getting smaller, making the universe seem bigger and bigger. D. An infinitely dense clump of matter exploded, sending the galaxies (or superclusters of galaxies) hurtling out through space. |
B. Spacetime itself is expanding, carrying the galaxies (or superclusters of galaxies) with it.
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Why is the universe expanding?
A. The energy from all the stars is heating the universe, making it expand like a gas that is heated. B. Spacetime itself is expanding, carrying the galaxies (or superclusters of galaxies) with it. C. The universe is not expanding—it is we who are getting smaller, making the universe seem bigger and bigger. D. An infinitely dense clump of matter exploded, sending the galaxies (or superclusters of galaxies) hurtling out through space. |
B. Spacetime itself is expanding, carrying the galaxies (or superclusters of galaxies) with it.
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The mass of the electron, 0.000,000,000,091 kg, can be written in shorthand notation as
A. 0.91 × 10–11 kg. B. 9.1 × 10–12 kg. C. 9.1 × 10–11 kg. D. 9.1 × 10–10 kg. |
C. 9.1 × 10–11 kg.
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From any location on Earth, the zenith defines a direction
A. vertically above the North Pole. B. vertically above an observer. C. toward the Sun at noon. D. vertically above a point on the equator. |
B. vertically above an observer.
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From any location on Earth, the zenith defines a direction
A. vertically above the North Pole. B. vertically above an observer. C. toward the Sun at noon. D. vertically above a point on the equator. |
B. vertically above an observer.
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The nightly motion of objects across our sky from horizon to horizon is caused by the
A. motion of the solar system around the Galaxy. B. revolution of the Earth around the Sun. C. rotation of the whole celestial sphere of stars around the fixed Earth. D. rotation of the Earth on its axis. |
D. rotation of the Earth on its axis.
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The nightly motion of objects across our sky from horizon to horizon is caused by the
A. motion of the solar system around the Galaxy. B. revolution of the Earth around the Sun. C. rotation of the whole celestial sphere of stars around the fixed Earth. D. rotation of the Earth on its axis. |
D. rotation of the Earth on its axis.
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In the southern hemisphere, day and night are of equal duration on about
A. March 21. B. December 21. C. January 1, by definition. D. June 21. |
A. March 21.
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In the southern hemisphere, day and night are of equal duration on about
A. March 21. B. December 21. C. January 1, by definition. D. June 21. |
A. March 21.
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Precession is the
A. slow coning motion of the spin axis of the Earth, similar to that of a spinning top. B. gradual reversal of the Earth's magnetic field. C. motion of the Earth along its orbital path during a year. D. daily spinning motion of the Earth, producing the apparent motion of the Sun and the stars. |
A. slow coning motion of the spin axis of the Earth, similar to that of a spinning top.
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Precession is the
A. slow coning motion of the spin axis of the Earth, similar to that of a spinning top. B. gradual reversal of the Earth's magnetic field. C. motion of the Earth along its orbital path during a year. D. daily spinning motion of the Earth, producing the apparent motion of the Sun and the stars. |
A. slow coning motion of the spin axis of the Earth, similar to that of a spinning top.
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The center, or fixed point, of the Greek model of the universe was
A. the center of the galaxy. B. a point midway between the Earth and the Sun. C. the Sun's center. D. close to the Earth's center. |
D. close to the Earth's center.
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The center, or fixed point, of the Greek model of the universe was
A. the center of the galaxy. B. a point midway between the Earth and the Sun. C. the Sun's center. D. close to the Earth's center. |
D. close to the Earth's center.
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A distant asteroid is discovered that takes 50 years to orbit the Sun once. According to Kepler's third
law, what is the average distance of this asteroid from the Sun? A. 2500 AU B. 50 AU C. 353 AU (square root of 125,000) D. 13.6 AU (cube root of 2500) |
D. 13.6 AU (cube root of 2500)
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A distant asteroid is discovered that takes 50 years to orbit the Sun once. According to Kepler's third
law, what is the average distance of this asteroid from the Sun? A. 2500 AU B. 50 AU C. 353 AU (square root of 125,000) D. 13.6 AU (cube root of 2500) |
D. 13.6 AU (cube root of 2500)
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What did Galileo see when he observed Venus through his telescope?
A. Venus has an angular size, which increases and decreases markedly but does not show phases (e.g., crescent). B. Venus has phases like the Moon and, also like the Moon, is almost constant in angular size. C. Venus has phases like the Moon, and its largest angular diameter is at gibbous phase. D. Venus has phases like the Moon, and its largest angular diameter isat crescent phase. |
D. Venus has phases like the Moon, and its largest angular diameter isat crescent phase.
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Radio waves travel through space at what speed? A. much faster than the speed of light
B. at the speed of light, 3 × 108 m/s C. much slower than the speed of light D. slightly faster than the speed of light because their wavelength is longer |
B. at the speed of light, 3 × 108 m/s
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Why is the sky blue?
A. The air molecules absorb red light better than blue light, allowing more blue light to reach our eyes. B. The air molecules scatter blue light better than red light, so more blue light reaches our eyes. C. The air molecules scatter red light better than blue light, so less red light reaches our eyes. D. The air molecules absorb blue light better than red light, making the sky appear bluer. |
B. The air molecules scatter blue light better than red light, so more blue light reaches our eyes.
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Why is the sky blue?
A. The air molecules absorb red light better than blue light, allowing more blue light to reach our eyes. B. The air molecules scatter blue light better than red light, so more blue light reaches our eyes. C. The air molecules scatter red light better than blue light, so less red light reaches our eyes. D. The air molecules absorb blue light better than red light, making the sky appear bluer. |
B. The air molecules scatter blue light better than red light, so more blue light reaches our eyes.
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Comets are typically
A. gaseous bodies from which some of the gas is pushed out by the Sun to form a long tail. B. slushy mixtures of liquid and ice. C. chunks of rock that are generally a few tens of kilometers in diameter. D. chunks of ice that begin to vaporize if they pass close to the Sun. |
D. chunks of ice that begin to vaporize if they pass close to the Sun.
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Comets are typically
A. gaseous bodies from which some of the gas is pushed out by the Sun to form a long tail. B. slushy mixtures of liquid and ice. C. chunks of rock that are generally a few tens of kilometers in diameter. D. chunks of ice that begin to vaporize if they pass close to the Sun. |
D. chunks of ice that begin to vaporize if they pass close to the Sun.
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The great mountain ranges of Earth have been produced by
A. collisions between tectonic plates. B. volcanic eruptions. C. asteroid impacts because they are just worn-down crater walls. D. wrinkling of the crust as the interior cools and contracts. |
A. collisions between tectonic plates.
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The great mountain ranges of Earth have been produced by
A. collisions between tectonic plates. B. volcanic eruptions. C. asteroid impacts because they are just worn-down crater walls. D. wrinkling of the crust as the interior cools and contracts. |
A. collisions between tectonic plates.
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The chemical makeup of the central core of Earth is considered to be
A. sulfur-rich minerals compressed to a high density. B. rocky minerals rich in iron. C. almost pure iron. D. very close to the chemical makeup of the surface—silicon-rich rocks and minerals. |
C. almost pure iron.
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The chemical makeup of the central core of Earth is considered to be
A. sulfur-rich minerals compressed to a high density. B. rocky minerals rich in iron. C. almost pure iron. D. very close to the chemical makeup of the surface—silicon-rich rocks and minerals. |
C. almost pure iron.
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Spring tides occur
A. once a day. B. once a month, at full Moon. C. twice a month, at full and new Moon. D. once a year, in springtime. |
C. twice a month, at full and new Moon.
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Spring tides occur
A. once a day. B. once a month, at full Moon. C. twice a month, at full and new Moon. D. once a year, in springtime. |
C. twice a month, at full and new Moon.
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The reddish color of Mars is probably due to
A. the glow from the very high temperature surface on the sunlit parts of Mars. B. iron oxides such as rust. C. vegetation turning red in the Martian autumn. D. sulfur compounds thrown out by active volcanoes. |
B. iron oxides such as rust.
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The reddish color of Mars is probably due to
A. the glow from the very high temperature surface on the sunlit parts of Mars. B. iron oxides such as rust. C. vegetation turning red in the Martian autumn. D. sulfur compounds thrown out by active volcanoes. |
B. iron oxides such as rust.
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The approximate temperature of the visible surface of the Sun is
A. 10,000 K. B. 2000 K. C. 4300 K. D. 5800 K. |
D. 5800 K.
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The approximate temperature of the visible surface of the Sun is
A. 10,000 K. B. 2000 K. C. 4300 K. D. 5800 K. |
D. 5800 K.
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How much longer can the Sun continue to generate energy by nuclear reactions in its core?
A. about 5 million years B. about 50 billion years C. about 500,000 years D. about 5 billion years |
D. about 5 billion years
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How much longer can the Sun continue to generate energy by nuclear reactions in its core?
A. about 5 million years B. about 50 billion years C. about 500,000 years D. about 5 billion years |
D. about 5 billion years
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Star A has luminosity LA = 100 Lυ and it is 1000 pc away. Star B has the same luminosity as the Sun,
Lυ, and it is 100 pc away. What can you say about the brightnesses of these two stars? A. Star A is brighter than Star B. B. Star B is brighter than Star A. C. Star A and Star B have the same brightness. D. It is not possible to answer the question without knowing Lυ, the luminosity of the Sun. |
C. Star A and Star B have the same brightness.
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Star A has luminosity LA = 100 Lυ and it is 1000 pc away. Star B has the same luminosity as the Sun,
Lυ, and it is 100 pc away. What can you say about the brightnesses of these two stars? A. Star A is brighter than Star B. B. Star B is brighter than Star A. C. Star A and Star B have the same brightness. D. It is not possible to answer the question without knowing Lυ, the luminosity of the Sun. |
C. Star A and Star B have the same brightness.
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What are the two physical parameters of stars that are plotted in the Hertzsprung-Russell diagram?
A. mass and surface temperature B. luminosity and mass C. radius and mass D. luminosity and surface temperature |
D. luminosity and surface temperature
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A typical white dwarf has a surface temperature about four times that of the Sun and a radius about 1% that of the Sun. What can you determine about the luminosity of a typical white dwarf from this information?
A. The white dwarf will be less luminous than the Sun. B. The white dwarf and the Sun will have about the same luminosity. C. The white dwarf will be more luminous than the Sun. D. Nothing can be concluded about the relative luminosities from this information. |
A. The white dwarf will be less luminous than the Sun.
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A typical white dwarf has a surface temperature about four times that of the Sun and a radius about 1% that of the Sun. What can you determine about the luminosity of a typical white dwarf from this information?
A. The white dwarf will be less luminous than the Sun. B. The white dwarf and the Sun will have about the same luminosity. C. The white dwarf will be more luminous than the Sun. D. Nothing can be concluded about the relative luminosities from this information. |
A. The white dwarf will be less luminous than the Sun.
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How do astronomers measure the masses of stars?
A. by observing the star's brightness at different wavelengths (colors) B. by observing the motion of two stars in a binary star system C. by measuring the star's brightness, temperature, and distance D. by measuring the star's brightness and obtaining its radius using the H-R diagram |
B. by observing the motion of two stars in a binary star system
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How do astronomers measure the masses of stars?
A. by observing the star's brightness at different wavelengths (colors) B. by observing the motion of two stars in a binary star system C. by measuring the star's brightness, temperature, and distance D. by measuring the star's brightness and obtaining its radius using the H-R diagram |
B. by observing the motion of two stars in a binary star system
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At what stage of its evolutionary life is the Sun?
A. main sequence, or “middle age” B. pre–main sequence, variable star C. just before supernova stage (perhaps 5 years), late evolutionary stage D. post–main sequence, red giant (cool) phase |
A. main sequence, or “middle age”
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At what stage of its evolutionary life is the Sun?
A. main sequence, or “middle age” B. pre–main sequence, variable star C. just before supernova stage (perhaps 5 years), late evolutionary stage D. post–main sequence, red giant (cool) phase |
A. main sequence, or “middle age”
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The next stage in a star's life after the main-sequence phase is
A. the red giant phase. B. the horizontal-branch phase. C. a protostar. D. death (i.e., either a supernova or a white dwarf). |
A. the red giant phase.
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The next stage in a star's life after the main-sequence phase is
A. the red giant phase. B. the horizontal-branch phase. C. a protostar. D. death (i.e., either a supernova or a white dwarf). |
A. the red giant phase.
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The Sun will end its life by becoming a A. molecular cloud. B. black hole. C. white dwarf. D. pulsar.
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C. white dwarf.
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The Sun will end its life by becoming a A. molecular cloud. B. black hole. C. white dwarf. D. pulsar.
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C. white dwarf.
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A pulsar is a(n)
A. rapidly rotating neutron star, emitting beams of radio energy and sometimes X-ray and visible energy. B. binary star in which matter from one star is falling onto the second star. C. object at the center of each galaxy, supplying energy from its rapid rotation. D. pulsating star, in which size, temperature, and light intensity vary regularly. |
A. rapidly rotating neutron star, emitting beams of radio energy and sometimes X-ray and visible energy.
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A pulsar is a(n)
A. rapidly rotating neutron star, emitting beams of radio energy and sometimes X-ray and visible energy. B. binary star in which matter from one star is falling onto the second star. C. object at the center of each galaxy, supplying energy from its rapid rotation. D. pulsating star, in which size, temperature, and light intensity vary regularly. |
A. rapidly rotating neutron star, emitting beams of radio energy and sometimes X-ray and visible energy.
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Seasons are caused by the fact that when one hemisphere is tilted towards the Sun, it is closer to the Sun, and therefore warmer.True False
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False Correct. While the tilt affects the seasons, the difference in distance between the closer side and the farther side is negligible compared to the distance between the Sun and Earth. The tilt causes a variation in the length of day and the directness of the Sun's rays, which causes the seasons.
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The Sun is directly overhead for people living on the equator exactly twice a year, on the equinoxes.
True False |
True Correct. The dates of the equinoxes are defined as the dates when the Sun is directly over Earth's equator.
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For people living in the continental United States, you would face _____ to look directly at the Sun at noon on the summer solstice.
North South East West Overhead |
South
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When do people in Sydney, Australia observe the Sun above the horizon for the longest period of time (i.e., when are their days the longest)?
Around December 21. When the United States experiences their shortest day of the year. When the Sun is highest in their sky at noon. On their first day of summer. All of the above. |
All of the above. Correct. In the southern hemisphere, the longest day occurs on December 21, the first day of their summer, when the Sun is highest in the sky at noon for them. This is just the opposite for us in the U.S.A.
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After a long night of partying, one of your friends yells "Road Trip!" You all hop in the car and keep driving. When you finally reach your destination it is noon and you see the Sun directly overhead. You look at the calendar and see that it is December 21st. At what latitude are you?
The Arctic Circle (66.5° N) The Tropic of Cancer (23.5° N) The Equator The Tropic of Capricorn (23.5° S) The Antarctic Circle (66.5° S) |
The Tropic of Capricorn (23.5° S) Correct. On December 21 the Sun is farthest away from the celestial equator in the southern hemisphere, 23.5° away. To view it directly overhead, you would have to be at a latitude of 23.5° S.
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In ancient Greece, the philosopher Aristotle put forth the idea that
A. the universe is governed by regular laws. B. the Sun is the center of the solar system. C. Earth is only one of hundreds of planets scattered throughout the galaxy. D. gravitation keeps the planets in their orbits. |
A. the universe is governed by regular laws.
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Planets move past the background stars as seen by someone on the Earth. What is the normal direction of this motion?
A. east to west because of the rotation of the Earth B. east to west because of the motion of the planet along its orbit C. west to east because of the motion of the Earth along its orbit D. west to east because of the motion of the planet along its orbit |
D. west to east because of the motion of the planet along its orbit
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The term retrograde motion for a planet refers to the
A. temporary reversal of the planet's normal east-to-west motion past the background stars as seen from the Earth. B. apparent motion of a planet's moon in the opposite direction to the motion of the planet itself during half of each orbit of the moon around the planet. C. temporary reversal of a planet's direction of spin about its axis of rotation. D. temporary reversal of the planet's normal west-to-east motion past the background stars as seen from the Earth. |
D. temporary reversal of the planet's normal west-to-east motion past the background stars as seen from the Earth.
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The term retrograde motion for a planet refers to the
A. temporary reversal of the planet's normal east-to-west motion past the background stars as seen from the Earth. B. apparent motion of a planet's moon in the opposite direction to the motion of the planet itself during half of each orbit of the moon around the planet. C. temporary reversal of a planet's direction of spin about its axis of rotation. D. temporary reversal of the planet's normal west-to-east motion past the background stars as seen from the Earth. |
D. temporary reversal of the planet's normal west-to-east motion past the background stars as seen from the Earth.
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Ptolemy's model for the solar system was
A. Earth-centered, with the Sun, the Moon, and the planets moving in ellipses in the sky. B. Sun-centered, with elliptical planetary orbits. C. Sun-centered, with the planets moving in circles around it. D. Earth-centered, with planetary orbits composed of deferents and epicycles. |
D. Earth-centered, with planetary orbits composed of deferents and epicycles.
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The Copernican system for planetary motions is
A. Earth-centered, with the planets, the Sun, and the stars mounted on crystal spheres, pivoted to allow the correct motions around the Earth. B. Earth-centered, with the planets moving in epicycles around the Earth. C. Sun-centered, with the planets moving in elliptical orbits and the Sun at one focus of the ellipse. D. Sun-centered, with the planets moving in perfect circles around the Sun. |
D. Sun-centered, with the planets moving in perfect circles around the Sun.
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The observation by Tycho Brahe of a supernova in 1572 was significant because it
A. showed a parallax (relative apparent motion) that proved it to be more distant than the Moon. B. showed motion in a circular orbit. C. proved Kepler's three laws. D. proved the heliocentric theory. |
A. showed a parallax (relative apparent motion) that proved it to be more distant than the Moon.
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A perfect circle is an ellipse with an eccentricity of
A. zero. B. one. C. pi. D. infinity. |
A. zero.
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A perfect circle is an ellipse with an eccentricity of
A. zero. B. one. C. pi. D. infinity. |
A. zero.
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If the line joining a planet to the Sun sweeps out a particular area in 1 day, then in 2 days it will sweep out
A. less than twice the area if the planet is approaching perihelion and more than twice the area if it is leaving perihelion. B. half the area. C. more than twice the area if the planet is approaching perihelion and less than twice the area if it is leaving perihelion. D. exactly twice the area. |
D. exactly twice the area.
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A space probe is put into a circular orbit around the Sun at a distance of exactly 2 AU from the Sun. According to Kepler's third law, how long does it take this probe to orbit the Sun once?
A. 1.6 years (cube root of 4) B. 1 year C. 8 years D. 2.8 years (square root of 8) |
D. 2.8 years (square root of 8)
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A distant asteroid is discovered that takes 50 years to orbit the Sun once. According to Kepler's third law, what is the average distance of this asteroid from the Sun?
A. 2500 AU B. 50 AU C. 353 AU (square root of 125,000) D. 13.6 AU (cube root of 2500) |
D. 13.6 AU (cube root of 2500)
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1 AU, or 1 astronomical unit, is defined as the
A. distance at which the Earth-Sun distance will subtend an angle of 1 arc second. B. mean distance between the Sun and the Earth. C. radius of the Sun. D. distance traveled by light in 1 year. |
B. mean distance between the Sun and the Earth.
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A planet does not change its speed as it orbits the Sun.
True False |
False Correct. Kepler's second law tells us that a planet travels much faster at perihelion than at aphelion.
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In our Solar System, most planetary orbits have eccentricities that are approximately equal to:
0 0.5 0.75 1.0 |
Correct. In the Solar System, planetary orbits are very close to 0; Mercury is the highest with an eccentricity of 0.206.
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In our Solar System, most planetary orbits have eccentricities that are approximately equal to:
0 0.5 0.75 1.0 |
0 Correct. In the Solar System, planetary orbits are very close to 0; Mercury is the highest with an eccentricity of 0.206.
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The average distance of a planet from the Sun is given by which orbital property?
semimajor axis semiminor axis eccentricity period |
semimajor axis Correct. The semimajor axis, half of the long axis of the ellipse, is also the average distance of the planet from the Sun.
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The Earth is 1 AU from the Sun and has a period of 1 year. What would be the period for an imaginary planet located at 2 AU from the Sun?
1 year. 2 years. between 2-3 years. more than 3 years. |
between 2-3 years.Correct. 2 cubed (2 x 2 x 2) is 8, and the square root of 8 is about 2.8.
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The Earth is 1 AU from the Sun and has a period of 1 year. What would be the period for an imaginary planet located at 2 AU from the Sun?
1 year. 2 years. between 2-3 years. more than 3 years. |
between 2-3 years.Correct. 2 cubed (2 x 2 x 2) is 8, and the square root of 8 is about 2.8.
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Which is the correct form of Kepler's third law?
P2 a2 P3 a2 P2 a3 P3 a3 |
P2 a3 Correct. Kepler found that the square of the period was proportional to the cube of the semimajor axis.
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What was the material from which the solar system formed?
A. nebula made mostly of heavy elements but enriched in hydrogen and helium from supernova explosions B. debris from the explosion of a massive star C. nebula made entirely of hydrogen and helium gas D. nebula made mostly of hydrogen and helium gas but enriched in heavier elements from supernova explosions |
D. nebula made mostly of hydrogen and helium gas but enriched in heavier elements from supernova explosions
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The average density of which of the following planetary groups is close to that of water (1000 kg/m3)?
A. Mercury and Venus because they are close to the Sun B. terrestrial planets because they are of relatively low mass and have been compressed very little by gravitational forces C. asteroids because they are very small objects D. large, outer planets because of their composition, hydrogen and helium |
D. large, outer planets because of their composition, hydrogen and helium
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The major constituents of Earth's atmosphere are
A. 95% carbon dioxide and some water vapor. B. about equal amounts of methane, ammonia, water vapor, and carbon dioxide, C. 77% oxygen and 21% nitrogen. D. 77% nitrogen and 21% oxygen. |
D. 77% nitrogen and 21% oxygen.
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The large amount of free oxygen in Earth's present atmosphere is primarily a result of
A. out-gassing by volcanoes and other geological processes. B. biological processes such as photosynthesis. C. splitting of carbon dioxide into carbon and oxygen by solar ultraviolet light. D. carbon dioxide becoming dissolved in the oceans, releasing oxygen. |
B. biological processes such as photosynthesis.
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Ozone in the stratosphere performs an important task that protects life on Earth. What is it?
A. Ozone absorbs the solar wind as it streams into Earth, thereby protecting life from dangerous ionizing radiation. B. Ozone absorbs much of the dangerous solar ultraviolet light. C. Ozone acts as a disinfectant, killing dangerous viruses and bacteria that drift in all the time from space before they can reach Earth. D. Ozone absorbs infrared radiation, thereby providing a comfortable atmospheric temperature on the surface of Earth. |
B. Ozone absorbs much of the dangerous solar ultraviolet light.
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In which layer of Earth's atmosphere is the ozone layer located?
A. mesosphere B. stratosphere C. thermosphere D. troposphere |
B. stratosphere
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On Earth, the majority of earthquakes occur
A. along regions of greatest thermal stress in arctic and antarctic regions. B. in the centers of tectonic plates (e.g., North American continent). C. along the boundaries of major tectonic plates. D. along the zone of maximum tidal stress around the equator. |
C. along the boundaries of major tectonic plates.
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Earth's magnetic field protects Earth and its inhabitants from
A. the high-energy cosmic rays or hydrogen nuclei moving through our universe. B. the majority of tiny but high-speed micrometeorites, which otherwise would crater Earth and cause significant damage to property. C. a significant proportion of the solar neutrinos, the enormous flux of which could otherwise produce damage to genetic material in life forms. D. the solar wind, which would otherwise irradiate and damage life forms if not deflected. |
D. the solar wind, which would otherwise irradiate and damage life forms if not deflected.
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Earth's magnetic field protects Earth and its inhabitants from
A. the high-energy cosmic rays or hydrogen nuclei moving through our universe. B. the majority of tiny but high-speed micrometeorites, which otherwise would crater Earth and cause significant damage to property. C. a significant proportion of the solar neutrinos, the enormous flux of which could otherwise produce damage to genetic material in life forms. D. the solar wind, which would otherwise irradiate and damage life forms if not deflected. |
D. the solar wind, which would otherwise irradiate and damage life forms if not deflected.
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Where are Earth's Van Allen radiation belts located?
A. in the magnetosphere B. in the stratosphere C. in the molten iron core D. in the atmosphere above the auroral regions, centered over the north and south magnetic poles |
A. in the magnetosphere
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Auroras on Earth are caused by
A. reflection of sunlight from the Arctic and Antarctic ice into the polar skies. B. electrons accelerated by electric currents in the ionosphere and then deposited into Earth's atmosphere. C. high-energy charged particles from the magnetosphere guided by Earth's magnetic field into polar regions of the atmosphere. D. ultraviolet radiation from the Sun exciting and ionizing atoms in Earth's upper atmosphere to emit characteristic colors of light. |
C. high-energy charged particles from the magnetosphere guided by Earth's magnetic field into polar regions of the atmosphere.
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Auroras on Earth are caused by
A. reflection of sunlight from the Arctic and Antarctic ice into the polar skies. B. electrons accelerated by electric currents in the ionosphere and then deposited into Earth's atmosphere. C. high-energy charged particles from the magnetosphere guided by Earth's magnetic field into polar regions of the atmosphere. D. ultraviolet radiation from the Sun exciting and ionizing atoms in Earth's upper atmosphere to emit characteristic colors of light. |
C. high-energy charged particles from the magnetosphere guided by Earth's magnetic field into polar regions of the atmosphere.
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Earthquakes are an important tool for understanding the Earth because they are the only way we have to get detailed information about the layers inside the Earth.
True False |
True. Yes! Seismic waves provide information about differing densities between layers and whether material is in the solid or liquid state.
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There are three types of earthquake waves (P waves, S waves, and surface waves), and all three of them travel through the interior of the Earth.
True False |
FalseYes! Only S and P waves move through the Earth's interior regions.
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A seismograph is a graph of data from a seismometer. The graph has time on the x-axis and ______________ on the y-axis.
temperature movement of the Earth velocity pressure |
movement of the EarthCorrect! Regions inside the Earth are displaced as the wave propagates over time.
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Every earthquake has a "shadow zone" on the opposite side of the Earth in which no earthquake waves are visible in seismographs. This shadow zone occurs because:
Earth's outer core is liquid and does not support P waves. Some earthquakes do not produce any waves. Earthquake waves are bent at the core-mantle boundary. |
Earthquake waves are bent at the core-mantle boundary.Correct! The waves are refracted due to greatly differing densities of the core and mantle, causing them to miss some seismometers on the surface.
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Every earthquake has a "shadow zone" on the opposite side of the Earth in which no earthquake waves are visible in seismographs. This shadow zone occurs because:
Earth's outer core is liquid and does not support P waves. Some earthquakes do not produce any waves. Earthquake waves are bent at the core-mantle boundary. |
Earthquake waves are bent at the core-mantle boundary.Correct! The waves are refracted due to greatly differing densities of the core and mantle, causing them to miss some seismometers on the surface.
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We know from earthquake wave studies that Earth's outer core is made of:
rocks like those we see at the surface. a liquid. a single crystal of iron. radioactive isotopes. |
a liquid.Correct! The S waves cannot propagate through liquids.
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We know from earthquake wave studies that Earth's outer core is made of:
rocks like those we see at the surface. a liquid. a single crystal of iron. radioactive isotopes. |
a liquid.Correct! The S waves cannot propagate through liquids.
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Mercury's atmosphere is
A. almost nonexistent. B. relatively dense, composed mostly of nitrogen (80%) and oxygen (20%). C. very thin, made up of sulfur dioxide and hydrogen sulfide from volcanoes. D. relatively thin, composed of carbon dioxide with small quantities of nitrogen and argon. |
A. almost nonexistent.
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The gas that is the major constituent of the atmospheres of Venus and Mars and a minor constituent of the Earth's atmosphere is
A. oxygen. B. water. C. carbon dioxide. D. nitrogen. |
C. carbon dioxide
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Tomorrow's weather report for Venus would be
A. overcast and very hot. B. cold and clear. C. snow. D. hot and humid, with clear skies. |
A. overcast and very hot.
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Tomorrow's weather report for Venus would be
A. overcast and very hot. B. cold and clear. C. snow. D. hot and humid, with clear skies. |
A. overcast and very hot.
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What is the main reason that the greenhouse effect has been much more effective in raising the surface temperature on Venus than in raising the surface temperature on the Earth?
A. The solar wind, the major cause of heating in the greenhouse effect, is far more intense at Venus's distance from the Sun, and Venus has no magnetic field to deflect this solar wind. B. Carbon dioxide, which traps heat from the planet's surface, is the major component in the very dense Venusian atmosphere, while it is a only a minor constituent of the Earth's. C. The oceans on Earth have acted as a thermostat in absorbing much of the heat that would otherwise have raised the Earth's temperature significantly D. The surface of Venus is much more effective than the surface of the Earth in absorbing solar visible and UV radiation |
B. Carbon dioxide, which traps heat from the planet's surface, is the major component in the very dense Venusian atmosphere, while it is a only a minor constituent of the Earth's.
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The reddish color of Mars is probably due to
A. the glow from the very high temperature surface on the sunlit parts of Mars. B. iron oxides such as rust. C. vegetation turning red in the Martian autumn. D. sulfur compounds thrown out by active volcanoes. |
B. iron oxides such as rust.
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The reddish color of Mars is probably due to
A. the glow from the very high temperature surface on the sunlit parts of Mars. B. iron oxides such as rust. C. vegetation turning red in the Martian autumn. D. sulfur compounds thrown out by active volcanoes. |
B. iron oxides such as rust.
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Mars experiences similar seasonal changes to those on the Earth because
A. its has about the same shape of elliptical orbit as the Earth, which produces similar changes in solar radiation intensity as the planet orbits the Sun. B. its spin axis is tilted at about the same angle to its orbital plane as is the Earth's axis. C. the length of its day is very close to the length of an Earth day. D. the length of its year is very close to that of the Earth. |
B. its spin axis is tilted at about the same angle to its orbital plane as is the Earth's axis.
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Mars experiences similar seasonal changes to those on the Earth because
A. its has about the same shape of elliptical orbit as the Earth, which produces similar changes in solar radiation intensity as the planet orbits the Sun. B. its spin axis is tilted at about the same angle to its orbital plane as is the Earth's axis. C. the length of its day is very close to the length of an Earth day. D. the length of its year is very close to that of the Earth. |
B. its spin axis is tilted at about the same angle to its orbital plane as is the Earth's axis.
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On which planetary body can distinct evidence be seen for the flow of water at an earlier time?
A. Mars B. Earth's Moon C. Venus D. Titan, the moon of Saturn |
A. Mars
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The existence of the Great Red Spot of Jupiter has been known since
A. the arrival at Jupiter of Voyager 1, with its imaging cameras, in 1979. B. the time of Hooke and Cassini in the 1600s. C. first light at the 200-inch telescope on Mount Palomar, in 1948. D. the first fly-by of a spacecraft, Pioneer 10, in December 1973. |
B. the time of Hooke and Cassini in the 1600s.
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The material in the interior of Jupiter that is thought to be responsible for its powerful magnetic field is
A. solid magnetic and magnetized iron. B. liquid metallic hydrogen. C. “ices” of NH3 (ammonia), CH4 (methane), and H2O (water) that contain frozen-in magnetic fields. D. molten iron and nickel. |
B. liquid metallic hydrogen.
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The cause of the “meteor showers” seen at regular times each year on Earth is most probably
A. Earth running into material within the spiral arm structure of the Milky Way. B. unstable weather conditions on Earth. C. Earth moving through the remnant dust and rock fragments of an old comet that are orbiting the Sun in the comet's old orbit. D. sunspot activity and the resultant geomagnetic disturbances. |
C. Earth moving through the remnant dust and rock fragments of an old comet that are orbiting the Sun in the comet's old orbit.
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The nucleus of a comet would easily fit within the Earth.
True False |
True You are right. The nucleus is typically 10-15 km in diameter.
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The greatest number of cometary orbits have eccentricities of approximately:
0 0.2 0.5 0.9 |
0.9Correct. Cometary orbits are highly eccentric, with eccentricities of 0.92-0.99 being most common.
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When a comet is at perihelion, which of its components is closest in size to the diameter of the Sun?
The nucleus The coma The ion tail The dust tail The hydrogen envelope |
The comaWell done! The coma is roughly 75% of the Sun's diameter. The nucleus is much smaller, while the tails and hydrogen envelope are much larger.
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Using a high-grade amateur telescope, you are lucky enough to observe a comet in the sky. To you, it looks like a bright white ball with a blue streak extending behind it. You correctly identify the blue streak as the:
nucleus coma ion tail dust tail hydrogen envelope |
ion tailThat's true. The ion tail glows blue due to emission from carbon molecules.
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At aphelion, a comet consists of:
A nucleus only A nucleus and the coma A nucleus, the coma and the tails A nucleus, the coma, the tails, and the hydrogen envelope. |
A nucleus only Correct. Far from the Sun, only the nucleus remains.
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Galileo Galilei, an Italian scientist, was the first person known to use a telescope to study the sky.
True False |
True
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Jupiter's moons were known to the ancient Greeks, but they did not know what they were.
True False |
False
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Sometimes one or more of Jupiter's moons pass behind Jupiter.
True False |
True
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Sometimes one or more of Jupiter's moons pass behind Jupiter.
True False |
True
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Moons appear to move faster when they appear closer to Jupiter. But each moon really has about the same speed everywhere in its orbit; the apparent difference is caused by the fact that we view the orbits from the side.
True False |
True
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Io orbits faster than any of the other moons - it takes less than 2 days for Io to make a complete orbit.
True False |
True
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Io orbits faster than any of the other moons - it takes less than 2 days for Io to make a complete orbit.
True False |
True
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When we look at Jupiter from Earth, Io always appears closest to the planet, and Callisto always appears the farthest.
True False |
False
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How long did Galileo watch the moons before he realized they were orbiting Jupiter?
A few hours 1 night 8 nights 3 years |
8 nights
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Put the four Galilean moons in order of increasing speed of their orbits around Jupiter:
Io, Europa, Ganymede, Callisto Ganymede, Io, Callisto, Europa Callisto, Io, Europa, Ganymede Callisto, Ganymede, Europa, Io |
Callisto, Ganymede, Europa, Io
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When Galileo first saw the moons of Jupiter, what did he think they were?
moons stars planets asteroids |
stars
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Which of the following was an important effect that Galileo's observations of the moons of Jupiter had on astronomy?
His observation that the moons orbited Jupiter helped convince astronomers that Copernicus's Sun-centered model made better predictions than Earth-centered models. His discovery of volcanoes on Io showed that volcanoes could be found in many places other than Earth. His careful measurements led to the first accurate estimate of the speed of light. His orbital measurements led to a more precise version of Newton's Law of Universal Gravitation. |
His observation that the moons orbited Jupiter helped convince astronomers that Copernicus's Sun-centered model made better predictions than Earth-centered models.
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When light passes through a prism of glass,
A. the prism absorbs colors from different parts of the broad beam coming out of the prism, leaving the complementary colors that we see. B. different colors are caused by multiple reflections within the prism and the resulting interference between the beams. C. refraction changes the directions of different colors or wavelengths of light. D. the prism adds colors to different parts of the outgoing and broadly scattered beam. |
C. refraction changes the directions of different colors or wavelengths of light.
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When light passes through a prism of glass,
A. the prism absorbs colors from different parts of the broad beam coming out of the prism, leaving the complementary colors that we see. B. different colors are caused by multiple reflections within the prism and the resulting interference between the beams. C. refraction changes the directions of different colors or wavelengths of light. D. the prism adds colors to different parts of the outgoing and broadly scattered beam. |
C. refraction changes the directions of different colors or wavelengths of light.
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Visible wavelengths of electromagnetic radiation have a range of wavelengths of
A. 400 nm to 700 nm. B. 1 nm to 100 nm. C. 800 nm to 1900 nm. D. 90 nm to 130 nm. |
A. 400 nm to 700 nm.
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Visible wavelengths of electromagnetic radiation have a range of wavelengths of
A. 400 nm to 700 nm. B. 1 nm to 100 nm. C. 800 nm to 1900 nm. D. 90 nm to 130 nm. |
A. 400 nm to 700 nm.
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All forms of light have what property in common?
A. All forms of light are electromagnetic radiation. B. All forms of light have the same wavelength. C. All forms of light are ultrasonic radiation. D. All forms of light have wavelengths between 400 nm and 700 nm. |
A. All forms of light are electromagnetic radiation.
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All forms of light have what property in common?
A. All forms of light are electromagnetic radiation. B. All forms of light have the same wavelength. C. All forms of light are ultrasonic radiation. D. All forms of light have wavelengths between 400 nm and 700 nm. |
A. All forms of light are electromagnetic radiation.
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Which of the following types of electromagnetic radiation has the longest wavelength?
A. radio waves B. ultraviolet light C. infrared radiation D. microwaves |
A. radio waves
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What is the magnification of a Newtonian telescope that has a primary mirror of diameter 0.25 m and focal length of 2 m when used with an eyepiece of focal length 25 mm and an optical diameter of 5 mm?
A. 50 times B. 10 times C. 80 times D. 400 times |
C. 80 times
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What is the magnification of a Newtonian telescope that has a primary mirror of diameter 0.25 m and focal length of 2 m when used with an eyepiece of focal length 25 mm and an optical diameter of 5 mm?
A. 50 times B. 10 times C. 80 times D. 400 times |
C. 80 times
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In general, doubling the diameter of an optical telescope will
A. quadruple the light-gathering power and double the angular resolution. B. quadruple the light-gathering power and quadruple the angular resolution. C. double both the light-gathering power and the angular resolution. D. double the light-gathering power and quadruple the angular resolution. |
A. quadruple the light-gathering power and double the angular resolution.
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How does angular resolution for a given diameter of telescope depend on wavelength?
A. Angular resolution worsens as wavelength increases. B. Angular resolution may improve or worsen as wavelength increases, depending on other factors such as intensity and spectral range (e.g., optical, infrared, radio). C. Angular resolution improves as wavelength increases. D. Angular resolution depends only on the diameter of the telescope and is independent of wavelength. |
A. Angular resolution worsens as wavelength increases.
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How does angular resolution for a given diameter of telescope depend on wavelength?
A. Angular resolution worsens as wavelength increases. B. Angular resolution may improve or worsen as wavelength increases, depending on other factors such as intensity and spectral range (e.g., optical, infrared, radio). C. Angular resolution improves as wavelength increases. D. Angular resolution depends only on the diameter of the telescope and is independent of wavelength. |
A. Angular resolution worsens as wavelength increases.
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The specific colors of light emitted by an atom in a hot, thin gas (e.g., in a neon tube, a fluorescent bulb, or a gas cloud in space) are caused by
A. an electron dropping into the nucleus, producing small nuclear changes. B. electrons jumping to lower energy levels, losing energy as they do so. C. protons jumping from level to level. D. vibrations of the electrons within the atom. |
B. electrons jumping to lower energy levels, losing energy as they do so.
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The basic makeup of an atom is
A. small negatively charged particles orbiting around a central positive charge. B. negative and positive charges mixed uniformly through the volume of the atom. C. miniature planets, possibly with miniature people, gravitationally bound in orbits around a miniature star. D. small positively charged particles orbiting around a central negative charge. |
A. small negatively charged particles orbiting around a central positive charge.
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The basic makeup of an atom is
A. small negatively charged particles orbiting around a central positive charge. B. negative and positive charges mixed uniformly through the volume of the atom. C. miniature planets, possibly with miniature people, gravitationally bound in orbits around a miniature star. D. small positively charged particles orbiting around a central negative charge. |
A. small negatively charged particles orbiting around a central positive charge.
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The average distance of Pluto from the Sun is 40 AU. How long does it take for light to travel across the solar system from one side of Pluto's orbit to the other?
A. 5 hours B. 8 minutes C. 22 hours D. 11 hours |
D. 11 hours
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The average distance of Pluto from the Sun is 40 AU. How long does it take for light to travel across the solar system from one side of Pluto's orbit to the other?
A. 5 hours B. 8 minutes C. 22 hours D. 11 hours |
D. 11 hours
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Considering the whole electromagnetic spectrum, visible light dominates the entire spectrum.
True False |
FalseCorrect. Visible light is actually a very small portion of the electromagnetic spectrum.
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Gamma rays are the most energetic kind of electromagnetic radiation.
True False |
TrueCorrect. Gamma rays have the greatest energy, shortest wavelength, and highest frequency of any form of electromagnetic radiation.
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As the wavelength of electromagnetic radiation increases, the
frequency increases and energy decreases. frequency increases and energy increases. frequency decreases and energy decreases. frequency decreases and energy increases. |
frequency decreases and energy decreases.Correct. Wavelength and frequency are inversely proportional - when one increases, the other decreases. Wavelength and energy are also inversely proportional - when one goes up (increases), the other goes down (decreases).
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As the wavelength of electromagnetic radiation increases, the
frequency increases and energy decreases. frequency increases and energy increases. frequency decreases and energy decreases. frequency decreases and energy increases. |
frequency decreases and energy decreases.Correct. Wavelength and frequency are inversely proportional - when one increases, the other decreases. Wavelength and energy are also inversely proportional - when one goes up (increases), the other goes down (decreases).
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Herschel detected ________beyond the red visible portion of the spectrum.
Ultraviolet radiation. Radio waves X-rays Infrared radiation |
Infrared radiation Correct. The invisible region of the spectrum closest to red light is infrared - slightly longer wavelength than red visible light.
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Herschel detected ________beyond the red visible portion of the spectrum.
Ultraviolet radiation. Radio waves X-rays Infrared radiation |
Infrared radiation Correct. The invisible region of the spectrum closest to red light is infrared - slightly longer wavelength than red visible light.
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An inverse relationship between two variables means that when one variable increases, the other
Decreases. Increases. Stays the same. |
DecreasesCorrect. An example would be the relationship between wavelength and energy.
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Each chemical element produces a unique emission or bright-lined spectrum
True False |
TrueCorrect. This is true, since the unique electron structure of each element results in a unique spectrum.
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A hot dense gas produces a dark-lined absorption spectrum.
True False |
FalseCorrect. This is false, since a hot dense gas, like a hot solid, gives off a continuous spectrum.
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Red stars are always hotter than yellow stars. True False.
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FalseCorrect. This is false. As any object gets hotter, its peak wavelength shifts toward the blue.
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Comparing the spectra for a blue star and a red star of equal size, the blue star
Produces much more energy. Produces much less energy. Produces the same amount of energy. |
Produces much more energy.Correct. A blue star has a higher temperature, and so produces much more energy, as described by the Stefan-Boltzmann law F = σT4.
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In the emission spectrum for sodium, two bright yellow lines are visible. As the temperature of the sodium increases, these lines
Remain the same in intensity. Increase in intensity. Decrease in intensity. |
Increase in intensity.Correct. You observed the emission lines increasing in intensity in the first 'Background' animation.
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The average temperature of Mars is lower than that of Venus. If an observer measures the spectrum of infrared radiation coming from each planet, what would she discover ?
The spectrum of infrared emission for both planets is identical. The spectrum of infrared emission for both planets reach the same maximum wavelength, but is more intense for Venus. The spectrum of infrared emission for Venus would be most intense at a shorter wavelength. The spectrum of infrared emission for Venus would be most intense at a longer wavelength. |
The spectrum of infrared emission for Venus would be most intense at a shorter wavelength.Correct. The hotter object, Venus, would be most intense at shorter wavelengths, as described by Wien's law, λmax = 0.0029 K⋅m/T
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Some stars have no atmosphere. The light emerging from its surface would still have the typical stellar absorption line spectrum.
True False |
False.Correct. This is false. The light would be a continuous spectrum from a hot, dense object. There would be no cooler, absorbent layer to absorb any of its light.
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A star having a temperature of 3000K emits mostly
Radio waves. Infrared radiation. Visible light. Ultraviolet radiation. |
Infrared radiation.Correct. This is a cooler star than the Sun, which is emitting mostly in the visible from a surface temperature of 5800 K.
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The Sun's spectrum, as observed from Earth, is classified as
Absorption. Continuous Emission |
AbsorptionCorrect. Light from the Sun's continuous spectrum is absorbed first by the Sun's cooler atmosphere, and then again by the much cooler atmosphere of Earth.
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The approximate temperature of the visible surface of the Sun is
A. 10,000 K. B. 2000 K. C. 4300 K. D. 5800 K. |
D. 5800 K.
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The granular appearance of the surface of the Sun is evidence of what phenomenon occurring in or on the Sun?
A. cells of thermonuclear fusion just under the visible surface B. rapid rotation of the surface layers producing swirls of gas C. concentration and heating of ionized gas by regions of high magnetic fields D. convective motion under the solar surface |
D. convective motion under the solar surface
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What is the corona on the Sun?
A. Sun's inner atmosphere, just above the photosphere B. large region beyond (outside of) the Sun's atmosphere, filled with solar wind C. region above the solar north and south poles, the Sun's “crown” D. Sun's outer atmosphere |
D. Sun's outer atmosphere
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Sunspots are
A. cooler, darker regions on the Sun's surface. B. the shadows of cool, dark clouds of matter hanging above the solar surface. C. cooler regions of the Sun's high corona. D. hotter, deeper regions in the Sun's atmosphere. |
A. cooler, darker regions on the Sun's surface.
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What is the average length of time from one maximum in the number of sunspots on the Sun to the next maximum?
A. 22 years B. 7 years C. 11 years D. 4 years |
C. 11 years
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What is the lifetime of a typical sunspot?
A. from a few hours to a few months B. here today, gone tomorrow! C. 11 years D. from a few years to a few decades |
A. from a few hours to a few months
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What is the lifetime of a typical sunspot?
A. from a few hours to a few months B. here today, gone tomorrow! C. 11 years D. from a few years to a few decades |
A. from a few hours to a few months
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What is the rotation period of the Sun?
A. about two rotations per year B. about one rotation per day C. about four rotations per month D. about one rotation per month |
D. about one rotation per month
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The dominant energy source that powers the Sun at the present time is
A. the release of gravitational energy as the Sun slowly contracts. B. thermonuclear fusion of hydrogen into helium in the core. C. thermonuclear fission of helium into hydrogen in the core. D. thermonuclear fusion of helium into heavier elements in the core. |
B. thermonuclear fusion of hydrogen into helium in the core.
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A particular star has an angle of parallax of 0.2 arcsecond. What is the distance to this star?
A. 50 pc B. 2 pc C. 5 pc D. 0.2 pc |
C. 5 pc
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Apparent magnitude is a measure of a star's
A. intrinsic brightness (actual light output). B. size (diameter). C. temperature. D. brightness, as seen from Earth. |
D. brightness, as seen from Earth.
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Apparent magnitude is a measure of a star's
A. intrinsic brightness (actual light output). B. size (diameter). C. temperature. D. brightness, as seen from Earth. |
D. brightness, as seen from Earth.
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A star of apparent magnitude +3.5 appears _____ than a star of apparent magnitude +3.3.
A. farther away B. fainter. C. either brighter or fainter, depending on the distance to the stars D. brighter |
B. fainter.
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A star's absolute magnitude and its apparent magnitude have the same numerical value. How far is this star from Earth?
A. It is not possible for a star to have the same absolute and apparent magnitudes. B. The star would have to be an infinite distance away. C. 10 ly D. 10 pc |
D. 10 pc
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A star's absolute magnitude and its apparent magnitude have the same numerical value. How far is this star from Earth?
A. It is not possible for a star to have the same absolute and apparent magnitudes. B. The star would have to be an infinite distance away. C. 10 ly D. 10 pc |
D. 10 pc
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How many times brighter is a star with an apparent magnitude of +1.0 than a star with an apparent magnitude of +6.0?
A. 100 times brighter B. 5 times brighter C. The question is incorrectly worded; the magnitude +6 star will be 100 times brighter than the magnitude +1 star. D. 2.512 times brighter. |
A. 100 times brighter
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Star A has luminosity LA = 100 Lυ and it is 1000 pc away. Star B has the same luminosity as the Sun, Lυ, and it is 100 pc away. What can you say about the brightnesses of these two stars?
A. Star A is brighter than Star B. B. Star B is brighter than Star A. C. Star A and Star B have the same brightness. D. It is not possible to answer the question without knowing Lυ, the luminosity of the Sun. |
C. Star A and Star B have the same brightness.
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Star A has luminosity LA = 100 Lυ and it is 1000 pc away. Star B has the same luminosity as the Sun, Lυ, and it is 100 pc away. What can you say about the brightnesses of these two stars?
A. Star A is brighter than Star B. B. Star B is brighter than Star A. C. Star A and Star B have the same brightness. D. It is not possible to answer the question without knowing Lυ, the luminosity of the Sun. |
C. Star A and Star B have the same brightness.
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Suppose that, at night, the distance between an observer and a lightbulb is doubled. How does its final brightness compare with its initial brightness?
A. The lightbulb appears 1/16 as bright. B. The lightbulb appears 4 times brighter. C. The lightbulb appears 1/2 as bright. D. The lightbulb appears 1/4 as bright. |
D. The lightbulb appears 1/4 as bright.
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Suppose that, at night, the distance between an observer and a lightbulb is doubled. How does its final brightness compare with its initial brightness?
A. The lightbulb appears 1/16 as bright. B. The lightbulb appears 4 times brighter. C. The lightbulb appears 1/2 as bright. D. The lightbulb appears 1/4 as bright. |
D. The lightbulb appears 1/4 as bright.
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The spectrum of an ordinary main-sequence star is a
A. continuum of colors, crossed by brighter lines caused by emission from the hot atoms and molecules on the star's surface. B. smooth continuum of color, peaking at a specific wavelength whose position depends on the star's surface temperature. C. series of emission lines, mostly from hydrogen, the major constituent of stellar surfaces, that occasionally overlap to produce sections of continous color. D. continuum of colors crossed by dark absorption lines caused by absorption by cooler atoms and molecules at the star's surface. |
D. continuum of colors crossed by dark absorption lines caused by absorption by cooler atoms and molecules at the star's surface.
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The spectrum of an ordinary main-sequence star is a
A. continuum of colors, crossed by brighter lines caused by emission from the hot atoms and molecules on the star's surface. B. smooth continuum of color, peaking at a specific wavelength whose position depends on the star's surface temperature. C. series of emission lines, mostly from hydrogen, the major constituent of stellar surfaces, that occasionally overlap to produce sections of continous color. D. continuum of colors crossed by dark absorption lines caused by absorption by cooler atoms and molecules at the star's surface. |
D. continuum of colors crossed by dark absorption lines caused by absorption by cooler atoms and molecules at the star's surface.
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What are the two physical parameters of stars that are plotted in the Hertzsprung-Russell diagram?
A. mass and surface temperature B. luminosity and mass C. radius and mass D. luminosity and surface temperature |
D. luminosity and surface temperature
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What are the two physical parameters of stars that are plotted in the Hertzsprung-Russell diagram?
A. mass and surface temperature B. luminosity and mass C. radius and mass D. luminosity and surface temperature |
D. luminosity and surface temperature
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In the Hertzsprung-Russell diagram in Figure 11-7 of Comins and Kaufmann, Discovering the Universe, 8th ed., which of the following lists is the correct sequence of stars in order of increasing temperature?
A. Sirius B, Deneb, Procyon B, the Sun B. Deneb, the Sun, Sirius B, Procyon B C. Sun, Procyon B, Deneb, Sirius B D. Procyon B, Sirius B, the Sun, Deneb |
C. Sun, Procyon B, Deneb, Sirius B
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In the Hertzsprung-Russell diagram in Figure 11-7 of Comins and Kaufmann, Discovering the Universe, 8th ed., which of the following lists is the correct sequence of stars in order of increasing temperature?
A. Sirius B, Deneb, Procyon B, the Sun B. Deneb, the Sun, Sirius B, Procyon B C. Sun, Procyon B, Deneb, Sirius B D. Procyon B, Sirius B, the Sun, Deneb |
C. Sun, Procyon B, Deneb, Sirius B
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Where on the Hertzsprung-Russell diagram do most local stars in our universe congregate?
A. white dwarf area, the “graveyard” of stars B. supergiant area, where the most massive stars spend a significant time C. giant area, where most stars spend the longest time of their lives D. main sequence, where stars are generating energy by fusion reactions |
D. main sequence, where stars are generating energy by fusion reactions
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Where on the Hertzsprung-Russell diagram do most local stars in our universe congregate?
A. white dwarf area, the “graveyard” of stars B. supergiant area, where the most massive stars spend a significant time C. giant area, where most stars spend the longest time of their lives D. main sequence, where stars are generating energy by fusion reactions |
D. main sequence, where stars are generating energy by fusion reactions
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A red supergiant star is found to have a surface temperature of 2500 K and a luminosity 100,000 times that of the Sun. Use the Hertzsprung-Russell diagram in Figure 11-8 of Comins and Kaufmann, Discovering the Universe, 8th ed.., to determine its approximate radius compared with that of the Sun.
A. about 10 times larger B. about 100 times larger C. about 1000 times larger D. almost the same |
C. about 1000 times larger
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A red supergiant star is found to have a surface temperature of 2500 K and a luminosity 100,000 times that of the Sun. Use the Hertzsprung-Russell diagram in Figure 11-8 of Comins and Kaufmann, Discovering the Universe, 8th ed.., to determine its approximate radius compared with that of the Sun.
A. about 10 times larger B. about 100 times larger C. about 1000 times larger D. almost the same |
C. about 1000 times larger
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The Sun's light is produced by three main sources: gravitational contraction, chemical burning, and nuclear fusion.
True False |
False The Sun's light is produced by nuclear fusion.
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The Sun's light is produced by three main sources: gravitational contraction, chemical burning, and nuclear fusion.
True False |
False The Sun's light is produced by nuclear fusion.
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There is no actual burning in nuclear burning.
True False |
True Hydrogen fusion occurring in the core can sustain the Sun for its entire 10 billion year lifetime.
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Nuclear fusion converts mass into energy. This means that by the time all of the hydrogen in the core of the Sun has been fused into helium, the Sun will be substantially less massive.
True False |
False Even if the Sun converted all of the hydrogen in its entire interior and atmosphere to helium, it would still lose only 0.7% of its mass.
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Which of the following equations correctly depicts the by-products of the proton-proton cycle?
4 protons → 4He + 2 positrons + 2 neutrinos 2 protons + 2 neutrons → 4He + 2 electrons + 1 neutrino 4 protons → 4He + 1 neutrino + 1 positron 2 protons + 2 electrons → 4He + 2 positrons |
4 protons → 4He + 2 positrons + 2 neutrinos
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Which of the following equations correctly depicts the by-products of the proton-proton cycle?
4 protons → 4He + 2 positrons + 2 neutrinos 2 protons + 2 neutrons → 4He + 2 electrons + 1 neutrino 4 protons → 4He + 1 neutrino + 1 positron 2 protons + 2 electrons → 4He + 2 positrons |
4 protons → 4He + 2 positrons + 2 neutrinos
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Some energy is generated in the proton-proton cycle as the result of the annihilation of which two particles?
electron & proton positron & electron proton & neutron positron & neutrino |
positron & electron The positron and electron are matter and antimatter; they convert entirely into energy when they collide.
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Einstein's equation, which determines the amount of energy created from a given amount of mass, is given by:
E = mc E = m2c E = mc2 E = m3c |
E = mc2
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Einstein's equation is energy = mass times the square of the speed of light.
8. Scientists realized that the Sun's energy cannot be due to gravitational contraction because the Sun would only last for: 600 years 100,000 years 20 million years 4 billion years |
20 million years
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What force keeps the protons in a nucleus bound together?
electromagnetic force gravitational force strong nuclear force weak nuclear force |
strong nuclear force
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What force keeps the protons in a nucleus bound together?
electromagnetic force gravitational force strong nuclear force weak nuclear force |
strong nuclear force
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Which force prevents protons from fusing in the Sun at temperatures below 10 million Kelvin?
electromagnetic force gravitational force strong nuclear force weak nuclear force |
electromagnetic force
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Which force prevents protons from fusing in the Sun at temperatures below 10 million Kelvin?
electromagnetic force gravitational force strong nuclear force weak nuclear force |
electromagnetic force
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If you move a star twice as far away from Earth compared to where it is now, it will appear half as bright.
True False |
FalseCorrect. According to the Inverse Square Law of Light, the brightness of a star depends on the inverse square of the distance. In this case the star would be ¼ as bright.
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The spectrum of a star is a direct indicator of the temperature of the star.
True False |
TrueThe temperature of a star directly controls which wavelengths will be absorbed by the gases in its stellar atmosphere.
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According to the H-R diagram, hotter stars are more luminous than cooler stars.
True False |
FalseCorrect. This is only true for stars on the Main Sequence. In general, the luminosity of a star depends not only on temperature, but also radius.
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Star A and star B appear to be the same apparent brightness, but through other means, you determine that Star A is four times as luminous as star B. How do their distances compare?
Star A is four times as far away as star B. Star A is twice as far away as star B. Star B is twice as far away as star A. Star B is four times as far away as star A. |
Star A is twice as far away as star B.Correct. According to the Inverse Square Law of Light, for a more luminous star to appear as bright as a less luminous star, it must be farther away. Also, since brightness is inversely related to the square of the distance, it is only twice as far away.
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A star has an apparent magnitude of +5 and an absolute magnitude of +2. Which of the following statements is true?
The star is closer than 10 pc. The star is as luminous as the Sun. The star is unobservable with the unaided eye. The star is farther than 10 pc. |
The star is farther than 10 pc.Correct. Since the distance modulus (apparent magnitude - absolute magnitude) is positive, the star is farther than 10 pc.
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A cool star, with a temperature of only 3000 K, will appear visibly as
red yellow white blue |
redCorrect. According to Wien's law, cool stars emit most of their visible light in the red portion of the spectrum.
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The hottest stars are spectral class
A B M O |
O. Correct. From hottest to coolest, stars are labeled O B A F G K M.
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If you know the absolute magnitude of a star, then you also know its
temperature. radius. luminosity. brightness. |
luminosityCorrect. The absolute magnitude of a star is analogous to its luminosity. Recall their positions on the axes of the H-R Diagram.
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Star C is as luminous as star D, but twice as hot. How does their sizes compare?
Star C is four times as big as star D. Star C is twice as big as star D. Star D is twice as big as star C. Star D is four times as big as star C. |
Star D is four times as big as star C.Correct. In order to be as luminous as star C, which is hotter, star D must be bigger. Since luminosity depends on the square of the radius and temperature to the fourth power, if star C is twice as hot, then star D must be four times as big (24 = 42).
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Where are the largest stars found on an H-R diagram?
In the upper-left hand corner. In the upper-right hand corner. In the lower-left hand corner. In the lower-right hand corner. |
In the upper-right hand corner.Correct. Radius increases from lower-left to upper-right, so the largest stars are found in the upper-right hand corner.
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In photographs, the Pleiades open star cluster is surrounded by a bluish haze (see Figure 12-2, Comins and Kaufmann, Discovering the Universe, 8th ed.). What causes this blue light?
A. starlight scattered from interstellar dust in the star cluster B. starlight scattered by the light-sensitive grains in the photographic plate when the picture was taken C. shock waves losing energy to interstellar gas in the star cluster, causing the atoms to emit light D. starlight absorbed and reemitted by interstellar gas in the star cluster |
A. starlight scattered from interstellar dust in the star cluster
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What major physical process is taking place inside stars that are on the main sequence in the Hertzsprung-Russell diagram?
A. Hydrogen is being converted to helium in their cores. B. Hydrogen is being converted to helium in a shell around the helium-rich core. C. Helium is being converted to carbon in their cores. D. The gas is contracting gravitationally without nuclear reactions taking place. |
A. Hydrogen is being converted to helium in their cores.
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The stars that last longest are the stars
A. with the largest luminosity and highest temperature since they take the longest to cool down to invisibility. B. with the largest mass, that is, the largest amount of fuel. C. with the smallest mass. D. of intermediate mass; small-mass stars have little fuel and burn out quickly, while very massive stars burn their fuel very rapidly. |
C. with the smallest mass.
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The total time the Sun will spend as a main-sequence star is
A. at least 200 billion years (2 × 1011) years. B. about 1 million years. C. about 4.5 million years. D. about 10 billion years (1010 years). |
D. about 10 billion years (1010 years).
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The total time the Sun will spend as a main-sequence star is
A. at least 200 billion years (2 × 1011) years. B. about 1 million years. C. about 4.5 million years. D. about 10 billion years (1010 years). |
D. about 10 billion years (1010 years).
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How large will the Sun be as a red giant?
A. about 1 AU radius (out to the Earth's orbit) B. about 1/10 AU radius (1/4 of Mercury's orbit) C. about 1.5 AU radius (out to Mars's orbit) D. about 1/2 AU radius (beyond Mercury's orbit) |
A. about 1 AU radius (out to the Earth's orbit)
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How large will the Sun be as a red giant?
A. about 1 AU radius (out to the Earth's orbit) B. about 1/10 AU radius (1/4 of Mercury's orbit) C. about 1.5 AU radius (out to Mars's orbit) D. about 1/2 AU radius (beyond Mercury's orbit) |
A. about 1 AU radius (out to the Earth's orbit)
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Nuclear fusion reactions that convert helium into carbon and oxygen in the central core of a star occur during which phase of a star's life?
A. in the red giant stage, before helium flash B. during and immediately after the (first) red giant or supergiant stage C. during the protostar stage D. after the main-sequence phase, before the star becomes a red giant |
B. during and immediately after the (first) red giant or supergiant stage
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Cepheid stars are
A. giant stars that pulsate in brightness, size, and temperature. B. white dwarf stars late in their evolutionary life. C. members of binary systems in which one star periodically eclipses the other. D. stars at an early stage in stellar evolution, pre–main-sequence. |
A. giant stars that pulsate in brightness, size, and temperature.
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Cepheid stars are
A. giant stars that pulsate in brightness, size, and temperature. B. white dwarf stars late in their evolutionary life. C. members of binary systems in which one star periodically eclipses the other. D. stars at an early stage in stellar evolution, pre–main-sequence. |
A. giant stars that pulsate in brightness, size, and temperature.
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How do astronomers know that globular clusters are very old?
A. Globular clusters do not contain any red giant stars. B. There are no main-sequence stars in globular clusters. C. The stars in a globular cluster have a high abundance of heavy elements. D. There are no massive main-sequence stars in globular clusters. |
D. There are no massive main-sequence stars in globular clusters.
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A planetary nebula is a(n)
A. contracting spherical cloud of gas surrounding a newly formed star in which planets are forming. B. expanding gas shell surrounding a hot, burned-out stellar core. C. disk-shaped nebula of dust and gas around a relatively young star, from which planets will eventually form. D. nebula caused by the supernova explosion of a massive star. |
B. expanding gas shell surrounding a hot, burned-out stellar core.
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How does a white dwarf generate its energy?
A. It no longer generates energy but is slowly cooling as it radiates away its heat. B. Nuclear fusion of hydrogen into helium is producing energy in its core. C. Nuclear fission of heavy elements in the central core is releasing energy. D. Gravitational potential energy is released as the star slowly contracts. |
A. It no longer generates energy but is slowly cooling as it radiates away its heat.
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How does a white dwarf generate its energy?
A. It no longer generates energy but is slowly cooling as it radiates away its heat. B. Nuclear fusion of hydrogen into helium is producing energy in its core. C. Nuclear fission of heavy elements in the central core is releasing energy. D. Gravitational potential energy is released as the star slowly contracts. |
A. It no longer generates energy but is slowly cooling as it radiates away its heat.
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For a massive star, core fusion of each successive element lasts longer than the previous one.
True False |
FalseCorrect. Each successive element is burned for a shorter time than its predecessor.
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Nothing can stop the collapse of a high-mass (> 4 M) star once its core is composed of iron.
True False |
False Correct. Degenerate neutron pressure can stop the collapse of high-mass stars whose cores are less than 2-3 M. It is the mass of the core that remains after the supernova, not the original mass of the star, which determines whether the star ends as a neutron star or black hole.
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The elements produced by post-main-sequence fusion in the core and shells of a massive star enrich the interstellar medium when they are later expelled by the supernova explosion.
True False |
FalseCorrect. The elements produced by fusion in massive star are destroyed by photodisintegration during the collapse. Materials created by the shock wave during the explosion enrich the interstellar medium.
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Type II supernovae can be identified by their light curves.
True False |
TrueCorrect. Type II supernovae produce roughly the same radioactive elements and therefore have very similar light curves.
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Type II supernovae can be identified by their light curves.
True False |
TrueCorrect. Type II supernovae produce roughly the same radioactive elements and therefore have very similar light curves.
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Which of the following is a way in which low-mass and high-mass stars are similar?
Number of fusion cycles (shells) the star will have in its lifetime. Length of main-sequence lifetime. Red giant stage after leaving the main sequence. Final product of star death. |
Red giant stage after leaving the main sequence.
Correct. All stars fuse helium in their core during their post-main-sequence lifetimes after hydrogen fusion ends. Correct. All stars fuse helium in their core during their post-main-sequence lifetimes after hydrogen fusion ends. |
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The minimum initial mass for stars that die the most violent deaths is:
1 M 4 M 8 M 10 M |
8 M
Correct. Stars with masses greater than 8 M end their lives as supernovae. |
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Which of the following observations have NOT helped to confirm supernova theory?
Neutrinos Spectra Light curves Neutron degeneracy pressure |
Neutron degeneracy pressure
Correct. Neutron degeneracy pressure has been calculated theoretically, but not measured experimentally. |
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The collapse of the core of a massive star takes roughly
one second one year one thousand years one million years |
one second
Correct. After millions of years of evolution, the core of the star is destroyed in roughly one second. |
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Iron fusion does NOT occur in the core of a massive star because:
The star explodes as a supernova before iron fusion has a chance to begin. The core of even a very massive star cannot reach the temperatures and pressures needed to fuse iron. There is simply not enough iron in the core for fusion to take place. Fusion of iron consumes energy instead of producing energy. |
Fusion of iron consumes energy instead of producing energy.
Correct. Iron fusion is not an energy source and would not help support the core against collapse. |
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The spectra of Type II supernovae show strong evidence of
Hydrogen Helium Carbon Iron |
Hydrogen
Correct. Fusion occurs only in the core (and the surrounding shell layers) of a star; its outer envelope is still predominately hydrogen. This results in strong hydrogen lines in the spectra of Type II supernovae. |
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When hydrogen fusion stops, the core cools because it has no energy source.
True False |
FalseCorrect. Due to its contraction, the core actually heats up when hydrogen fusion ends.
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Hydrogen shell fusion actually increases the rate at which the core contracts.
True False |
True
Correct. Hydrogen shell fusion causes helium to "rain" down on the contracting core, increasing its mass and thus speeding its contraction. |
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When it becomes a red giant, our Sun will be about twice as large as it is now!
True False |
FalseCorrect. Our Sun will swell to about 100 times its current size, with a diameter of approximately 1 AU.
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The horizontal branch lifetime of a star is roughly equal to its main-sequence lifetime.
True False |
FalseCorrect. The horizontal branch lifetime is much less than the main-sequence lifetime for all stars regardless of mass.
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In a low mass red giant star, degeneracy occurs when ______ are pushed together as close as they can be according to the laws of quantum physics.
protons neutrons electrons photons |
electrons
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A star in the horizontal branch phase is _______ than it was on the main sequence.
hotter, bigger, dimmer cooler, smaller, dimmer cooler, bigger, brighter hotter, smaller, brighter |
cooler, bigger, brighter
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A star in the horizontal branch phase is _______ than it was on the main sequence.
hotter, bigger, dimmer cooler, smaller, dimmer cooler, bigger, brighter hotter, smaller, brighter |
cooler, bigger, brighter
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Stars less than ___ M never become giants.
0.4 4 1.4 2.4 |
0.4
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Red giant stars lose large amounts of mass due to their:
strong winds. weak magnetic fields weak surface gravities cool surface temperatures |
weak surface gravities
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Red giant stars lose large amounts of mass due to their:
strong winds. weak magnetic fields weak surface gravities cool surface temperatures |
weak surface gravities
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Once core hydrogen fusion ceases, the star will not regain equilibrium until:
hydrogen shell fusion begins. helium core fusion begins. helium shell fusion begins. the star never achieves equilibrium again. |
helium core fusion begins.
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Once core hydrogen fusion ceases, the star will not regain equilibrium until:
hydrogen shell fusion begins. helium core fusion begins. helium shell fusion begins. the star never achieves equilibrium again. |
helium core fusion begins.
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The helium flash occurs due to:
high temperatures in the core. lack of equilibrium in the core. degeneracy in the core. helium burning throughout the core. |
The helium flash occurs due to:
high temperatures in the core. lack of equilibrium in the core. degeneracy in the core. helium burning throughout the core. |
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If a star has more than 3 solar masses worth of material, it will definitely end its life as a black hole. True False
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FalseCorrect. The end state of a star depends on the amount of mass that remains after it sheds its outer layers, not on its total mass. If the remnant mass is more than 3 solar masses, then it will collapse into a black hole.
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According to Einstein's Theory of General Relativity, gravity can alter the path of photons, as well as matter.
True False |
TrueCorrect. According to Einstein's theory, gravity is just a curvature of space due to the presence of a massive object. It affects everything moving through space, including photons.
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The theory that mass curves space has no supporting observations.
True False |
False. Correct. Among other observational evidence, astronomers have observed light from a star during a solar eclipse which was supposed to lie directly behind the Sun. The star was observable because its light was curved around the Sun, hitting the Earth.
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A black hole has three physical properties.
True False |
True Correct. Mass, electric charge, and angular momentum.
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In a black hole, the inward force of gravity is balanced by which outward force?
Radiation pressure. Electron degeneracy pressure. Neutron degeneracy pressure. In a black hole, there is no other force strong enough to balance the inward force of gravity. |
In a black hole, there is no other force strong enough to balance the inward force of gravity.
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Black holes are unique in that they have an infinite
mass density volume charge |
density
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Black holes are unique in that they have an infinite
mass density volume charge |
density
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At what speed would an object located at a distance of 4 RSch (four times the Schwarzschild radius) from a black hole need to travel in order to escape its gravitational pull?
0.25c 0.5c 0.707c c |
0.5c Correct. According to the formula, escape speed is inversely proportional to the square root of the distance. At the Schwarzschild radius, the escape speed is equal to c (the speed of light). Four times farther away, the escape speed is (1/√4 = ½) as large, or 0.5c.
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How does the Schwarzschild radius of a black hole depend on its mass?
The greater the mass, the bigger the Schwarzschild radius. The greater the mass, the smaller the Schwarzschild radius. The Schwarzschild radius does not depend on the mass of a black hole. |
The greater the mass, the bigger the Schwarzschild radius.
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How does the Schwarzschild radius of a black hole depend on its mass?
The greater the mass, the bigger the Schwarzschild radius. The greater the mass, the smaller the Schwarzschild radius. The Schwarzschild radius does not depend on the mass of a black hole. |
The greater the mass, the bigger the Schwarzschild radius.
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The event horizon of a black hole is defined as
The physical edge of the central mass of the black hole. The distance from the black hole at which light can just barely escape from its gravitational pull. The distance from the black hole at which an Earth-like planet would not get sucked in. The distance from the black hole at which it no longer exerts any gravitational pull on any object. |
The distance from the black hole at which light can just barely escape from its gravitational pull.
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If the Sun were replaced by a 1 solar mass black hole, what would happen to its gravitational influence on the Earth?
It would increase. It would decrease. It would stay the same. There is not enough information to determine this. |
It would stay the same.
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The escape velocity for material inside a black hole is
A. zero. B. infinite. C. greater than the speed of light. D. twice that from a neutron star. |
C. greater than the speed of light.
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What is the likely final fate of a star of 15 solar masses when it is on the main sequence?
A. The star will collapse and become a black hole. B. The star will condense to the point where it is composed completely of neutrons, the degeneracy of which will prevent further shrinkage. C. The degeneracy of the electrons in the star will prevent collapse below the diameter of a white dwarf. D. The star will immediately split in two and become a binary star system. |
B. The star will condense to the point where it is composed completely of neutrons, the degeneracy of which will prevent further shrinkage.
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In a binary star system, one component is found to have about 3 solar masses, the other about 7 solar masses. The 3-solar-mass star is visible from Earth, but the 7-solar-mass star is not. Theoretical considerations tell us that the 7-solar-mass star must be a
A. neutron star. B. cool planetary object. C. white dwarf. D. black hole. |
D. black hole.
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What would happen to the gravitational force on Earth if the Sun were to be replaced by a 1-solar-mass black hole?
A. The gravitational force on Earth would become extremely high, sufficient to pull Earth into the black hole. B. The gravitational force on Earth would double in strength. C. The gravitational force on Earth would remain as it is now. D. The gravitational force on Earth would be much less because the gravitational field of a black hole exists only very close to it. |
C. The gravitational force on Earth would remain as it is now.
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In the context of black holes, what is a wormhole?
A. “tunnel” of undistorted space through an event horizon allowing objects to enter and leave a black hole without being torn apart B. direct connection from any black hole to another part of spacetime C. small, black hole through a solid object such as a planet D. direct connection from a rotating black hole to another part of spacetime |
D. direct connection from a rotating black hole to another part of spacetime
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Supposedly nothing can escape from a black hole, yet astronomers are locating black hole candidates by the X rays they emit. How can X rays be coming from a black hole?
A. The X rays come from a highly compressed region in an accretion disk outside the event horizon of the black hole. B. X rays are not light or matter and can therefore escape from inside the black hole. C. If the black hole is rotating, it modifies spacetime around it so much that particles and X rays are created in the vacuum just outside the event horizon. D. The X rays are produced by vibrations of the black hole itself and therefore do not come from inside the black hole. |
A. The X rays come from a highly compressed region in an accretion disk outside the event horizon of the black hole.
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The Milky Way Galaxy
A. is one of many billions of galaxies in the universe. B. is unique in the universe in showing definite spiral structure. C. contains the whole universe; everything observable is within its volume. D. is one of only a few spiral galaxies; most other galaxies in the universe are amorphous collections of stars shaped like ellipsoids. |
A. is one of many billions of galaxies in the universe.
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Variable stars such as Cepheid variables are used in what important measurement in astronomy?
A. measurement of the distances to stars B. measurement of the rotation speeds of galaxies C. measurement of the surface temperatures of stars D. keeping of accurate time |
A. measurement of the distances to stars
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Variable stars such as Cepheid variables are used in what important measurement in astronomy?
A. measurement of the distances to stars B. measurement of the rotation speeds of galaxies C. measurement of the surface temperatures of stars D. keeping of accurate time |
A. measurement of the distances to stars
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The method Hubble used to determine the distance to the Andromeda Galaxy (M31), thereby establishing the concept of separate and individual galaxies throughout the universe, was the
A. observation of Cepheid variable stars. B. measurement of the redshift of the whole galaxy. C. measurement of stellar parallax, or apparent motion, of stars because of Earth's orbital motion. D. observation of the brightnesses of novae. |
A. observation of Cepheid variable stars.
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Where is the Sun located in the Milky Way Galaxy? (That is, what is the address of the Sun in the universe?) (See Figure 15-9 of Comins and Kaufmann, Discovering the Universe, 8th ed.)
A. in the Centaurus arm, between the galactic center and the Orion arm B. in the Sagittarius arm, between the Centaurus and Orion arms C. in the Perseus arm, between the Orion and Cygnus arms D. in or close to the Orion arm, between the Sagittarius and Perseus arms. |
D. in or close to the Orion arm, between the Sagittarius and Perseus arms.
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What evidence now exists for a supermassive black hole at the center of the Milky Way Galaxy?
A. very bright X-ray emissions from the galactic center B. observations of intense inflow of matter toward the center of the Galaxy as seen by light, Doppler-shifted toward the red, emitted by this matter C. very rapid motion of matter close to the nucleus of the Galaxy, requiring a very massive body to hold it in orbit D. very dark void in an otherwise bright region of space near the galactic center, indicating the presence of a black hole |
C. very rapid motion of matter close to the nucleus of the Galaxy, requiring a very massive body to hold it in orbit
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The presence of a very large amount of unseen matter (“dark matter”)in the halo of the Milky Way Galaxy is deduced from
A. the rotation curve of the Galaxy, in which orbital speeds of stars appear to obey Kepler's law. B. the rotation curve of the Galaxy, in which orbital speeds of stars in the outer regions of the Galaxy are significantly higher than is predicted by Kepler's law in which the value for the observed mass in the Galaxy is used. C. the unexpected absence of luminous matter (stars, and so on) beyond a certain distance from the galactic center. D. the high amount of interstellar absorption in certain directions. |
B. the rotation curve of the Galaxy, in which orbital speeds of stars in the outer regions of the Galaxy are significantly higher than is predicted by Kepler's law in which the value for the observed mass in the Galaxy is used.
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The presence of a very large amount of unseen matter (“dark matter”)in the halo of the Milky Way Galaxy is deduced from
A. the rotation curve of the Galaxy, in which orbital speeds of stars appear to obey Kepler's law. B. the rotation curve of the Galaxy, in which orbital speeds of stars in the outer regions of the Galaxy are significantly higher than is predicted by Kepler's law in which the value for the observed mass in the Galaxy is used. C. the unexpected absence of luminous matter (stars, and so on) beyond a certain distance from the galactic center. D. the high amount of interstellar absorption in certain directions. |
B. the rotation curve of the Galaxy, in which orbital speeds of stars in the outer regions of the Galaxy are significantly higher than is predicted by Kepler's law in which the value for the observed mass in the Galaxy is used.
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How are galaxies spread throughout the universe?
A. Galaxies are densest near the Milky Way Galaxy and become less and less numerous the farther we look out into the universe. B. Galaxies are grouped in clusters that are spread more or less evenly throughout the universe. C. Galaxies are spread more or less evenly throughout the universe. D. Clusters of galaxies exist that are themselves often clustered into superclusters. Clusters and superclusters appear to be distributed on surfaces surrounding empty regions of space. |
D. Clusters of galaxies exist that are themselves often clustered into superclusters. Clusters and superclusters appear to be distributed on surfaces surrounding empty regions of space.
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What is the Local Group?
A. stars that occupy the same spiral arm as the Sun B. cluster of about 40 galaxies of which the Milky Way is one C. group of galaxies clustered around the Andromeda Galaxy M31, apparently gravitationally bound to it but separate from the Milky Way D. group of about 100 stars within 20 ly of the Sun that appear to have been formed at about the same time from similar material |
B. cluster of about 40 galaxies of which the Milky Way is one
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What is the Local Group?
A. stars that occupy the same spiral arm as the Sun B. cluster of about 40 galaxies of which the Milky Way is one C. group of galaxies clustered around the Andromeda Galaxy M31, apparently gravitationally bound to it but separate from the Milky Way D. group of about 100 stars within 20 ly of the Sun that appear to have been formed at about the same time from similar material |
B. cluster of about 40 galaxies of which the Milky Way is one
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What do we know about the geometry of the “dark matter” distribution in the vicinity of the Milky Way Galaxy?
A. The dark matter appears to be a lens-shaped disk like the Galaxy's disk of visible stars, only larger. B. The dark matter appears to be a spherical halo. C. Dark matter, including that near the Milky Way Galaxy, appears to be part of a uniform density distribution that fills all space. D. The geometry of the dark matter distribution, like its constituents, is totally unknown at the present time. |
B. The dark matter appears to be a spherical halo.
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What do we know about the geometry of the “dark matter” distribution in the vicinity of the Milky Way Galaxy?
A. The dark matter appears to be a lens-shaped disk like the Galaxy's disk of visible stars, only larger. B. The dark matter appears to be a spherical halo. C. Dark matter, including that near the Milky Way Galaxy, appears to be part of a uniform density distribution that fills all space. D. The geometry of the dark matter distribution, like its constituents, is totally unknown at the present time. |
B. The dark matter appears to be a spherical halo.
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The energy output per second of a typical quasar is equal to that emitted by the Sun in
A. 1 year. B. its whole lifetime. C. 200 years. D. 1 million years. |
C. 200 years.
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What is the most outstanding feature of a quasar compared with other objects in deep space?
A. small size B. great distance from Earth C. short lifetime D. prodigious output of energy |
D. prodigious output of energy
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Quasars all appear to be
A. extremely massive objects in the Milky Way Galaxy, their spectra showing very high gravitational redshift. B. moving away from us at very high speeds, up to about 90% of the speed of light. C. moving across our line of sight at very high speeds, as seen in time-lapse photographs. D. moving toward us at high speeds, as high as 90% of the speed of light. |
B. moving away from us at very high speeds, up to about 90% of the speed of light.
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Quasars all appear to be
A. extremely massive objects in the Milky Way Galaxy, their spectra showing very high gravitational redshift. B. moving away from us at very high speeds, up to about 90% of the speed of light. C. moving across our line of sight at very high speeds, as seen in time-lapse photographs. D. moving toward us at high speeds, as high as 90% of the speed of light. |
B. moving away from us at very high speeds, up to about 90% of the speed of light.
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The surprising observational fact about quasars is that they appear to
A. produce the energy output of greater than 100 galaxies in a volume similar to that of our planetary system. B. be the largest known structures in the universe, although they produce only modest amounts of energy. C. be associated with ancient supernova explosions. D. be moving rapidly toward us while emitting large amounts of energy. |
A. produce the energy output of greater than 100 galaxies in a volume similar to that of our planetary system.
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The surprising observational fact about quasars is that they appear to
A. produce the energy output of greater than 100 galaxies in a volume similar to that of our planetary system. B. be the largest known structures in the universe, although they produce only modest amounts of energy. C. be associated with ancient supernova explosions. D. be moving rapidly toward us while emitting large amounts of energy. |
A. produce the energy output of greater than 100 galaxies in a volume similar to that of our planetary system.
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Where do we find supermassive black holes?
A. in the centers of giant elliptical galaxies B. in the centers of active galaxies C. in the centers of both active and normal galaxies, but only those at relatively high redshift values, indicating that they existed in the distant past D. in the centers of both active and normal galaxies, both nearby and far away |
D. in the centers of both active and normal galaxies, both nearby and far away
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Where do we find supermassive black holes?
A. in the centers of giant elliptical galaxies B. in the centers of active galaxies C. in the centers of both active and normal galaxies, but only those at relatively high redshift values, indicating that they existed in the distant past D. in the centers of both active and normal galaxies, both nearby and far away |
D. in the centers of both active and normal galaxies, both nearby and far away
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Why is the universe expanding?
A. The energy from all the stars is heating the universe, making it expand like a gas that is heated. B. Spacetime itself is expanding, carrying the galaxies (or superclusters of galaxies) with it. C. The universe is not expanding—it is we who are getting smaller, making the universe seem bigger and bigger. D. An infinitely dense clump of matter exploded, sending the galaxies (or superclusters of galaxies) hurtling out through space. |
B. Spacetime itself is expanding, carrying the galaxies (or superclusters of galaxies) with it.
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What is the “cosmological redshift”?
A. stretching of the wavelengths of photons as they travel through expanding space B. stretching of the wavelengths of photons by the Doppler shift because they are emitted by galaxies that are moving away from us C. loss of energy from photons interacting with virtual particles in the vacuum, resulting in the wavelength of the photons gradually increasing as they travel toward us through space D. stretching of the wavelengths of photons as they pass through absorbing matter in galaxies between us and the emitting galaxy |
A. stretching of the wavelengths of photons as they travel through expanding space
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What is the “cosmological redshift”?
A. stretching of the wavelengths of photons as they travel through expanding space B. stretching of the wavelengths of photons by the Doppler shift because they are emitted by galaxies that are moving away from us C. loss of energy from photons interacting with virtual particles in the vacuum, resulting in the wavelength of the photons gradually increasing as they travel toward us through space D. stretching of the wavelengths of photons as they pass through absorbing matter in galaxies between us and the emitting galaxy |
A. stretching of the wavelengths of photons as they travel through expanding space
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According to Hubble's law, how old is the universe (H0 = Hubble's constant)?
A. v/H0 (where v = recession velocity in km/s) B. r/H0 (where r = distance in Mpc) C. H0 D. 1/H0 |
D. 1/H0
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Calculate the age of the universe if Hubble's constant, H0, is 60 km/s/Mpc (see Astronomer's Toolbox 18-1, Comins and Kaufmann, Discovering the Universe, 8th ed.).
A. 15.0 billion years B. 16.6 billion years C. 60 billion years D. 11.1 billion years |
B. 16.6 billion years
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Calculate the age of the universe if Hubble's constant, H0, is 60 km/s/Mpc (see Astronomer's Toolbox 18-1, Comins and Kaufmann, Discovering the Universe, 8th ed.).
A. 15.0 billion years B. 16.6 billion years C. 60 billion years D. 11.1 billion years |
B. 16.6 billion years
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Where is the Earth?
A. at the exact center of an expanding universe, as shown by the universal expansion away from Earth in all directions B. near the edge of an expanding universe, as shown by the microwave radiation coming to Earth from the edge C. near but probably not right at the center of the universe, as shown by the fact that the edge is so far away from Earth D. somewhere in an expanding universe but not in any special part of it |
D. somewhere in an expanding universe but not in any special part of it
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Where is the Earth?
A. at the exact center of an expanding universe, as shown by the universal expansion away from Earth in all directions B. near the edge of an expanding universe, as shown by the microwave radiation coming to Earth from the edge C. near but probably not right at the center of the universe, as shown by the fact that the edge is so far away from Earth D. somewhere in an expanding universe but not in any special part of it |
D. somewhere in an expanding universe but not in any special part of it
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Good evidence for an original Big Bang that “created” our universe comes from
A. the rapid motions of some nearby stars, such as Barnard's star. B. a background “glow” of microwaves, with blackbody temperature of about 3 K. C. the measurement of the rotation of the Milky Way Galaxy. D. the amount of gas and dust in the solar neighborhood. |
B. a background “glow” of microwaves, with blackbody temperature of about 3 K.
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If the geometry of space is spherical, what is the future of the universe?
A. The future of the universe is not related to the geometry of space. B. The universe will expand forever, not stopping even when infinite time has elapsed. C. The universe will hardly expand forever; if it has any more matter in it than it does, it will eventually stop expanding and start to collapse. D. The universe will expand to a maximum size and then collapse into a Big Crunch. |
D. The universe will expand to a maximum size and then collapse into a Big Crunch.
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If the geometry of space is spherical, what is the future of the universe?
A. The future of the universe is not related to the geometry of space. B. The universe will expand forever, not stopping even when infinite time has elapsed. C. The universe will hardly expand forever; if it has any more matter in it than it does, it will eventually stop expanding and start to collapse. D. The universe will expand to a maximum size and then collapse into a Big Crunch. |
D. The universe will expand to a maximum size and then collapse into a Big Crunch.
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Which element(s) was(were) created during the Big Bang?
A. hydrogen and helium B. hydrogen, helium, lithium, and beryllium C. hydrogen D. hydrogen, helium, and lithium |
D. hydrogen, helium, and lithium
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Which element(s) was(were) created during the Big Bang?
A. hydrogen and helium B. hydrogen, helium, lithium, and beryllium C. hydrogen D. hydrogen, helium, and lithium |
D. hydrogen, helium, and lithium
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Which parameter of the present universe is considered to be critical in determining the ultimate fate of the universe?
A. amount of mass in black holes in the universe B. number of neutrinos in the universe C. amount of matter and energy in the universe D. number of photons of radiation in the universe |
C. amount of matter and energy in the universe
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Which parameter of the present universe is considered to be critical in determining the ultimate fate of the universe?
A. amount of mass in black holes in the universe B. number of neutrinos in the universe C. amount of matter and energy in the universe D. number of photons of radiation in the universe |
C. amount of matter and energy in the universe
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The Drake equation attempts to predict the
A. number of inhabitable planets around stars in the Milky Way Galaxy. B. number of intelligent civilizations that exist in the whole universe. C. probability of primitive life existing elsewhere in the Milky Way Galaxy. D. number of technically advanced civilizations in the Milky Way Galaxy. |
D. number of technically advanced civilizations in the Milky Way Galaxy.
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The Drake equation attempts to predict the
A. number of inhabitable planets around stars in the Milky Way Galaxy. B. number of intelligent civilizations that exist in the whole universe. C. probability of primitive life existing elsewhere in the Milky Way Galaxy. D. number of technically advanced civilizations in the Milky Way Galaxy. |
D. number of technically advanced civilizations in the Milky Way Galaxy.
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