Questão 1
Questão
What advantage do you gain by having two eyes that are separated on your face, rather than being very close together?
Responda
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Better collecting area, which allows you to see dimmer objects
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Double vision, which allows you to see multiple objects at once
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Color vision, which allows you to determine temperatures
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Stereoscopic vision, which allows you to determine distances
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Better magnification, which allows you to see smaller objects
Questão 2
Questão
To measure the parallax of the most distant stars measurable, we would make two measurements of the star's position on the sky separated by:
Responda
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6 hours
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12 hours
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24 hours
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6 months
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2 months
Questão 3
Questão
Stars A and B appear equally bright, but star A is twice as far away from us as star B. Which of the following is true?
Responda
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Star A is twice as luminous as star B
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Star A is four times as luminous as star B
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Star B is four times as luminous as star B
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Star B is twice as luminous as star A
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Star A and star B have the same luminosity because they have the same brightness
Questão 4
Questão
Which sequence correctly lists the spectral classes of stars in order from hottest to coolest?
Responda
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ABFGKMO
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OABGFMK
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EIEIO
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OBAFGKM
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MKGFABO
Questão 5
Questão
The faster-moving star in a binary is:
Questão 6
Questão
On a typical H-R diagram, where are the stars with the largest radii located?
Questão 7
Questão
The one property of a main-sequence star that determines all its other properties is its:
Responda
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Luminosity
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Mass
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Temperature
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Spectral Type
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Brightness
Questão 8
Questão
Hydrostatic equilibrium is a balance between:
Responda
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Heat and centrifugal force
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Core temperature and surface temperature
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Pressure and gravity
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Radiation and heat
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Centrifugal force and gravity
Questão 9
Questão
The majority of the Sun's energy come from:
Responda
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Gravitational contraction
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Nuclear fission of uranium
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Hydrogen fusion
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Helium burning
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Burning material as in a fire
Questão 10
Questão
If the core of the Sun were hotter than it is now, how would the Sun's energy production change?
Responda
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It would produce less energy per second then it does now
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It would produce more energy per second than it does now
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Its energy production would vary more than it does now
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Its energy production would be more stable than it is now
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The Sun's energy production would not change
Questão 11
Questão
What do astronomers mean when they say that the Sun makes energy by hydrogen burning?
Responda
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The Sun is combusting hydrogen in a fire and releasing energy
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The Sun is fusing hydrogen into uranium and releasing energy
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The Sun is made of mostly hydrogen at very high temperature
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The Sun is fusing hydrogen into helium and releasing energy
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The Sun is accumulating hydrogen from the solar wind and releasing energy
Questão 12
Questão
Which of these can travel directly from the center of the Sun to Earth in about 8 minutes?
Responda
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Photons
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Electrons
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Protons
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Neutons
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Neutinos
Questão 13
Questão
The magnetic field of the Sun is continuously produced and deformed by:
Responda
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Its differential rotation
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The solar wind
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Changes in the rate of nuclear fusion in the core
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Liquid conducting layer in the interior
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This is a trick question, the solar magnetic field is primordial
Questão 14
Questão
If you could watch stars forming out of a gas cloud, which stars would form first?
Questão 15
Questão
Warm ionized gas in the interstellar medium appear _____ when imaged in the optical region of the electromagnetic spectrum.
Responda
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Red
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Yellow
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White
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Blue
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Dark
Questão 16
Questão
21-cm radiation is important because:
Responda
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It allows us to study the deep interiors of stars
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It allows us to image magnetic fields directly
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It allows us to study neutral hydrogen in the interstellar medium
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It is produced by every object in the universe
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It is the longest wavelength of light that can naturally be produced
Questão 17
Questão
An accretion disk forms around a collapsing protostar because infalling material must conserve:
Responda
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Energy
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Centrifugal force
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Gravity
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Velocity
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Angular Momentum
Questão 18
Questão
The source of energy for a contracting protostar comes from:
Questão 19
Questão
Of the following processes at work in molecular clouds, which is the one that inevitably dominates the clouds's evolution?
Questão 20
Questão
What critical event transforms a protostar into a normal main-sequence star?
Responda
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Planets in the accretion disk
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The star grows suddenly larger in radius
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Triple alpha reactions begin in the core
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Nuclear fusion begins in the core
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Convection begins throughout the star's interior
Questão 21
Questão
A nova is the result of which explosive situation?
Responda
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Mass transfer onto a white dwarf
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Helium burning in a degenerate stellar core
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A white dwarf which exceeds the Chandrasekhar limit
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The collision of members of a binary system
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Runaway nuclear reactions in the core
Questão 22
Questão
The principal means by which high-mass stars generate energy on the main sequence is called:
Questão 23
Questão
Massive stars synthesize chemical elements going from helium up to iron:
Responda
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Throughout the interior
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Primarily at the surface
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Only in the core of the star
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Along the equator of the star
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In a deep convection zone in the interior of the star
Questão 24
Questão
What causes massive stars to expel their outer layers?
Responda
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Radiation pressure
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High magnetic fields
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Rapid rotation
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Carbon fusion
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Emission of neutrinos
Questão 25
Questão
During the main-sequence evolution of a massive star, increasingly heavier elements are fused in the core, giving the core support for:
Responda
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Longer and longer times
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Shorter and shorter times
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An approximately equal amount of time
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Approximately 10,000 years
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Only a few days
Questão 26
Questão
The Crab Nebula is an important test of our ideas about supernova explosions because:
Responda
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People saw the supernova and later astronomers found a pulsar inside the nebula
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The system contains X-Ray binary
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The nebula is expanding slowly, as expected from mass loss rates in massive stars
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Crabs must have evolved before humans
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Astronomers observed the merger of the two stars
Questão 27
Questão
Which of these begins first in the core of a massive star?
Questão 28
Questão
Where did all heavy elements in the Sun come from?
Responda
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Previous generation of stars seeded the interstellar medium out of the Sun formed
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Nearby supernova explosions directly contaminated the Sun's surface
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Nucleosynthesis within the Sun generated all the elements we see in the solar spectrum
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The Sun gobbled up some planets during the early days of our Solar System
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The solar wind carries away hydrogen and helium, leaving behind the heavy elements
Questão 29
Questão
Iron has 26 protons in its nucleus, and gold has 79 protons. Where did all the gold on the Earth come from?
Responda
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Nucleosynthesis on the surfaces of neutron stars
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Nucleosynthesis that took place in supernova explosions
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Nucleosynthesis in the cores of low-mass stars
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Nucleosynthesis in the cores of massive stars
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Nucleosynthesis in red giant and horizontal-branch stars
Questão 30
Questão
According to Einstein's relativity, which two quantities are different manifestations of the same thing?
Responda
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Mass and gravity
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Light and energy
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Energy and mass
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Temperature and energy
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Distance and time