PHY 109: Astronomy and Cosmology The Solar System
Fall 2003 Prof. Cote's Website • Astronomy at Rutgers • Department of Physics & Astronomy • Rutgers University
Last updated November 8, 2003
Second Midterm: Solutions
Note that the order of the questions given here may differ from that on your exam.
Mountaintops are good locations for optical and infrared telescopes because they
are closer to astronomical objects. have cold weather which improves the performance of the instruments. are above the ozone layer, which absorbs optical and infrared light. have gentle winds, which reduces the atmospheric turbulence. are located above much of the atmosphere.
This type of telescope uses a flat secondary mirror to form an image.
Newtonian. Cassegrain. Coude. Maksutov. Refracting.
Two optical telescopes are in orbit above the Earth. The first telescope has a primary mirror of diameter 2 meters; the primary mirror of the second telescope has a diameter of 6 meters. How does the angular resolution of the first telescope compare to that of the second?
Nine times worse. Nine times better. Three times worse. Two times worse. Four times better.
A single radio telescope has poorer angular resolution than a typical optical telescope because
radio telescopes have much smaller diameters than optical telescopes. radio telescopes work at much longer wavelengths than optical telescopes. turbulence in the Earth's atmosphere affects radio waves much more than visible light. all celestial radio sources are extremely weak. the atmosphere is opaque to most radio waves.
In which of the following lists are light detectors ranked in order of increasing efficiency?
The human eye, CCDs, photo-emissive detectors, photographic plates. Photographic plates, CCDs, the human eye, photo-emissive detectors. The human eye, photographic plates, CCDs, photo-emissive detectors. CCDs, photo-emissive detectors, the human eye, photographic plates. The human eye, photographic plates, photo-emissive detectors, CCDs.
Which of the following is not a reason why all large telescopes are reflectors rather than refractors?
Large lenses are very expensive to build. The resolution of a lens is limited by diffraction, while the resolution of a mirror is not. Lenses suffer from chromatic aberration and mirrors do not. Large lenses are much more difficult to support than large mirrors. Lenses must have two high quality surfaces and no internal imperfections, mirrors need only one high quality surface and are relatively unaffected by internal imperfections.
Which space telescope, launched by NASA in 1999, has given us superb X-ray images of pulsars, neutron stars and galaxy clusters?
Hubble. Chandra. XMM. Arecibo. Hipparcos.
On the Earth, subduction zones are regions where:
One plate slides underneath another, returning older crust to the mantle. Hot mantle rises upward, creating volcanic island chains. Hot mantle rises upward and spreads sideways, pushing plates apart. Two plates slip sideways relative to one another. The cooling and shrinking of the lithosphere produces long, steep cliffs.
Which of the following gases absorbs ultraviolet light best?
Carbon dioxide. Oxygen. Nitrogen. This is a trick question. None of these gases absorb ultraviolet light. Ozone.
Which of the following is {\it not} a characteristic of Jovian planets?
They are closer to the Sun than the Terrestrial planets. They rotate more rapidly than the Terrestrial planets. They are more massive than the Terrestrial planets. They have stronger magnetic fields than the Terrestrial planets. They have many more moons than the Terrestrial planets.
Two spherical planets have the same mass. The radius of planet A is twice that of planet B. How does the density of planet A compare to that of planet B?
One eighth that of planet B. The same as planet B. One half that of planet B. Two times that of planet B. Eight times that of planet B.
How was Galileo able to conclude that the Sun is not a solid body?
By observing the phases of Venus. By measuring the seasonal variations in auroral intensity. By tracking the motions of sunspots. By measuring variations in the heights of spring tides. By measuring variations in the solar neutrino flux.
Which of the following planets could never transit the Sun as seen from Jupiter?
Mercury. Venus. Earth. Mars. Saturn.
The 11 year solar cycle refers to
the rate of activity associated with magnetic storms on the surface of the sun. the period of rotation of the sun. the apparent motion of the sun across the sky. the modulation in nuclear reactions in the center of the sun. the period of precession of the sun.
What is differentiation in planetary geology?
the process by which different types of minerals form a conglomerate rock. the process by which gravity separates materials according to density. any process by which one part of a planet's surface evolves differently from another part of the same planet's surface. any process by which a planet's surface evolves differently from another planet's surface. any process by which a planet evolves differently from its moons.
Which internal energy source is the most important in continuing to heat the interior of the Earth today?
accretion. radioactivity. tidal heating. gravitational contraction. differentiation.
Olympus Mons is
a shield volcano on Venus. a stratovolcano on Mercury. a stratovolcano on the Moon. another name for Mauna Loa, the most massive volcano on Earth. a shield volcano on Mars.
The half-life of a particular isotope of plutonium is 2.4 million years. After 7.2 million years, how much of the original amount of that isotope remains?
half. none. one eighth. one fourth. all of it.
More than half the electrical power generated in the United States comes from
hydroelectric dams. nuclear power. natural gas. biomass. coal.
How does the Greenhouse Effect work?
The higher pressure of the thick atmosphere at lower altitudes traps heat in more effectively. Greenhouse gases absorb infrared light from the Sun, which then heats the atmosphere and the surface. Greenhouse gases absorb X rays and ultraviolet light from the Sun, which then heat the atmosphere and the surface. Greenhouse gases transmit visible light, allowing it to heat the surface, but then absorb infrared light from the Earth, trapping the heat near the surface. Ozone transmits visible light, allowing it to heat the surface, but then absorbs most of the infrared heat, trapping the heat near the surface.
Which of the following statements is evidence against the fission theory for the moon's origin?
The compositions of the Earth and Moon are slightly different. The moon's surface shows evidence of cratering. It would be very difficult for the Earth to have captured the Moon. The moon is moving away from the Earth at the rate of a few centimeters a year. Volcanic activity on the moon ceased billions of years ago.
Which of the following objects would show a crescent phase when viewed from Mercury?
Earth. Venus. Mars. None of these. Ceres.
The Clementine and Prospector spacecraft found evidence for
liquid water on the asteroid Gaspra. water ice on the moon. water vapor on Venus. running water on Mars. water ice on Mercury.
Two maria on the Moon are compared. The first is heavily cratered, while the second has almost no craters. What can you conclude?
The second region was formed much later. The second region has more regolith. The second region was formed much earlier. The second region was shielded from meteors by high magnetic fields. The second region is covered with softer material.
What piece of observational evidence suggests that Mercury may have a small liquid-iron core?
It has a magnetic field. It has a high density. It has a small mass. It has a high surface temperature. It has a heavily cratered surface.
Which of the following is not a factor in determining whether a body in the solar system retains an atmosphere?
The composition of the atmospheric gases. The escape velocity. The rate of rotation. The distance from the Sun. The surface gravity.
Atmospheric pressure at the surface of Venus is
almost non-existent. about 1% that at the surface of the Earth. nearly the same as the Earth's atmospheric pressure. about 90 times that at the surface of the Earth. unknown since we have not explored the lower atmosphere of Venus.
Which of the following did the Magellan spacecraft not find on Venus?
Continent-sized uplands. Rift valleys. Impact caters. Shield volcanoes in eruption. Narrow lava channels.
Global warming by atmospheric CO2 causes the greatest temperature increase on which planet?
Mars. Mercury. Pluto. Earth. Venus.
What are the two opposing theories to explain how the heat from the interior of Venus is released?
Major impacts and ongoing volcanism. Ongoing volcanism versus catastrophic melting of a thick lithosphere. Major impacts versus catastrophic melting of a thick lithosphere. Plate tectonics versus major impacts. Plate tectonics versus magnetic braking.
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