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Astro 001 Test #3 fall 2002 Name_____________________ Sect_____
100 points = 100% Estimated to be this test:
(1) (four points) If you were classifying the planets by size only, you might make three classes.
What planets would be in each class?
(2) (Four points) Which planets have rings?
(3) (Four points) Would a small planet be more likely to have hydrogen or carbon dioxide in its
atmosphere? Explain.
(4) (SIx points) Please distinguish among meteoroids, meteors, and meteorites.
(5) (Four points) What is a blink comparator and for what is it used?
(6) (Four points) Describe the nature and types of cometary tails : How many
are there and which way do they point? A sketch might be appropriate.
(7) (Four points) Describe a comet indicating its basic parts, perhaps by a sketch.
(8) (Four points) Enumerate (list) and briefly describe the main processes of heat transfer. For
two points extra answer which ones are operating for the Sun?
(9) (Four points) Which is the core of the Sun, a solid, liquid, gas, or plasma (hot gas with the
electrons stripped from the atoms)? Please explain.
(10) (Four points) Is it probable that Pluto is a former moon of Neptune? Why or why not?
For two points each, please define carefully the following seven terms. If appropriate you may
draw diagrams connected with what you write:
(1) asteroid:
(2) escape velocity:
(3) meteoroid:
(4) ion:
(5) pressure:
(6) hydrostatic equilibrium:
(7) fusion (nuclear):
Multiple choice: Please make the most appropriate choice. Place your final answer on the
scantron sheet using a number 2 pencil. You may work with the question in the booklet first to
decide your best answer. There are two points per question:
(1) Compared to Jovian planets, terrestrial planets have a
A. lower density.
B. more rapid rotation.
C. more rocky composition.
D. larger size.
E. [More than one of the above.]
(2) Saturn is one of the _________ planets.
(a) Jovian
(b) Inferior
(c) Inner
(d) Minor
(3) Compared to terrestrial planets, Jovian planets have a
A. lower density.
B. more rapid rotation.
C. more rocky composition.
D. larger size.
E. [More than one of the above.]
(4) The only planet whose orbit is more eccentric than Mercury's is
A. Pluto.
B. Earth.
C. Saturn.
D. Venus.
E. Neptune.
(5) The mass of Jupiter was first calculated
A. [Two of the other answers.]
B. using its angular size and distance from the Earth.
C. using data from spacecraft flybys.
D. using its distance from the Sun and its revolution period.
E. by analysis of the motion of its moons.
(6) Most asteroids orbit the Sun
A. between Mars and Jupiter.
B. between Earth and Mars.
C. beyond the orbit of Saturn.
D. between Jupiter and Saturn.
E. [None of the above. No general statement can be made.]
(7) The escape velocity from the top of Earth’s atmosphere is
the escape velocity from
the surface of the Moon.
A. less than
B. the same as
C. greater than
D. [No general statement can be made, for the escape velocity depends upon temperature.]
(8) Evolutionary theories now account for the slow rotation rate of the Sun by pointing to
A. the slowing effect on the Sun of the solar wind.
B. friction within the gases involved, which would prevent the Sun from rotating fast.
C. the effect of the inner planets on the Sun.
D. the effect of the large planetsparticularly Jupiteron the Sun.
E. the conservation of angular momentum, which predicts a slowly rotating Sun when it
formed.
(9) Whether a planet or moon has an atmosphere depends upon the planet’s (or moon’s)
A. orbital speed.
B. temperature.
C. escape velocity.
D. [Both A and C above.]
E. [Both B and C above.]
(10) The connection between comets and meteors is demonstrated when one sees
A. sporadic meteors on almost any night.
B. a comet in one part of the sky and meteors in another part of the sky on the same night.
C. a predictable shower of meteors.
D. [None of the above; there is no connection.]
(11) Pluto’s mass has been calculated from
A. its effect on passing spacecraft.
B. its effect on passing asteroids.
C. the motion of Charon.
D. [All of the above.]
E. [None of the above.]
(12) The discovery of asteroids depends on the fact that, compared to the stars, the asteroids
A. look bigger.
B. look brighter.
C. move.
D. vary in brightness.
E. are a different color.
(13) The Kirkwood gaps result from
A. radiation pressure from the Sun.
B. the previous passage of a comet through the asteroid belt.
C. regular gravitational pull from the largest of Jupiter’s moons.
D. regular gravitational pulls from Jupiter.
E. previous explosions of asteroids at points in the asteroid belt.
(14) Which of the following statements best describes cometary orbits?
A. They are circular, lying in the plane of the ecliptic.
B. They lie between the orbits of Mars and Jupiter.
C. They are elongated ellipses tens to hundreds of astronomical units across.
D. They are within the orbit of Mercury.
(15) The nucleus of most comets is
A. much smaller than the Earth.
B. slightly smaller than the Earth.
C. slightly larger than the Earth.
D. much larger than the Earth.
(16) The Oort cloud is located
A. between the orbits of Mars and Jupiter.
B. just beyond Pluto’s orbit.
C. far beyond the orbit of Pluto.
D. at about the distance of the nearest star.
(17) Meteor showers are caused by
A. the Earth crossing the asteroid belt.
B. a comet’s nucleus striking the atmosphere.
C. the eccentricity of the Earth’s orbit.
D. meteorite impacts on the Earth’s surface.
E. the Earth crossing a meteoroid stream.
(18) The Sun’s energy is generated by
A. gravitational contraction.
B. nuclear fission.
C. hydrogen fusion.
D. helium fusion.
E. chemical reactions.
(19) The photosphere is
A. the layer of the Sun where energy is created from mass.
B. the outermost layer of the Sun.
C. the layer of the Sun that we see when viewing the Sun.
D. the layer of the Sun in which we see granulation.
E. [Both C and D above.]
(20) Sunspots are areas on the sun that are
A. hotter than their surrounds.
B. cooler than their surroundings.
C. brighter than their surroundings.
D. [Both A and B above.]
E. [Both B and C above.]
F.
(21) The energy produced in nuclear reactions in the Sun results from
A. friction as the nuclei crash together.
B. heat produced from the electrical effects of the reactions.
C. the increase in mass of the particles due to the reactions.
D. the decrease in mass of the particles due to the reactions.
(22) Why is a high temperature needed for energy production in the core of the Sun?
A. Hydrogen will not combine with oxygen at a low temperature.
B. Energy is needed to overcome electrical repulsion.
C. Electrons will not recombine at low temperatures.
D. The force of gravity is greater at high temperatures.
E. Speeds are less at high temperature, so there is more time for reactions between nuclei.
(23) During a total solar eclipse, the Sun’s atmosphere becomes visible. Why?
A. It is brighter during an eclipse because of light reflected from the moon.
B. The light reemitted after absorption becomes visible because the brighter Sun is blocked
out.
C. The atmosphere becomes hotter during an eclipse.
D. [The statement is not true.]
(24) The total luminosity of the Sun can be calculated from its
A. rotation period and temperature.
B. rotation period and diameter.
C. diameter and distance from the Earth.
D. diameter and the solar energy at Earth’s distance.
E. distance from Earth and the solar energy detected at Earth’s distance.
(25) Two factors that determine the pressure of a gas are
A. the speed of the molecules and the particle density.
B. the speed of the molecules and the gas’s temperature.
C. nuclear reactions in the gas and its temperature.
D. chemical reactions in the gas and its temperature.
E. [Both C and D above.]
(26)The primary source of energy for the Sun is a series of nuclear reactions in which
A. four hydrogen nuclei fuse to form a helium nucleus.
B. a helium nucleus fissions to form four hydrogen nuclei.
C. uranium nuclei fission to form several other elements.
D. two nuclei fuse to form uranium or plutonium.
E. oxygen nuclei combine to form more massive nuclei.