Question 1·   When Venus is at inferior conjunction, it is   An.docx

Question 1
· When Venus is at inferior conjunction, it is Answer
·
· 1.
· at its smallest distance from the Earth.
·
· 2.
· traveling at its greatest speed.
·
· 3.
· at its greatest angle from the Sun as seen from the Earth.
·
· 4.
· at its greatest distance from the Earth.
·
2 points
Question 2
· In the geocentric model of the solar system, which one of
the following phases of Venus should be visible from Earth?
Answer
·
· 1.
· gibbous phase between third quarter and full
·
· 2.
· full
·
· 3.
· new
·
· 4.
· gibbous phase between first quarter and full
·
2 points

Question 3
· When viewed from the Earth, the celestial sphere (the
background of stars) moves east to west on a daily basis. This
motion is caused by the Answer
·
· 1.
· revolution of the Earth around the Sun.
·
· 2.
· rotation of the Earth on its axis.
·
· 3.
· motion of the stars around the galactic center.
·
· 4.
· motion of the Sun through the Galaxy.
·
2 points
Question 4
· In the geocentric model for the solar system developed by
Ptolemy, to what does the word epicycle refer? Answer
·
· 1.
· small circle about which a planet moves while the center of
this circle moves
· around the Earth
·
· 2.
· large circle (orbit) that carries the planet around the Earth
while the planet itself
· is moving in a smaller circle
·
·
· 3.
· complete cycle of planetary motions after which the motions

repeat themselves
· (almost) exactly
·
·
· 4.
· length of time from when the planet is farthest from the Earth
to the next time it
· is farthest from the Earth
·
2 points
Question 5
· Suppose that, at the same time on the same night, we see
two supernovas (exploding stars) explode in the night sky. If
one is in the Andromeda Galaxy, 2 million light-years away
from us, and the other is in the galaxy M82, 6 million light-
years away from us, which of the following statements
concerning the actual explosion times of these supernovas is
correct? Answer
·
· 1.
· We cannot tell which star actually exploded first because both
stars are so far away.
·
· 2.
· The supernova in the Andromeda Galaxy actually occurred
before the one in M82.
·
· 3.
· The supernova in the Andromeda Galaxy actually occurred
after the one in M82.
·
· 4.
· We know both stars exploded at the same time because we saw
the explosions at
· the same time.
·

2 points
Question 6
· A rocket that is accelerated by the force from the ejection
of large quantities of hot gases represents an example of which
physical law originally stated by Newton? Answer
·
· 1.
· Newton's first law of motion, concerned with state of rest or
uniform motion
·
· 2.
· Newton's law of elliptical motion of planets
·
· 3.
· Newton's law of universal gravitation
·
· 4.
· Newton's third law of motion, concerning action and reaction
forces
·
2 points
Question 7
· In the years after Newton published his laws of motion, it
was found that the observed positions of the planet Uranus did
not match the predictions of Newton's theory. The reason for
this turned out to be Answer
·
· 1.
· the gravitational influence of a previously unknown planet.
·
· 2.
· inaccuracies in Newton's laws (later corrected by general
relativity).
·
· 3.
· inaccuracies in the observations.

·
· 4.
· the perturbing effects of previously unknown satellites
(moons) of Uranus.
·
2 points
Question 8
· A certain star is found to be 340 ly from the Earth.
Expressed in parsecs, the distance is approximately Answer
·
· 1.
· 105 pc.
·
· 2.
· 0.340 kpc (kiloparsecs).
·
· 3.
· 750 pc.
·
· 4.
· 1100 pc.
·
2 points
Question 9
· From the Earth, we observe occasional retrograde motion
in the motion of Answer
·
· 1.
· only the inner planets: Mercury and Venus.
·
· 2.
· only the outer planets: Mars and beyond.
·
· 3.
· all the planets.
·

· 4.
· all the planets and the Moon.
·
2 points
Question 10
· What is the angle between the line from the Earth to
Mercury and the line from Mercury to the Sun when Mercury is
at greatest elongation? Answer
·
· 1.
· 0°
·
· 2.
· 90°
·
· 3.
· 180°
·
· 4.
· anywhere between 0° and 180°, depending on the particular
planetary alignment
·
2 points
Question 11
· For many years, the Palomar telescope (5-m diameter) in
California was the largest telescope in the world; it has now
been surpassed by both Keck telescopes (each of diameter 10 m)
in Hawaii. How much greater is the light-gathering power of a
Keck telescope than that of the Palomar telescope? Answer
·
· 1.
· 4 times greater
·
· 2.
· 1.4 times greater
·

· 3.
· 8 times greater
·
· 4.
· 2 times greater
2 points
Question 12
· A Cassegrain reflecting telescope is constructed using a
Answer
·
· 1.
· curved primary mirror followed by a series of both plane and
curved mirrors
· that channel the light to a remote location fixed with respect
to the Earth.
·
·
· 2.
· concave primary mirror and a flat, diagonal secondary mirror
mounted at a
· 45° angle to the telescope axis.
·
·
· 3.
· concave primary mirror and concave secondary mirror that
reflects light back
· through a hole in the primary mirror.
·
·
· 4.
· concave primary mirror followed by a smaller convex
secondary mirror that
· reflects light back through a hole in the primary mirror.
·
2 points

Question 13
· Which of the following techniques is the key factor in a
telescope that uses adaptive optics to correct for atmospheric
distortion of images, or “seeing”? Answer
·
· 1.
· Computer-controlled motors adjust the position and shape of
one of the small
· mirrors within the optics many times per second.
·
·
· 2.
· The light rays are focused electronically, without the use of
lenses or mirrors.
·
· 3.
· Computer-controlled motors rapidly adjust the orientation and
position of the
· separate primary mirrors in a multiple-mirror telescope
(MMT).
·
·
· 4.
· A corrector lens compensates for image distortion by
electronic control of its shape.
·
2 points
Question 14
· How much more efficient in collecting incoming photons
is the modern charge-coupled device (CCD) compared to a
typical photographic plate? Answer
·
· 1.
· more than 100 times
·
· 2.

· about 35 times
·
· 3.
· a little better than a factor of 2
·
· 4.
· about 10 times
·
2 points
Question 15
· The first astronomical radio source was detected and
identified in the year Answer
·
· 1.
· 1897.
·
· 2.
· 1967.
·
· 3.
· 1932.
·
· 4.
· 1945.
·
2 points
Question 16
· What fraction of the light falling on a piece of
photographic film is typically wasted (does NOT contribute to
the formation of the image)? Answer
·
· 1.
· 18%
·
· 2.
· 45%

·
· 3.
· 2%
·
· 4.
· 98%
·
2 points
Question 17
· Which of the following telescopes consists of a concave,
spherical primary mirror and a glass corrector plate to correct
for the spherical aberration in the primary? Answer
·
· 1.
· Schmidt telescope
·
· 2.
· Cassegrain telescope
·
· 3.
· refracting telescope
·
· 4.
· Newtonian telescope
·
2 points
Question 18
· Which of the following sequences of electromagnetic
radiation is correct, in order of increasing energy of the photons
(or quanta)? Answer
·
· 1.
· visible light, UV radiation, X rays, gamma rays
·
· 2.
· radio waves, microwaves, gamma rays, UV radiation

·
· 3.
· visible light, microwave, radio waves, infrared rays
·
· 4.
· gamma rays, radio waves, X rays, infrared rays
·
2 points
Question 19
· An electrical spark, such as lightning, generates
electromagnetic radiation over a wide range of wavelengths.
How much longer will a pulse of radio energy take to travel
between two detector stations 100 m apart than will a pulse of
ultraviolet radiation from the same spark? Answer
·
· 1.
· The time will be identical because both pulses travel at the
speed of light.
·
· 2.
· much shorter because long wavelength radiations travel faster
·
· 3.
· just a little longer because the high frequency UV radiation
travels faster than the
· low frequency radio waves
·
·
· 4.
· much longer because radio waves have much longer
wavelengths and therefore
· travel slower
·
2 points
Question 20
· The two ranges of electromagnetic radiation for which the

Earth's atmosphere is reasonably transparent are Answer
·
· 1.
· UV and radio waves.
·
· 2.
· X rays and visible radiation.
·
· 3.
· visible and far infrared radiation.
·
· 4.
· visible and radio radiation.
·
2 points
Question 21
· Which very significant fact concerning the spectra
produced by hot gases, such as elements heated on the solar
surface (Fraunhofer, with the solar spectrum) or in a flame
(Bunsen and Kirchhoff, with laboratory spectra), was
discovered in the 1800s? Answer
·
· 1.
· Each chemical element produces its own characteristic pattern
of spectral lines that
· remains fixed as the temperature increases.
·
·
· 2.
· Chemical elements emit spectral lines that move continuously
toward the blue end
· of the spectrum as the gas temperature increases.
·
·
· 3.
· All chemical elements produce the same set of spectral

emission or absorption
· lines, but their relative emission intensities differ; hence
elements are distinguishable
· from each other by their spectra.
·
·
· 4.
· The higher the temperature, the greater the redshift of the
emitted spectral lines.
·
2 points
Question 22
· The hot, dense gas existing on the Sun emits energy
Answer
·
· 1.
· at all wavelengths, with a peak at one particular wavelength
(color).
·
· 2.
· with the same intensity at all wavelengths. Earth's atmosphere
absorbs radiation at both short and long visible wavelengths to
produce the observed spectrum.
·
· 3.
· only at certain wavelengths and not at other wavelengths.
·
· 4.
· mostly at the longest and shortest wavelengths, with a
minimum in between.
·
2 points
Question 23
· The majority of the mass of ordinary matter resides in the
Answer
·

· 1.
· electron clouds around the nuclei of atoms.
·
· 2.
· electrons and the nuclei, shared about equally.
·
· 3.
· electromagnetic energy stored in the atom, from E = mc2.
·
· 4.
· nuclei of atoms.
·
2 points
Question 24
· Ionization of an atom occurs when Answer
·
· 1.
· an electron drops from a higher energy level to the ground
state.
·
· 2.
· the nucleus is split, or fission occurs.
·
· 3.
· an electron is lifted from the ground state to an excited level.
·
· 4.
· an electron is removed from the atom.
·
2 points
Question 25
· The position of an element in the periodic table is directly
related to the Answer
·
· 1.
· number of electrons in the atomic nucleus and hence to its

negative charge.
·
· 2.
· total number of protons and neutrons in the atomic nucleus.
·
· 3.
· mass of the nucleus of the atom.
·
· 4.
· number of protons in the atomic nucleus and hence to its
positive charge.
·
2 points
Question 26
· If a continuous spectrum of ultraviolet radiation passes
through a tube of cool hydrogen gas, what happens to its
spectrum? Answer
·
· 1.
· All the radiation passes unhindered except the Lyman Lα
wavelength, which is
· absorbed by the atoms.
·
·
· 2.
· All the radiation passes through the tube unhindered because
the hydrogen gas
· is cool and cannot absorb energy.
·
·
· 3.
· Some of the radiation at all wavelengths is absorbed, reducing
the intensity at all
· wavelengths uniformly.
·
·

· 4.
· All the radiation passes through the tube unhindered except at
the specific
· wavelengths of the Lyman series, Lα, Lβ, and so on, which are
absorbed by the atoms.
·
2 points
Question 27
· A violet photon has a wavelength of 400 nm. What is its
energy? Answer
·
· 1.
· 4.97 × 10–19 joules
·
· 2.
· 5.21 × 10–19 joules
·
· 3.
· 3.62 × 10–19 joules
·
· 4.
· 6.88 × 10–19 joules
·
2 points
Question 28
· To a physicist, a blackbody is defined as an object that
Answer
·
· 1.
· always appears to be black, whatever its temperature.
·
· 2.
· always emits the same spectrum of light, whatever its
temperature.
·
· 3.

· absorbs all radiation that falls on it.
·
· 4.
· reflects all radiation that falls on it, never heating up and
always appearing black.
·
2 points
Question 29
· The Doppler effect is the Answer
·
· 1.
· increase in the observed wavelength of light if the light source
is moving toward you.
·
· 2.
· increase in the observed wavelength of light if the source of
light is moving away from you.
·
· 3.
· change in the wavelength of peak emission of light when the
source temperature changes.
·
· 4.
· splitting of spectral lines into two or more wavelengths
because the source of the
· light is in a strong magnetic field.
·
2 points
Question 30
· An atom of hydrogen undergoes a collision with another
atom in a hot gas in which the energy of collision is about 11
eV. What is the likely outcome of this collision in terms of the
atom? (See Figure 4-11, Comins and Kaufmann, Discovering the
Universe, 8th ed.) Answer
·
· 1.

· The electron in the atom will be excited to the second excited
level, n = 3,
· and de-excitation will generate either a Lα UV Lyman photon
or an Hα visible
· and a Lα UV photon.
·
·
· 2.
· The electron in the atom will be excited to the first excited
level, and de-excitation
· to the ground state will produce a visible photon of Balmer
Hα light.
·
·
· 3.
· The electron in the atom will be excited to the first excited
level, n = 2. Its return
· to the ground state will produce a Lα UV Lyman photon.
·
·
· 4.
· The electron of the hydrogen atom will be excited beyond the
ionization level
· (n = ∞); the atom will be ionized, and the electron will leave
the atom completely.
·
2 points
Question 31
· What is the cause of an annular eclipse? Answer
·
· 1.
· The Moon's position in its orbit is near apogee, its farthest
point from Earth.
·
· 2.
· The Moon's position in its orbit is near perigee, its nearest

point to Earth.
·
· 3.
· Earth's position in its orbit is near aphelion, its farthest point
from the Sun.
·
· 4.
· Earth's position in its orbit is near perihelion, its nearest point
to the Sun.
·
2 points
Question 32
· The bright star Procyon is seen to rise on the eastern
horizon at 10:00 P.M. on December 1. At approximately what
time will this star rise one week later, on December 8?
Answer
·
· 1.
· 10:28 P.M.
·
· 2.
· 9:53 P.M.
·
· 3.
· 10:00 P.M.
·
· 4.
· 9:32 P.M.
·
2 points
Question 33
· The Moon is seen to keep one face toward the Earth at all
times. If viewed from a point directly above the plane of the
planetary system, how does it have to rotate to maintain this
alignment? Answer
·

· 1.
· The moon must rotate once per month, or once per orbit
around the Earth.
·
· 2.
· The moon must rotate once per year as the Earth and the Moon
orbit the Sun together.
·
· 3.
· The moon must rotate once per day to maintain its direction
toward the Earth.
·
· 4.
· The moon must not rotate at all because we always see the
same face from Earth.
·
2 points
Question 34
· The length of time for the Moon to move from new Moon
to new Moon is known as one synodic month. Compared to one
full orbital period with respect to the star background, or one
sidereal month, the synodic month is Answer
·
· 1.
· about 2 days shorter.
·
· 2.
· about twice as long.
·
· 3.
· about 2 days longer.
·
· 4.
· exactly the same length.
·
2 points

Question 35
· For an observer at a fixed location on the Earth, the angle
between the north celestial pole and an observer's horizon
depends on the Answer
·
· 1.
· observer's latitude (north or south of the equator).
·
· 2.
· time of day.
·
· 3.
· time of year.
·
· 4.
· observer's longitude (east or west of Greenwich).
·
2 points
Question 36
· Where would you have to be to see the north celestial pole
directly over your head (i.e., in your zenith)? Answer
·
· 1.
· at the North Pole of the Earth
·
· 2.
· on the equator
·
· 3.
· at a position about 1° away from the Earth's South Pole, to
account for precession
·
· 4.
· at the South Pole of the Earth
·
2 points

Question 37
· If the daytime sky were not so bright, how fast would we
see the Sun move across it with respect to the stars as it moves
through one full circle in one year? Answer
·
· 1.
· about 1° per day
·
· 2.
· exactly 24° per day or 1° per hour
·
· 3.
· The Sun would never appear to move with respect to the stars
in the sky.
·
· 4.
· about 15° per hour
·
2 points
Question 38
· 1 arc minute is equal to Answer
·
· 1.
· 1/60°.
·
· 2.
· 1/3,600°.
·
· 3.
· 1/60 arc second.
·
· 4.
· 1/60 of a full circle.
·
2 points
Question 39

· The most recent correction to the calendar to keep the
yearly date in tune with the seasons (resulting in the present
calendar) was instituted by Answer
·
· 1.
· Galileo.
·
· 2.
· Pope Gregory XIII.
·
· 3.
· Sir Isaac Newton.
·
· 4.
· Julius Caesar.
·
2 points
Question 40
· Which of the following planets will be seen as crescent-
shaped from the Earth at certain times in its orbit? Answer
·
· 1.
· Mars
·
· 2.
· Jupiter
·
· 3.
· Venus
·
· 4.
· Uranus
·
2 points
Question 41
· When Saturn is at its farthest distance from the Earth, it is

at Answer
·
· 1.
· opposition.
·
· 2.
· conjunction.
·
· 3.
· greatest elongation (about 47° from the Sun).
·
· 4.
· inferior conjunction.
·
2 points
Question 42
· What fraction of the light falling on a piece of
photographic film is typically wasted (does NOT contribute to
the formation of the image)? Answer
·
· 1.
· 45%
·
· 2.
· 98%
·
· 3.
· 18%
·
· 4.
· 2%
·
2 points
Question 43
· When observing planetary motions from the Earth, the
phrase direct motion refers to the Answer

·
· 1.
· slow westward motion of the planet from night to night
compared to the background stars.
·
· 2.
· apparent westward motion of the planet (and the Sun, the
Moon, and stars) across the
· sky due to the rotation of the Earth.
·
·
· 3.
· motion of the planet directly toward or away from the Earth in
certain parts of the
· planet's orbit.
·
·
· 4.
· slow eastward motion of the planet from night to night
·
2 points
Question 44
· 1 arc second is equal to Answer
·
· 1.
· 1/3,600°.
·
· 2.
·
· 3.
· 1/60°.
·
· 4.

·
2 points
Question 45
· The main reason for placing a telescope and scientific
equipment into an aircraft to carry out infrared astronomy is
to Answer
·
· 1.
· avoid the absorption of the IR radiation by water vapor.
·
· 2.
· avoid stray IR radiation from the warm Earth and its
occupants.
·
· 3.
· obtain photographs of resolution higher than can be obtained
on the ground.
·
· 4.
· obtain longer observing times on specific sources by moving
in the direction of
· the Earth's rotation.
·
2 points
Question 46
· From a location in the northern hemisphere, the pole star
always appears at an angle above the northern horizon equal to
Answer
·
· 1.
· 180° plus the longitude of the location.
·
· 2.
· the latitude of the location.
·
· 3.

· the longitude of the location.
·
· 4.
· 90° minus the latitude of the location.
·
2 points
Question 47
· The number of degrees in a semicircle is Answer
·
· 1.
· 57.3.
·
· 2.
· 90.
·
· 3.
· 360.
·
· 4.
· 180.
·
2 points
Question 48
· In single-telescope astronomical systems, either optical or
radio, the Answer
·
· 1.
· smaller the main mirror or lens or radio dish aperture in
general, the sharper the image.
·
· 2.
· longer the focal length of the primary mirror or lens or radio
dish, the sharper the image.
·
· 3.
· longer the wavelength, the sharper the image.

·
· 4.
· larger the main mirror or lens or radio dish aperture in
general, the sharper the image.
·
2 points
Question 49
· Newton stated that if a force were applied to an object in
space, the resultant acceleration would depend on the
Answer
·
· 1.
· initial speed of the object.
·
· 2.
· initial position of the object.
·
· 3.
· mass of the object.
·
· 4.
· size of the object.
·
2 points
Question 50
· Which of the following optical elements or combinations
make up a Newtonian telescope? Answer
·
· 1.
· one concave and one flat mirror
·
· 2.
· two curved mirrors, one concave, the second convex
·
· 3.
· one concave focusing mirror

·
· 4.
· two lenses, to produce an image the correct way around
Question 1
1.
What is the explanation for the bright cells of photospheric
gases that make up the cellular granulation pattern seen on the
visible surface of the Sun?
Answer
1.
The cells are the base of a circulation pattern that extends from
the photosphere to the outer corona.
2.
The cells are the tops of blobs of hot gas that have risen from
the Sun's convective zone.
3.
Each cell is a region of strong magnetic field, which compresses
and heats the gas within it.
4.
The cells are regions of nuclear energy generation in the Sun's
photosphere.
1 points
Question 2
1.
The difference between an umbral eclipse and a penumbral
eclipse is
Answer

1.
entirely dependent on your viewing position on Earth.
2.
the distance of the Moon above or below the ecliptic.
3.
whether the Moon is farther from the Sun than Earth is or
whether it is closer to the Sun than Earth is.
4.
whether Earth's rotation axis is tilted toward or away from the
Moon during the eclipse.
1 points
Question 3
1.
The temperature of the corona of the Sun is
Answer
1.
about twice as hot as the photosphere, 12,000 K.
2.
very cool because it is the farthest part of the Sun from the heat
source.
3.
very hot, about 106 K.
4.
about the same as that of the photosphere, 5800 K.
1 points
Question 4
1.
Spicules on the solar surface are
Answer

1.
streams of solar coronal material, usually seen only during a
total solar eclipse.
2.
intense eruptions from sunspot groups and active regions,
associated with solar flares.
3.
jets of gas surging out of the photosphere of the Sun into the
chromosphere, usually at supergranule boundaries.
4.
curtainlike structures hanging over sunspot regions.
1 points
Question 5
1.
One distinctive feature that is visible on the “surface” of Jupiter
through a telescope from the Earth is
Answer
1.
Olympus Mons.
2.
the northern auroral oval.
3.
the Cassini Division.
4.
the Great Red Spot.
1 points
Question 6
1.

Intense magnetic fields have been found to exist in sunspots by
the observation of what specific physical effect?
Answer
1.
observation of ionized atoms in the region of the sunspots
2.
measurement of the relative strengths of spectral absorption
lines of gases in the sunspot
3.
Zeeman effect, the splitting of spectral absorption lines
4.
Doppler shift of light from sunspots
1 points
Question 7
1.
The ancient Greek thinker whose model of the universe came to
dominate the medieval world was
Answer
1.
Zorba.
2.
Archimedes.
3.
Alexander.
4.
Ptolemy.
1 points
Question 8

1.
An object is in an orbit caused by its gravitational attraction to
the Sun. This orbit
Answer
1.
must be a parabola.
2.
must be an ellipse.
3.
must be a hyperbola.
4.
might be an ellipse, a parabola, or a hyperbola.
1 points
Question 9
1.
Approximately what fraction of its main-sequence lifetime has
the Sun completed at the present time (see Table 12-2, Comins
and Kaufmann, Discovering the Universe,8th ed.)?
Answer
1.
about 3/4
2.
less than 10%
3.
about 1/2
4.
about 1/4
1 points

Question 10
1.
At approximately what time does the new Moon rise?
Answer
1.
close to sunrise
2.
sunset
3.
midnight
4.
midday
1 points
Question 11
1.
One prominent feature recently identified within many energetic
close binary star systems as a result of their mutual interaction
and mass exchange is
Answer
1.
a cool dust cloud surrounding the whole star system, hiding it
from visible view.
2.
planetary formation between the stars, emitting IR radiation
from molecular constituents and dust.
3.
the beginnings of spiral arms, showing the possible origin of
spiral galaxies.

4.
two oppositely directed high-speed jets of matter leaving the
system.
1 points
Question 12
1.
The temperature of the Sun throughout its radius and including
its atmosphere
Answer
1.
increases and decreases several times between the center and
the surface, then decreases through the atmosphere.
2.
is almost constant from the center to the surface but falls
abruptly above the visible surface.
3.
decreases smoothly outward from the center, gradually merging
at the “top” of the atmosphere into the cold of the interplanetary
medium.
4.
decreases outward from the center but then increases again in
the atmosphere.
1 points
Question 13
1.
The four giant moons of Jupiter were discovered by
Answer
1.
Newton, in seventeenth-century England.
2.

Galileo, in seventeenth-century Italy.
3.
the Pioneer spacecraft, the first spacecraft to visit Jupiter.
4.
Ptolemy, in ancient Greece.
1 points
Question 14
1.
Which of the following sentences correctly states the
significance of Galileo's observation that Jupiter has satellites
(moons)?
Answer
1.
The observation showed that Jupiter must be four times the size
of the Earth (because Jupiter has four moons and the Earth has
one).
2.
The observation showed that bodies can orbit an object other
than the Earth.
3.
The observation showed that Jupiter must orbit the Sun, not the
Earth.
4.
The observation was interesting but had no other particular
significance.
1 points
Question 15
1.
A total lunar eclipse can last more than an hour and a half, but a
total solar eclipse never lasts more than 7 1/2 minutes. Why the

difference?
Answer
1.
Both Earth and the Moon move clockwise in their orbits, as seen
from the north. Thus during a solar eclipse Earth and Moon are
moving in opposite directions, and during a lunar eclipse they
are moving in the same direction.
2.
Earth's shadow at the Moon's distance is much larger than the
Moon's shadow at Earth's distance. As Earth rotates, this narrow
lunar shadow sweeps quickly over any given spot.
3.
A total solar eclipse always occurs when Earth is at perihelion;
it is moving fastest at that time.
4.
A total solar eclipse always occurs when the Moon is at perigee;
it is moving fastest at that time.
1 points
Question 16
1.
The temperature in the atmosphere of Venus (see Figure 7-11,
Comins and Kaufmann, Discovering the Universe, 8th ed.)
Answer
1.
increases smoothly with increasing altitude.
2.
is almost constant with altitude.
3.
has a complicated structure reaching several maxima and

minima at various altitudes.
4.
decreases smoothly with increasing altitude.
1 points
Question 17
1.
The 21-cm line is one of the most important wavelengths in
radio astronomy. It is produced mainly in
Answer
1.
hot O and B stars.
2.
ionized hydrogen.
3.
emission nebulae.
4.
neutral hydrogen.
1 points
Question 18
1.
When we look out into the plane of the Milky Way Galaxy, how
far can we see?
Answer
1.
about 100,000 ly
2.
infinitely far
3.

less than 1000 ly
4.
about 10,000 ly
1 points
Question 19
1.
The “helium flash” occurs in a 2-solar-mass star when
Answer
1.
the core temperature becomes sufficiently high for helium
fusion for the first time.
2.
hydrogen fusion ceases abruptly, leaving only the fusion of
helium to generate energy.
3.
the core heats up from helium fusion and the gas does not
expand to cool down and stabilize the temperature because the
gas properties are controlled by degenerate electrons.
4.
convection within the star carries helium to the surface, where it
shows its own characteristic spectrum for the first time.
1 points
Question 20
1.
An atom is now known to consist of a
Answer
1.
positively charged crystal structure with electrons moving
within it.

2.
small, positively charged black hole with electrons held in
orbits around it by intense gravitational forces.
3.
small, massive, electrically charged core surrounded by
electrons.
4.
uniform distribution of positively charged matter with electrons
embedded in it.
1 points
Question 21
1.
Newton stated that a constant force, continuously applied to a
body in space, will give it a
Answer
1.
constant velocity.
2.
headache.
3.
constant acceleration.
4.
change of position from one state of rest to another state of rest.
1 points
Question 22
1.
The nearest quasar is
Answer
1.

among the nearby superclusters of galaxies.
2.
in the Milky Way Galaxy.
3.
in the Local Group of galaxies.
4.
barely visible at the remote edge of the observable universe.
1 points
Question 23
1.
How is chromatic aberration most often corrected in a modern
refracting telescope?
Answer
1.
by grinding the lens surfaces into a parabolic shape
2.
by using a prism to recombine the colors into white light
3.
by painting the inside of the telescope jet black to minimize
reflections
4.
by using a combination of two lenses made from different types
of glass
1 points
Question 24
1.
What is the name for a theory that describes the overall
structure of the universe in which the Earth is located?
Answer

1.
cosmology
2.
astronomy
3.
field theory
4.
astrology
1 points
Question 25
1.
Where on the Sun do solar flares occur?
Answer
1.
only within sunspot groups
2.
only in a narrow band along the solar equator
3.
only at the polar regions
4.
only in coronal holes
1 points
Question 26
1.
What experimental evidence do we have for the direct
transformation of energy into matter?
Answer

1.
blueshift of light because of the motion of its source
2.
relativistic increase in mass of an object when it is moving very
rapidly
3.
Conversion of gamma-ray photons into electrons and
antielectrons (i.e., positrons)
4.
increase in the force upon a body when it is accelerated upward
(e.g., in an elevator)
1 points
Question 27
1.
When did the universe cool to a temperature of 3 K?
Answer
1.
1 second after the start of the Big Bang, when pair production
ceased
2.
3 minutes after the start of the Big Bang, when primordial
nuclear reactions ceased
3.
500,000 years after the Big Bang, when the universe became
transparent to radiation
4.
very recently
1 points
Question 28

1.
In which order (from earliest to latest) did the following people
make their major contributions to astronomy?
Answer
1.
Kepler, Copernicus, Brahe, Newton
2.
Brahe, Copernicus, Newton, Kepler
3.
Copernicus, Brahe, Kepler, Newton
4.
Copernicus, Kepler, Brahe, Newton
1 points
Question 29
1.
The most noticeably elliptical planetary orbit is the orbit of
Answer
1.
Mars.
2.
Earth.
3.
Uranus.
4.
Mercury.
1 points
Question 30
1.

Which of the following features appears in the spectrum of the
solar corona and indicates very high gas temperatures?
Answer
1.
bright emission from the hydrogen Balmer line, Hα, at the red
end of the spectrum
2.
intense continuous emission in the infrared part of the spectrum
3.
ntense emission lines from highly ionized atoms, such as iron
4.
dark absorption lines from hydrogen, calcium, and iron on a
continuous bright spectrum
1 points
Question 31
1.
The planet with the greatest mean density is
Answer
1.
Earth.
2.
Neptune.
3.
Mercury.
4.
Jupiter.
1 points
Question 32

1.
What was the most important difference between the
development of Isaac Newton's theory of planetary motion and
that of Johannes Kepler?
Answer
1.
Newton lived in a freer political climate, whereas Kepler risked
house arrest if his theory opposed the Bible or Aristotle.
2.
Newton developed his theory from basic physical assumptions,
whereas Kepler simply adjusted his theory to fit the data.
3.
Newton based his theory on accurate telescopic observations,
whereas Kepler used observations made by eye.
4.
Newton lived in England, which is famous for clear skies,
whereas Kepler lived on the continent, which is notorious for
bad weather.
1 points
Question 33
1.
The core (inner and outer) of Earth extends over what fraction
of its radius?
Answer
1.
almost 80%
2.
about
3.

roughly
4.
less than 10%
1 points
Question 34
1.
The surprising observational fact about quasars is that they
appear to
Answer
1.
be associated with ancient supernova explosions.
2.
produce the energy output of greater than 100 galaxies in a
volume similar to that of our planetary system.
3.
be the largest known structures in the universe, although they
produce only modest amounts of energy.
4.
be moving rapidly toward us while emitting large amounts of
energy.
1 points
Question 35
1.
Of the following objects in the solar system, which one has the
greatest orbital inclination (orbit at the greatest angle to that of
Earth)?
Answer
1.
Pluto

2.
Mercury
3.
Jupiter
4.
Mars
1 points
Question 36
1.
The space between stars is known to contain
Answer
1.
large quantities of dust that absorb and scatter light but no gas,
either atomic or molecular.
2.
variable amounts of gas but no dust, which forms only in
planetary systems near stars.
3.
gas, both atomic and molecular, and dust.
4.
a perfect vacuum.
1 points
Question 37
1.
What observations of the Martian surface led Lowell to the
conclusion that intelligent life-forms existed on Mars?
Answer
1.
lakes and rivers of water flowing from polar icecaps and

detected by strong specular reflection of sunlight
2.
melting icecaps, a network of linear features that look like
canals, and varying dark surface marking assumed to be
vegetation
3.
geometrical structures and patterns that are apparently the
remains of buildings and cities
4.
sculpted mountains in the shape of humanoid heads, obviously
carved to announce the presence of intelligent life to distant
observers
1 points
Question 38
1.
Main-sequence stars apparently are not larger than a few
hundred solar masses. The reason stars of larger mass do not
exist is that
Answer
1.
the thermonuclear reactions in such stars proceed so rapidly that
the stars explode.
2.
their temperature becomes so high that they are disrupted by the
pressure of radiation inside them.
3.
interstellar clouds of greater mass break up to become binary or
multiple-star systems, not single stars.
4.

such stars contract directly to become planetlike objects.
1 points
Question 39
1.
In the simplified version of Kepler's third law, P2 = a3, the
units of the orbital period P and the semimajor axis of the
ellipse amust be, respectively,
Answer
1.
seconds and meters.
2.
years and meters.
3.
years and light-years.
4.
years and astronomical units.
1 points
Question 40
1.
The source of the water found in the form of ice near Mercury's
north and south poles is
Answer
1.
a former global ocean, now almost entirely evaporated and lost
to space.
2.
rainfall early in Mercury's history, when the planet had a dense
atmosphere.
3.

unknown at the present time.
4.
comet impacts.
1 points
Question 41
1.
What is the typical temperature inside the dense core of a giant
molecular cloud that is collapsing to form a star?
Answer
1.
1000 K
2.
100 K
3.
10 K
4.
less than 1 K
1 points
Question 42
1.
Earth's thermosphere is the
Answer
1.
intermediate atmospheric layer in which ultraviolet light from
the Sun is absorbed by ozone (O3) molecules.
2.
outermost atmospheric layer in which ultraviolet light from the
Sun ionizes atoms.

3.
region of the magnetosphere in which trapped high-energy
charged particles spiral along magnetic field lines.
4.
layer of molten iron and nickel below the mantle.
1 points
Question 43
1.
Why are carbonaceous chondrites thought to be original
material that formed in the early solar nebula?
Answer
1.
The minerals of a carbonaceous chondrite contain up to 20%
water, which would have evaporated away if the chondrite had
been strongly heated.
2.
Carbonaceous chondrites show a Widmanstätten pattern, which
indicates slow condensation from gaseous material.
3.
Carbonaceous chondrites consist mostly of carbon, which was
the dominant substance condensing in the outer solar nebula.
4.
Carbonaceous chondrites consist almost entirely of ice, which
would have sublimed away by now if this were not the first time
the chondrite was passing close to the Sun.
1 points
Question 44
1.
How is water ice able to remain on the surface of Mercury,
despite the planet's close proximity to the Sun?
Answer

1.
The water ice is continuously replenished by fresh impacts from
comets.
2.
The water ice exists as permafrost below the thermally
insulating surface and is exposed only by occasional impacts.
3.
The water ice is permanently shielded from the Sun by crater
walls at the north and south poles.
4.
The water ice is continuously replenished by condensation of
water vapor from volcanoes.
1 points
Question 45
1.
What property is shared by the Earth and Europa, one of
Jupiter's large moons?
Answer
1.
The Earth and Europa both have warm oceans of water.
2.
The Earth and Europa have both been shown to harbor
intelligent life in their oceans.
3.
The Earth and Europa both have thick atmospheres of nitrogen
and oxygen.
4.
The Earth and Europa are about the same physical size.

1 points
Question 46
1.
The distance to the bright quasar 3C 273 is estimated to be
Answer
1.
just beyond the Milky Way.
2.
2 billion ly.
3.
3 million ly.
4.
20,000 ly.
1 points
Question 47
1.
Spacecraft measurements indicate that the surface of Venus is
dominated by
Answer
1.
basalt, a volcanic rock formed when lava solidifies on the
surface.
2.
schist, a metamorphic rock formed by the deformation of other
rocks by pressure and heat.
3.
sandstone, a sedimentary rock formed on Venus by sand grains
deposited by wind.

4.
granite, a plutonic rock formed when lava solidifies deep below
the surface.
1 points
Question 48
1.
In what crucial way is the atmosphere of Earth very different
from the atmospheres of Venus and Mars?
Answer
1.
Earth's atmospheric temperature is relatively cool, whereas both
Venus and Mars have very high atmospheric temperatures.
2.
Carbon dioxide (CO2) gas is the dominant component in the
atmospheres of Venus and Mars, but it is only a minor
constituent in Earth's atmosphere.
3.
Hydrogen (H) gas makes up a large fraction of the atmospheres
of both Venus and Mars, but it is absent from Earth's
atmosphere.
4.
Methane (CH4) gas is present in large quantities on Venus and
Mars, but it is only a trace gas on Earth.
1 points
Question 49
1.
What is helioseismology?
Answer
1.
study of vibrations in the Sun's interior

2.
study of the Sun's tidal effects in causing earthquakes
3.
detailed study of the shape of the Sun
4.
study of the Sun's response to collisions with grazing comets
1 points
Question 50
1.
105/105 =
Answer
1.
0
2.
1
3.
10
4.
1012
1 points
Question 51
1.
The heat energy that powers tectonic activity on the surface of
Earth originates deep in Earth's core. How does this energy
move from the core to the surface?
Answer
1.
steady flow of hot magna from Earth's core through cracks in
the mantle to the lithosphere

2.
conduction throughout the entire mantle
3.
conduction through the solid lower mantle and convection in the
upper mantle (asthenosphere)
4.
convection throughout the entire mantle
1 points
Question 52
1.
What was the declination of the Sun on March 21 this year?
Answer
1.
180°
2.
It would have no unique value but could be any angle between
+23.5° and –23.5°.
3.
23.5°
4.
0°
1 points
Question 53
1.
The surface of the Sun near its edge appears dimmer and cooler
than at the center of the disk when viewed in visible light
because we see
Answer

1.
light from the edge that has had to pass through more of the
absorbing chromosphere and corona and is thereby reduced in
intensity.
2.
less deeply into the Sun near the edge than at disk center and
temperature increases with depth.
3.
less deeply into the Sun near the edge than at disk center and
temperature decreases with depth.
4.
deeper into the Sun near the edge than at disk center and
temperature increases with depth.
1 points
Question 54
1.
A particular star has an absolute magnitude of +12 and a
spectral class of A5. Using Figures 11-7 and 11-10 of Comins
and Kaufmann, Discovering the Universe, 8th ed., how would
this star be classified?
Answer
1.
A5 III
2.
A5 I
3.
A-type white dwarf
4.
A5 V

1 points
Question 55
1.
An astronomer studying a galaxy finds that its spectrum shows
only old, low-mass, Population II stars, and photographs of the
galaxy show little or no interstellar gas or dust. What kind of
galaxy is this astronomer studying?
Answer
1.
spiral galaxy
2.
An irregular galaxy
3.
barred spiral galaxy
4.
elliptical galaxy
1 points
Question 56
1.
The Oort cloud is
Answer
1.
a random distribution of short-period comets extending from
inside the orbit of Jupiter to approximately the orbit of
Neptune.
2.
a flat or donut-shaped distribution of distant comets around the
Sun, extending out about 500 AU.
3.

a spherical distribution of distant comets around the Sun,
extending out about 50,000 AU.
4.
another name for the asteroid belt.
1 points
Question 57
1.
The light from a distant cloud of gas and dust looks distinctly
red to the naked eye. When a spectrum is taken it is found that
many wavelengths which would normally be expected to be in
the middle of the spectrum have been shifted into the long
wavelength end of the spectrum. Thus the red color in this
situation is due to
Answer
1.
interstellar reddening, the Balmer spectrum of hydrogen, or the
Doppler effect.
2.
the Balmer spectrum of hydrogen.
3.
the Doppler effect.
4.
interstellar reddening.
1 points
Question 58
1.
What is the name of a small jet of rising gas in the
chromosphere of the Sun?
Answer
1.

spicule
2.
flare
3.
granule
4.
prominence
1 points
Question 59
1.
Where are bright, young O and B stars most likely to be found
in the Milky Way Galaxy?
Answer
1.
between spiral arms, where there is less absorbing material
2.
inside spiral arms
3.
in globular clusters
4.
in the outermost regions of the disk, where much of the “dark
matter” is located
1 points
Question 60
1.
A star rises at 8 P.M., moves across the sky (crossing high
overhead), and then sets at
Answer

1.
noon.
2.
8 A.M.
3.
2 A.M.
4.
midnight.
1 points
Question 61
1.
What is the solar wind?
Answer
1.
storm of waves and vortices on the Sun's surface generated by a
solar flare
2.
material from the corona, accelerated out into space
3.
constant flux of photons from the Sun's visible surface
4.
circulation of gases in the chromosphere, between the equator
and the poles of the Sun
1 points
Question 62
1.
On the basis of the recent interpretation of geological evidence,
the impact of a 10-km-diameter asteroid on the surface of Earth
would be very likely to

Answer
1.
create significant damage near the impact site but have
relatively little lasting worldwide effect.
2.
completely destroy life on Earth.
3.
shatter Earth into fragments.
4.
disrupt the global ecology and cause the extinction of a large
percentage of all species living on Earth.
1 points
Question 63
1.
After the material in the core of a massive star has been
converted to iron by thermonuclear reactions, further energy can
be released to heat the core only by
Answer
1.
gravitational contraction.
2.
the absorption of neutrinos.
3.
thermonuclear fusion of iron into heavier elements.
4.
nuclear fission, or splitting of nuclei.
1 points
Question 64

1.
Who was the first astronomer to use a telescope for viewing the
sky?
Answer
1.
Newton
2.
Galileo
3.
Ptolemy
4.
Brahe
1 points
Question 65
1.
What is the only way to measure the mass of a star accurately?
Answer
1.
It is not possible to measure the mass of a star.
2.
Measure its distance using trigonometric parallax and its
brightness using photometry.
3.
Measure its gravitational effect on another object.
4.
Measure its spectral type and luminosity class, then use the H-R
diagram.
1 points

Question 66
1.
Which of the following phenomena is NOT seen on Jupiter's
satellite Io?
Answer
1.
volcanic plumes
2.
impact craters
3.
lava flows
4.
sulfur dioxide frost
1 points
Question 67
1.
What appears to be the “impact history” of cratering on the
Moon?
Answer
1.
early period of heavy bombardment, then very light
bombardment to the present
2.
heaviest bombardment when the Moon first formed, gradually
decreasing to light bombardment today
3.
short periods of heavy bombardment alternating with long
periods of light bombardment throughout the Moon's life

4.
more or less constant bombardment from the earliest times to
the present
1 points
Question 68
1.
Using the distance to the Coma cluster of galaxies and the
Hubble relation (using an intermediate value of the Hubble
constant H0 equal to 80 km/s per million parsecs; see Figure 16-
21, Comins and Kaufmann, Discovering the Universe, 8th ed.),
what would be the approximate wavelength shift of the Balmer
Hα spectral line at 656.3 nm emitted by a galaxy in the cluster
because of the general expansion of the universe? (See also
Astronomer's Toolbox 16-1 of Comins and
Kaufmann,Discovering the Universe, 8th ed.)
Answer
1.
1.61 nm
2.
1.61 × 106 nm
3.
16.1 nm
4.
161.0 nm
1 points
Question 69
1.
What proportion of visible stars in our nighttime sky are
members of multiple-star systems, such as binary stars?
Answer
1.

close to 100%
2.
only about 1/4, or 25%
3.
less than 1%
4.
2/3, or almost 70%
1 points
Question 70
1.
In the southern hemisphere, day and night are of equal duration
on about
Answer
1.
January 1, by definition.
2.
June 21.
3.
March 21.
4.
December 21.
1 points
Question 71
1.
What is the important difference between modern neutrino
detectors and the chlorine-argon detection system of previous
decades?
Answer

1.
The new detectors are able to detect all three neutrino types, not
just those originally emitted from the Sun.
2.
The new detectors are smaller and thus can be built more
cheaply.
3.
The new detectors can be tuned to detect neutrinos of any
energy.
4.
The new detectors are in orbit above our atmosphere, thus
avoiding the loss of neutrinos absorbed in Earth's atmosphere.
1 points
Question 72
1.
In the 1860s, James Clerk Maxwell carried out important
investigations on the nature of light when he
Answer
1.
proved mathematically that light could be described by
oscillating electric and magnetic fields.
2.
showed that a prism through which light passed added a
spectrum of colors to the light.
3.
demonstrated the wave nature of light by passing light through
two slits and obtaining a pattern of bright and dark bands on a
screen that he correctly interpreted as interference between the
two light beams.

4.
demonstrated that white light was made up of colors that could
be split by a prism and that these colors were not produced by
the glass through which the light passed.
1 points
Question 73
1.
The amount of light reflected by a planet or other object is its
Answer
1.
apparent magnitude.
2.
albedo.
3.
emissivity.
4.
color index.
1 points
Question 74
1.
Sometimes high tides are lower than at other times. What name
is given to the lowest high tides?
Answer
1.
pep tides
2.
neap tides
3.
spring tides

4.
rip tides
1 points
Question 75
1.
What were the dominant gases in Earth's earliest atmosphere
after it first formed?
Answer
1.
carbon dioxide and nitrogen
2.
hydrogen and helium
3.
nitrogen and oxygen
4.
methane and ammonia
1 points
Question 76
1.
Which wavelength region of the electromagnetic spectrum is
taken up by visible light?
Answer
1.
400 nm to 700 nm
2.
100 nm to 400 nm
3.
4000 nm to 7000 nm

4.
1200 nm to 1500 nm
1 points
Question 77
1.
One or more natural satellites (moons) do NOT orbit which
planets?
Answer
1.
Mercury and Mars
2.
Mercury, Venus, and Mars
3.
Mars and Venus
4.
Mercury and Venus
1 points
Question 78
1.
If we characterize the age of a surface by the age of the oldest
feature that has been dated there, then the ages of the following
surfaces are, from youngest to oldest,
Answer
1.
Venus, the Earth, and the Moon.
2.
the Earth, the Moon, and Venus.
3.

Venus, the Moon, and the Earth.
4.
the Earth, Venus, and the Moon.
1 points
Question 79
1.
The average distance from the Earth to the Sun, 149,600,000
km, can be written in shorthand notation as
Answer
1.
1.496 × 109 km.
2.
1.496 × 108 km.
3.
1.496 × 106 km.
4.
1.496 × 107 km.
1 points
Question 80
1.
The light intensity from a particular star remains essentially
constant except for short and regular decreases and increases by
a fixed amount. What is the explanation for this phenomenon?
Answer
1.
A variable star is pulsating in size, temperature, and intensity.
2.
A massive, dark planet is periodically passing in front of the
star's visible surface.

3.
Shells of absorbing gas and dust are being periodically ejected
from the star's surface and are subsequently dispersing into
space.
4.
One star is regularly eclipsing its companion as they move in
mutual orbits whose plane is close to the line of sight.
1 points
Question 81
1.
Over an interval of 6 months, the tilt of the Earth's spin axis
with respect to the background stars will change by
Answer
1.
47°.
2.
180°.
3.
23.5°.
4.
0°.
1 points
Question 82
1.
One of the first people to look for radio signals from
extraterrestrial civilizations was
Answer
1.
Frank Drake.

2.
Martin Schwarzschild.
3.
Jocelyn Bell.
4.
Arno Penzias.
1 points
Question 83
1.
Accretion of matter in an interstellar cloud leads to
Answer
1.
explosion of this matter when it is attracted to and falls onto the
surfaces of stars.
2.
the formation of molecules from atomic gases.
3.
a protostar.
4.
a supernova explosion since accretion is a nuclear process.
1 points
Question 84
1.
The structure of Ganymede, a Galilean satellite of Jupiter, is
thought to be
Answer
1.
an iron core, a rocky mantle, and a liquid ocean with a dirty ice

surface.
2.
mostly or entirely rock, with no firm evidence of an iron core,
and active volcanoes on its surface.
3.
about half rock and half ice, with rock at the center and ice
outside.
4.
a large rocky core with a thin layer (100 km thick) of ice and
water over it.
1 points
Question 85
1.
When observing planetary motions from the Earth, the
phrase direct motion refers to the
Answer
1.
slow eastward motion of the planet from night to night
2.
motion of the planet directly toward or away from the Earth in
certain parts of the planet's orbit.
3.
apparent westward motion of the planet (and the Sun, the Moon,
and stars) across the sky due to the rotation of the Earth.
4.
slow westward motion of the planet from night to night
1 points

Question 86
1.
A particular photon has a wavelength of 450 nm and a second
one has a wavelength of 580 nm. Which of the following
statements about the energies of these two photons is true?
Answer
1.
The 450-nm photon has the higher energy.
2.
The 580-nm photon has the higher energy.
3.
The photon from the higher-intensity light source has the higher
energy (regardless of wavelength).
4.
All photons have the same energy, regardless of wavelength.
1 points
Question 87
1.
Stellar parallax is the
Answer
1.
apparent shift seen in the position of a nearby star against more
distant stars as the Earth orbits the Sun.
2.
inferred change in the distance to a star as its light is dimmed
by passing through an interstellar cloud.
3.
difference between the apparent and absolute magnitudes of a
star.

4.
circular or elliptical motion of a star in a binary system as the
two stars orbit each other.
1 points
Question 88
1.
In the Hertzsprung-Russell diagram, how does the position of a
typical star change while it is at the main-sequence phase of its
evolution?
Answer
1.
A star's position on the main sequence is determined only by its
mass, not its age, so stars do not move along the main sequence
during evolution.
2.
Stars move from upper right to lower left while they are on the
main sequence.
3.
Massive stars (4 solar masses) move toward the upper left as
their luminosity increases, while lower-mass stars move toward
the lower right as their temperature decreases.
4.
Stars move from upper left to lower right while they are on the
main sequence.
1 points
Question 89
1.
When the northern hemisphere is experiencing winter, the
Answer
1.

Earth is farther from the Sun than it is during the northern
summer.
2.
Earth is closer to the Sun than it is during northern summer.
3.
southern hemisphere is experiencing winter also.
4.
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.
1 points
Question 90
1.
Which of the following statements comparing the Sun to the
giant stars is NOT true? (Refer to Figure 11-10, Comins and
Kaufmann, Discovering theUniverse, 8th ed.)
Answer
1.
The giant stars have smaller absolute magnitudes than the Sun.
2.
The giant stars are more luminous than the Sun.
3.
The giant stars are larger than the Sun.
4.
The giant stars are hotter than the Sun.
1 points
Question 91
1.
Why did the Soviet spacecraft survive for only a few minutes on
the Venusian surface?

Answer
1.
They were attacked and destroyed by native inhabitants, but the
space agency is not telling the world.
2.
The conditions of extreme pressure, corrosive atmosphere, and
high temperatures severely damaged it.
3.
They landed in very rugged terrain and were not able to land
upright, and they became damaged when they toppled over.
4.
They landed very fast because there was insufficient atmosphere
to slow down their descent.
1 points
Question 92
1.
The one significant observation Galileo made through his home-
built telescope that convinced him that the planets revolved
around the Sun was the
Answer
1.
appearance of mountains and craters on the Moon.
2.
discovery of rings around the planet Saturn.
3.
appearance of Venus following a cycle of phases, from crescent
through quarter and gibbous phases to full.
4.

appearance of the Milky Way as a mass of individual stars.
1 points
Question 93
1.
The clouds in the atmosphere of Venus consist primarily of
Answer
1.
dust particles.
2.
water.
3.
droplets of carbon dioxide.
4.
droplets of sulfuric acid.
1 points
Question 94
1.
How was the planet Uranus discovered?
Answer
1.
Uranus was discovered by mathematical prediction using
Newton's laws.
2.
Uranus happened to pass close to Jupiter in the sky and was
discovered by an astronomer studying Jupiter.
3.
Uranus was discovered accidentally during a telescopic survey
of the sky.

4.
No one knows—Uranus has been known since ancient times.
1 points
Question 95
1.
Which of the following statements about the Moon is true?
Answer
1.
Earth can never be seen from one side of the Moon.
2.
The Moon does not rotate on its axis.
3.
The Moon can never pass through Earth's shadow.
4.
One side of the Moon is always in darkness.
1 points
Question 96
1.
What scientific method was first used to discover the rings
around Uranus?
Answer
1.
direct photography of the rings from the Earth
2.
occultation of a star as the planet and rings moved in front of it
3.
spacecraft exploration of the planet
4.

X-ray photography from the Einstein satellite
1 points
Question 97
1.
What was the first direct evidence that some other solar-type
stars might have planets?
Answer
1.
faint pinpoints of light slowly circling some stars, as seen
through the new 8- and 10-meter telescopes
2.
cyclic Doppler shift variations in the spectra of several stars
3.
slightly wavy path of a star through space, as if the star were
being tugged by an orbiting planet
4.
warped disks of dust and gas around some young stars
1 points
Question 98
1.
Harlow Shapley's original estimate of the distance from the Sun
to the galactic center was incorrect because it did not take
scattering by interstellar dust into account. Shapley's original
estimate was
Answer
1.
too small because gas and dust tend to reflect light into the path
of the beam, thus making stars look brighter and nearer.
2.
too large because scattering by dust made stars look redder—as

though they were highly Doppler-shifted and thus more distant.
3.
too large because light scattering and absorption by dust made
nearer stars look dim—as though they were more distant.
4.
too large because scattering by dust made stars look redder—as
though they were red giants of larger luminosity and thus
farther away.
1 points
Question 99
1.
The one component of the material of the Milky Way Galaxy
that prevents us from seeing and photographing the galactic
center at optical wavelengths is
Answer
1.
hot hydrogen gas.
2.
very cold hydrogen gas.
3.
the glare of light from nearby stars.
4.
interstellar dust.
1 points
Question 100
1.
According to Newton's laws, a force must be acting whenever
Answer
1.

the direction of an object's motion changes.
2.
time passes.
3.
an object's position changes.
4.
an object moves with some speed.

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