MULTIPLE
CHOICE. Choose the one alternative that
best completes the statement or answers the question.
1) What do we mean when we say that the Sun is in
gravitational equilibrium?
A) The hydrogen
gas in the Sun is balanced so that it never rises upward or falls downward.
B) The Sun
maintains a steady temperature.
C) This is another
way of stating that the Sun generates energy by nuclear fusion.
D) There is a
balance within the Sun between the outward push of pressure and the inward pull
of gravity.
E) The Sun always
has the same amount of mass, creating the same gravitational force.
2) What are the appropriate units for the Sun's luminosity?
A) watts B) joules C) meters D) Newtons E) kilograms
3) Which layer of the Sun do we normally see?
A) photosphere
B) corona
C) chromosphere
D) convection zone
E) radiation zone
4) Sunspots are cooler than the surrounding solar
surface because
A) they are
regions where convection carries cooler material downward.
B) strong magnetic
fields slow convection and prevent hot plasma from entering the region.
C) magnetic fields
trap ionized gases that absorb light.
D) there is less
fusion occurring there.
E) magnetic fields
lift material from the surface of the Sun, cooling off the material faster.
5) How do human-built nuclear power plants on
Earth generate energy?
A) chemical
reactions
B) nuclear fusion
C) nuclear fission
D) converting
kinetic energy into electricity
E) converting
gravitational potential energy into electricity
6) Suppose you put two protons near each other.
Because of the electromagnetic force, the two protons will
A) collide.
B) remain stationary.
C) attract each
other.
D) repel each
other.
E) join together
to form a nucleus.
7) Studies of sunquakes, or helioseismology,
have revealed that
A) the Sun
vibrates only on the surface.
B)
"sunquakes" are caused by similar processes that create earthquakes
on the Earth.
C) the Sun
generates energy by nuclear fusion.
D) our
mathematical models of the solar interior are fairly accurate.
E) neutrinos from
the solar core reach the solar surface easily.
8) Why are neutrinos so difficult to detect?
A) because there
are so rare
B) because they
have no mass
C) because they
move at, or close to, the speed of light
D) because they
rarely interact with matter
E) We don't know:
this is the essence of the solar neutrino problem.
9) What processes are involved in the sunspot
cycle?
A) gravitational
contraction of the Sun
B) wave motions in
the solar interior
C) variations of
the solar thermostat
D) the winding of
magnetic field lines due to differential rotation
10) A star's luminosity is the
A) apparent
brightness of the star in our sky.
B) surface
temperature of the star.
C) lifetime of the
star.
D) total amount of
light that the star will radiate over its entire lifetime.
E) total amount of
light that the star radiates each second.
11) If the distance between us and a star is
doubled, with everything else remaining the same, the luminosity
A) is decreased by
a factor of four, and the apparent brightness is decreased by a factor of four.
B) is decreased by
a factor of two, and the apparent brightness is decreased by a factor of two.
C) remains the
same, but the apparent brightness is decreased by a factor of two.
D) the luminosity
remains the same, but the apparent brightness is decreased by a factor of four.
E) is decreased by
a factor of four, but the apparent brightness remains the same.
12) The spectral sequence in order of decreasing
temperature is
A) OFBAGKM.
B) OBAGFKM.
C) OBAFGKM.
D) ABFGKMO.
E) BAGFKMO.
13) Which of the following best describes the axes
of a Hertzsprung\'2DRussell (H\'2DR) diagram?
A) surface
temperature on the horizontal axis and luminosity on the vertical axis
B) mass on the
horizontal axis and luminosity on the vertical axis
C) surface
temperature on the horizontal axis and radius on the vertical axis
D) mass on the
horizontal axis and stellar age on the vertical axis
E) interior
temperature on the horizontal axis and mass on the vertical axis
14) On a Hertzsprung\'2DRussell diagram, where
would we find stars that are cool and luminous?
A) upper right B)
lower right C) upper left D) lower left
15) On a Hertzsprung\'2DRussell diagram, where on
the main sequence would we find stars that have the greatest mass?
A) upper right B)
lower right C) upper left D) lower left
16) On a Hertzsprung\'2DRussell diagram, where
would we find white dwarfs?
A) upper right B)
lower right C) upper left D) lower left
17) A star of spectral type G lives approximately
how long on the main sequence?
A) 1,000 years
B) 10,000 years
C) 1 million years
D) 100 million
years
E) 10 billion
years
18) Cluster ages can be determined from
A) main sequence
fitting.
B) main sequence
turnoff.
C) pulsating
variable stars.
D) spectroscopic
binaries.
E) visual
binaries.
19) Which two energy sources can help a star
maintain its internal thermal pressure?
A) nuclear fusion
and gravitational contraction
B) nuclear fission
and gravitational contraction
C) nuclear fusion
and nuclear fission
D) chemical
reactions and gravitational contraction
E) nuclear fusion
and chemical reactions
20) What happens to the core of a star after a
planetary nebula occurs?
A) It contracts
from a protostar to a main-sequence star.
B) It breaks apart
in a violent explosion.
C) It becomes a
white dwarf.
D) It becomes a
neutron star.
E) none of the
above
21) Compared to the star it evolved from, a white
dwarf is
A) hotter and
brighter.
B) hotter and
dimmer.
C) cooler and
brighter.
D) cooler and
dimmer.
E) the same
temperature and brightness.
22) What happens when the gravity of a massive
star is able to overcome neutron degeneracy pressure?
A) The core
contracts and becomes a white dwarf.
B) The core
contracts and becomes a ball of neutrons.
C) The core
contracts and becomes a black hole.
D) The star
explodes violently, leaving nothing behind.
E) Gravity is not
able to overcome neutron degeneracy pressure.
23) Which event marks the beginning of a
supernova?
A) the onset of
helium burning after a helium flash in a star with mass comparable to that of
the Sun
B) the sudden
outpouring of X rays from a newly formed accretion disk
C) the sudden
collapse of an iron core into a compact ball of neutrons
D) the beginning
of neon burning in an extremely massive star
E) the expansion
of a low-mass star into a red giant
1) Answer: D
2) Answer: A
3) Answer: A
4) Answer: B
5) Answer: C
6) Answer: D
7) Answer: D
8) Answer: D
9) Answer: D
10) Answer: E
11) Answer: D
12) Answer: C
13) Answer: A
14) Answer: A
15) Answer: C
16) Answer: D
17) Answer: E
18) Answer: B
19) Answer: A
20) Answer: C
21) Answer: B
22) Answer: C
23) Answer: C