MULTIPLE
CHOICE. Choose the one alternative that
best completes the statement or answers the question.
1) 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
2) What happens when a star exhausts its core
hydrogen supply?
A) Its core
contracts, but its outer layers expand and the star becomes bigger and
brighter.
B) It contracts,
becoming smaller and dimmer.
C) It contracts,
becoming hotter and brighter.
D) It expands,
becoming bigger but dimmer.
E) Its core
contracts, but its outer layers expand and the star becomes bigger but cooler
and therefore remains at the same brightness.
3) What is a planetary nebula?
A) a disk of gas
surrounding a protostar that may form into planets
B) what is left of
the planets around a star after a low-mass star has ended its life
C) the expanding
shell of gas that is no longer gravitationally held to the remnant of a
low-mass star
D) the molecular
cloud from which protostars form
E) the expanding
shell of gas that is left when a white dwarf explodes as a supernova
4) 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
5) Which element has the lowest mass per nuclear
particle and therefore cannot release energy by either fusion or fission?
A) hydrogen B)
oxygen C) silicon D) iron E)
uranium
6) On
a Hertzsprung\'2DRussell diagram, where would we find stars that are cool and
dim?
A) upper right B)
lower right C) upper left D) lower left
7) What type of star is our Sun?
A) low-mass star
B)
intermediate-mass star
C) high-mass star
8) 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
9) 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.
10) 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
11) From the center outward, which of the
following lists the "layers" of the Sun in the correct order?
A) core, radiation
zone, convection zone, corona, chromosphere, photosphere
B) core, corona,
radiation zone, convection zone, photosphere, chromosphere
C) core, radiation
zone, convection zone, photosphere, chromosphere, corona
D) core,
convection zone, radiation zone, corona, chromosphere, photosphere
E) core,
convection zone, radiation zone, photosphere, chromosphere, corona
12) 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
13) The core of the Sun is
A) at the same
temperature and density as the surface.
B) at the same
temperature but denser than the surface.
C) hotter and
denser than the surface.
D) constantly
rising to the surface through convection.
E) composed of
iron.
14) 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.
15) Cluster ages can be determined from
A) main sequence
fitting.
B) main sequence
turnoff.
C) pulsating
variable stars.
D) spectroscopic
binaries.
E) visual
binaries.
16) Since
all stars begin their lives with the same basic composition, what
characteristic most determines how they will differ?
A) location where
they are formed
B) time they are
formed
C) luminosity they
are formed with
D) mass they are
formed with
E) color they are
formed with
17) Compared to the star it evolved from, a red
giant is
A) hotter and
brighter.
B) hotter and
dimmer.
C) cooler and
brighter.
D) cooler and
dimmer.
E) the same
temperature and brightness.
18) 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.
19) 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
20) 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.
21) What are the appropriate units for the Sun's luminosity?
A) watts B) joules C) meters D) Newtons E) kilograms
22) On a Hertzsprung\'2DRussell diagram, where
would we find white dwarfs?
A) upper right B)
lower right C) upper left D) lower left
23) The helium fusion process results in the
production of
A) hydrogen. B)
oxygen. C) carbon. D) nitrogen. E) iron.
24) Which is closest to the temperature of the core
of the Sun?
A) 10,000 K
B) 100,000 K
C) 1 million K
D) 10 million K
E) 100 million K
25) The spectral sequence in order of decreasing
temperature is
A) OFBAGKM.
B) OBAGFKM.
C) OBAFGKM.
D) ABFGKMO.
E) BAGFKMO.
26) 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.
27) Why does a star grow larger after it exhausts
its core hydrogen?
A) The outer
layers of the star are no longer gravitationally attracted to the core.
B) Hydrogen fusion
in a shell outside the core generates enough thermal pressure to push the upper
layers outward.
C) Helium fusion
in the core generates enough thermal pressure to push the upper layers outward.
D) Helium fusion
in a shell outside the core generates enough thermal pressure to push the upper
layers outward.
E) The internal
radiation generated by the hydrogen fusion in the core has heated the outer
layers enough that they can expand after the star is no longer fusing hydrogen.
28) 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
29) 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
30) What is the average temperature of the surface
of the Sun?
A) 1 million K B)
100,000 K C) 10,000 K D) 6,000 K E) 1,000 K
31) Which layer of the Sun do we normally see?
A) photosphere
B) corona
C) chromosphere
D) convection zone
E) radiation zone
32) The phase of matter in the Sun is
A) gas.
B) plasma.
C) liquid.
D) solid.
E) a mixture of
all of the above.
33) 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.
34) 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.
35) How does the Sun generate energy today?
A) nuclear fission
B) nuclear fusion
C) chemical
reactions
D) gravitational
contraction
E) gradually
expanding in size
36) 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.
37) 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.
38) After a supernova event, what is left behind?
A) always a white
dwarf
B) always a
neutron star
C) always a black
hole
D) either a white
dwarf or a neutron star
E) either a
neutron star or a black hole
39) Which of the following sequences correctly
describes the stages of life for
a low-mass star?
A) red giant,
protostar, main-sequence, white dwarf
B) white dwarf,
main-sequence, red giant, protostar
C) protostar, red
giant, main-sequence, white dwarf
D) protostar,
main-sequence, white dwarf, red giant
E) protostar,
main-sequence, red giant, white dwarf
40) 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
The following
questions refer to the sketch below of an H-R diagram for a star cluster.
Figure 14.2
41) Consider the star to which the arrow points.
Which of the following statements about this star is not true?
A) It is
significantly less massive than the Sun.
B) It is larger in
radius than the Sun.
C) It is brighter
than the Sun.
D) Its surface
temperature is lower than the Sun's.
E) Its core
temperature is higher than the Sun's.
1) Answer: A
2) Answer: A
3) Answer: C
4) Answer: C
5) Answer: D
6) Answer: B
7) Answer: A
8) Answer: A
9) Answer: D
10) Answer: E
11) Answer: C
12) Answer: C
13) Answer: C
14) Answer: D
15) Answer: B
16) Answer: D
17) Answer: C
18) Answer: D
19) Answer: A
20) Answer: E
21) Answer: A
22) Answer: D
23) Answer: C
24) Answer: D
25) Answer: C
26) Answer: B
27) Answer: B
28) Answer: D
29) Answer: C
30) Answer: D
31) Answer: A
32) Answer: B
33) Answer: D
34) Answer: C
35) Answer: B
36) Answer: D
37) Answer: B
38) Answer: E
39) Answer: E
40) Answer: C
41) Answer: A