HOMEWORK #3
1.
Which of the following is (are) correct?
(a) In the Sun's core, hydrogen is transformed into
helium.
(b) Using the Zeeman effect, one can measure the magnetic
fields of sunspots.
(c) The energy of the Sun's fusion reaction is carried off
mainly in the form of neutrinos.
The correct answer(s) is(are) ____________.
2.
Which of the following is (are) correct for sunspots?
(a) They generally occur in pairs with one east of the
other.
(b) They are hotter than the surrounding areas on the
Sun's surface.
(c) They occur at lower latitudes as the sunspot cycle
progresses.
The correct answer(s) is(are) ____________.
3.
Which of the following is (are) correct for the solar atmosphere?
(a) The outer layers are cooler.
(b) Solar flares occur in the photosphere.
(c) Prominences occur near the limb of the Sun.
The correct answer(s) is(are) ____________.
4.
Which of the following is (are) correct?
(a) Energy is transported from the Sun's core to its
surface primarily by a process called convection.
(b) It takes about five minutes for energy from the Sun's
core to reach its surface.
(c) The proton cycle describes the process of energy
production in the Sun's core.
The correct answer(s) is(are) ____________.
5. Which of the following is (are) necessary when determining the
distance to a star using spectroscopic parallax?
(a) apparent magnitude
(b) spectral type
(c) period
The correct answer(s) is(are) ____________.
6.
Which of the following is (are) correct?
(a) If I triple the distance to a star it will look eighty
one times fainter.
(b) Spectral class A stars have stronger absorption lines
than those with spectral class O.
(c) The luminosity class of a star is a measure of the
ionization in its atmosphere.
The correct answer(s) is(are) ____________.
7. Which of the following is (are) correct?
(a) The primary source of the Sun's energy is meteorite
infall.
(b) A stellar spectrum visible from the Earth is
an absorption spectrum.
(c) The H and R in the term, "HR Diagram", stand for
Helmholtz and Roberts.
The correct answer(s) is(are) ____________.
8.
Which of the following is (are) correct?
(a) If one star is five magnitudes greater than another
star, it is 100 times fainter than that second star.
(b) The absolute magnitude is the apparent magnitude that a
star would have at a distance of 1000 parsec.
(c) Comets have very elliptical orbits.
The correct answer(s) is(are) ____________.
9. Which of the following is (are) correct?
(a) Massive stars evolve more quickly.
(b) Protostars are larger than normal stars.
(c) A spectral type F star is cooler than one of spectral
type G.
The correct answer(s) is(are) ____________.
10. Which of the following is (are) correct?
(a) The primary reaction in the sun's core is a fission
reaction.
(b) "Limb Darkening" occurs in the Sun's photosphere.
(c) Plages and flares on the surface of the sun are
the same phenomenon.
The correct answer(s) is(are) ____________.
11. Which of the following is (are) correct?
(a) Magnetic storms occur on the Earth when the sun is near
sunspot maximum.
(b) If the stellar parallax of a star is .1 arc sec the
distance to it is 100 parsecs.
(c) Mercury always keeps the same face toward the Sun.
The correct answer(s) is(are) ____________.
12.
Which of the following is (are) correct?
(a) The surface of Venus is hot due to the "greenhouse effect".
(b) Venus is brightest in gibbous phase.
(c) Venus rotates from east to west.
13.
Which of the following is (are) correct?
(a) Olympus Mons is a large canyon on Mars.
(b) The seasons on Mars are more severe in the southern
hemishphere.
(c) Mars red color is caused by the oxidation of iron (rust).
The correct answer(s) is(are) ____________.
14.
Which of the following is (are) correct?
(a) The Kuiper belt and the Oort cloud are really the same
thing.
(b) Comets contain a lot of water.
(c) Comets and asteroids are made largely of the same
materials.
The correct answer(s) is(are) ____________.
15. Which of the following is (are) characteristic of Cepheid
variables?
(a) Their absolute magnitude depends on their period.
(b) They are found in the galactic plane.
(c) They pulse with periods of about one day or less.
The correct answer(s) is(are) ____________.
16. Which of the following is (are) correct?
(a) White dwarfs contain a super conducting material.
(b) Uranium is produced in red giant stars.
(c) The triple alpha process occurs in main sequence stars.
The correct answer(s) is(are) ____________.
17. Which of the following is (are) correct?
(a) Reddening (color excess) in a star's spectrum is
primarily caused by interstellar dust.
(b) One needs to know a star's size in order to determine
its color excess.
(c) HI regions emit 21-cm. wavelength radiation.
The correct answer(s) is(are) ____________.
18. Which of the following is (are) correct?
(a) If the turnoff point is low on the main sequence in
the color-magnitude diagram of a star cluster,
the cluster is old.
(b) Emission nebulae are referred to as HII regions.
(c) The reactions in the cores of stars are exothermic.
The correct answer(s) is(are) ____________.
19.
Which of the following is (are) correct?
(a) The color index of a cool red star is a positive number.
(b) The sun was located at the center of the "Kapteyn"
universe.
(c) Elements heavier than iron are produced in supernovae.
The correct answer(s) is(are) ____________.
20.
Which of the following is (are) correct for black holes?
(a) Electromagnetic waves slow down as they recede (move away)
from the event horizon.
(b) An observer falling into a black hole would notice
that his clock slowed down.
(c) The event horizon is defined by the Schwarzschild
radius.
The correct answer(s) is(are) ____________.
21.
Which of the following is (are) correct?
(a) All pulsars are neutron stars.
(b) Pulsars pulse at a very constant rate.
(c) The Crab pulsar has a period of less than one second.
The correct answer(s) is(are) ____________.
22.
Which of the following is (are) correct?
(a) Binary neutron stars are thought to emit gravity waves.
(b) Synchrotron radiation comes from particles traveling
slowly with respect to the speed of light.
(c) Type II Cepheid variable stars are Population II stars.
The correct answer(s) is(are) ____________.
23.
Which of the following is (are) correct?
(a) HII regions contain cold molecular hydrogen.
(b) An absorption nebula is an HI region.
(c) RR-Lyra stars frequently occur in globular clusters.
The correct answer(s) is(are) ____________.
24. Which of the following is (are) correct?
(a) All cool stars are smaller than all hot stars.
(b) Spiral galaxies have more angular momentum than
ellipticals.
(c) All white dwarf stars are older than all main
sequence stars.
The correct answer(s) is(are) ____________.
25.
Which of the following is (are) correct?
(a) Type II supernovae occur in binary systems.
(b) The period-luminosity relationship is valid only for
main sequence stars.
(c) The helium flash occurs after a star evolves off of
the main sequence.
The correct answer(s) is(are) ____________.
26.
Which of the following is (are) correct?
(a) Normal galaxies radiate primarily by synchrotron
radiation.
(b) Supernovae can occur only once in a given star.
(c) Spiral arms in a galaxy are thought to be density
waves.
The correct answer(s) is(are) ____________.
27.
Which of the following is (are) correct?
(a) The Milky Way is a spiral galaxy.
(b) We say there is "missing mass" in galaxies because we
can't see enough material to explain the gravity
that appears to hold them together.
(c) Seyfert galaxies emit spectra having broad emission
lines.
The correct answer(s) is(are) ____________.
28. If Hubble's constant is 50 km/sec/Mpc, an object receding
from us at the rate of 5000 km/sec would be _____ away.
The correct answer(s) is(are) ____________.
29.
Which of the following is (are) correct?
(a) A galactic cluster is a cluster of galaxies.
(b) The Sun is located in the halo of the Milky Way
Galaxy.
(c) BL Lacertae galaxies are active galaxies.
The correct answer(s) is(are) ____________.
30.
Which of the following is (are) correct?
(a) T Tauri stars lie in the instability strip of the HR
diagram.
(b) A globular cluster contains up to 100,000 stars.
(c) The Tully-Fischer relation uses the rotation of a
galaxy to determine its distance.
The correct answer(s) is(are) ____________.
31. "The Universe looks the same in all directions from all points
in space". This statement is called _________________.
(1)
(2)
(3)
(4)
(5)
the
the
the
the
the
cosmological principle
perfect cosmological principle
Russell-Vogt theorem
homogeneous space principle
Great Society
32.
Which of the following is (are) important in the determination
of the size of the Universe?
(a) All objects at great distances show red shifted spectra.
(b) The radius of the event horizon of a black hole is
given by the expression R = 3M.
(c) The Chandrasekhar limit.
The correct answer(s) is(are) ____________.
33.
Which of the following is (are) correct?
(a) The cosmological redshift is caused by the expansion
of space.
(b) The larger the Hubble constant (H) is, the older the
Universe.
(c) The 3 degree background radiation arose at the time of
inflation in the early universe.
The correct answer(s) is(are) ____________.
34. Which of the following pertain(s) to the term "decoupling" in the
"Big Bang" cosmology?
(a) When light breaks free from the event horizon in a
black hole.
(b) When photons no longer scattered off of electrons
which had attached themselves to ions to form
neutral atoms.
(c) When the universe became transparent to neutrinos.
The correct answer(s) is(are) ____________.
35. Which of the following is (are) correct?
(a) A spherical space is negatively curved.
(b) Since we observe all deep space objects to be receding
from us in all directions, we can conclude that we
are at the center of the Universe.
(c) The anthropic principle states that the fine-tuned
nature of the Universe suggests that it was
fashioned so that humans can exist.
The correct answer(s) is(are) ____________.
36. Which of the following pertain to inflation of the early
Universe?
(a) It was a hyper-light speed expansion of space in the
early universe.
(b) It was proposed to explain why the microwave
background (3K radiation) is so uniform.
(c) It was used to explain the irregularities in the
cosmic background radiation.
The correct answer(s) is(are) ____________.
37. Presuming that the initial stars all had identical mass, list the
ages of the following stars in chronological order (starting with the
youngest)?
(a)
(b)
(c)
(d)
protostar
Cepheid variable
main sequence star
red giant star
The correct answer(s) is(are) ____________.
38.
Which of the following best states the Russell-Vogt theorem?
(a) Fundamental proton-proton chain fusion reactions yield
neutrinos.
(b) The ultimate result of a protostar collapse is uniquely
determined by its mass and composition.
(c) Gravitational radiation is emitted by massive
revolving bodies.
(d) Supernovae occur only in stars having mass greater than
eight solar masses.
The correct answer(s) is(are) ____________.
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Homework #3, AST 1002.doc