1. A stone is heated until it glows red. It emits
(a) an emission line spectrum.
(b) an absorption line spectrum.
(c) a continuous spectrum.
(d) an excited state spectrum.
(e) a ground state spectrum.
2. A star has a surface temperature of 3 000 K, which type of radiation does
it emit most prolifically? (It may be helpful to recall that the temperature of
the Sun is almost 6000 K.)
(a) gamma rays
(b) infrared radiation
(c) radio waves
(d) visible light
(e) ultraviolet radiation
3. Which of the following wavelengths of electromagnetic radiation has
photons of the highest energy?
(a) 1 kilometer
(b) 1 centimeter
(c) 1 meter
(d) 0.1 millimeter
(e) 5 millimeters
4. Which of the following statements is FALSE?
(a) The absorption lines produced by an element have the
same wavelengths as emission lines from the same element.
(b) Atoms in the ground state can only emit photons and not absorb them.
(c) The emission or absorption of a photon by an atom is associated with a
transition to a new energy state.
(d) Atoms of different elements have different sets of energy levels.
(e) Hot, low density gas viewed against a dark background produces an
emission line spectrum.
5. In what way is the spectrum of light from a star changed when it passes
through a diffuse cloud of cool interstellar gas?
(a) It becomes an emission line spectrum.
(b) The continuous spectrum gets brighter.
(c) A few narrow absorption lines are added.
(d) Emission lines are added if the gas moves towards us and absorption
lines are added if the gas is moving away.
(e) Absorption lines are added if the gas moves towards us and emission
lines are added if the gas is moving away.
6. The balance between pressure and gravity in a main sequence star is known
as
(a) the mass-luminosity relation
(b) Kirchoff's law
(c) hydrostatic equilibrium
(d) Solar oscillations
(e) the neutrino problem
7. The Sun generates its energy by
(a) fusing hydrogen to helium in
its core.
(b) fusing hydrogen to helium at its surface.
(c) the fission of uranium in its core.
(d) the fission of hydrogen in its core.
(e) gravitational contraction.
8. Why doesn't the Sun explode like a nuclear bomb?
(a) The mass of material pressing down on the Sun's core
regulates the reactions occurring there
(b) It is impossible for nuclear reactions to consume 1 solar mass of
material in one brief explosion
(c) The Sun does not contain uranium, which is necessary for explosions
(d) Nuclear explosions can only be triggered by artificial, technological
means
(e) Actually, the Sun is exploding uncontrollably
9. Which of the following statements is correct?
(a) O type stars are cooler than F type stars.
(b) A type stars are hotter than M type stars.
(c) K type stars are hotter than B type stars.
(d) The Sun is a B type star.
(e) Stars of the same spectral class are all at the same distance.
10. You measure the apparent brightness in two colors of G2 main sequence
stars in five clusters. The most distant cluster is the one in which these
stars are the
(a) faintest
(b) brightest
(c) reddest
(d) bluest
(e) smallest
11. In a standard Hertzsprung-Russell diagram, the
axes of the plot represent (in effect)
(a) luminosity versus temperature
(b)
(b) radius versus mass
(c) luminosity versus radius
(d) mass versus temperature
(e) Hertzsprungs versus Russells
12. Which of the following statements is UNTRUE?
(a) The more massive a main sequence star, the more brightly
it shines.
(b) The more massive a main sequence star, the larger its diameter.
(c) Fainter main sequence stars can have a wide range of ages.
(d) Massive main sequence stars live longer than low mass ones.
(e) Main sequence stars all burn hydrogen to helium in their cores.
13. If two stars have the same temperature but different radii, then in a Hertzsprung-Russell diagram the larger star will be
(a) horizontally to the left of the
smaller star
(b) horizontally to the right of the smaller star
(c) vertically above the smaller star
(d) vertically below the smaller star
(e) you cannot tell their relative positions
without also knowing the ages of the stars
14. Stars in the faint, red part of the Hertzsprung-Russell
diagram are
(a) high mass main sequence stars
(b) distant red giant stars
(c) low mass main sequence stars
(d) nearby white dwarf stars
(e) moderate mass main sequence stars
15. In order to determine the masses of the individual stars in a binary we
need to measure the
(a) orbital period and average
separation of the stars only.
(b) orbital period and distance of each star from
the center of mass.
(c) orbital speed of each star and the distance of
the binary from Earth.
(d) relative brightnesses
and the distance of the binary from Earth.
(e) relative temperatures of the two stars and the
orbital period.
16. How does a star's lifetime depend upon its mass?
(a) The lifetime of a star is independent of its mass (b)
(b) The more massive a star, the longer its lifetime
(c) The more massive a star, the shorter its lifetime (d)
(d) Moderate mass stars (like the Sun) have longer lifetimes than either
high or low mass stars
(e) Moderate mass stars (like the Sun) have shorter lifetimes than either
high or low mass stars
17. Which of the following is NOT true of a globular star cluster?
(a) All of the cluster stars have approximately the same
age.
(b) All of the cluster stars have approximately the same composition.
(c) All of the cluster stars have approximately the same mass.
(d) All of the cluster stars have approximately the same distance from us.
(e) The cluster is held together by gravitational forces.
18. In a group of stars all formed at the same time, the more massive stars
will
(a) be found on the lower right
part of the main sequence.
(b) become red supergiants
while less massive stars are still on the main sequence.
(c) still be protostars
when less massive stars have reached the main sequence.
(d) never initiate nuclear reactions, and become
brown dwarfs.
(e) be more likely to join the intergalactic weight
watchers association.
19. Interstellar gas is composed of mostly
(a) hydrogen and helium.
(b) oxygen and nitrogen.
(c) hydrogen and iron.
(d) hydrogen and oxygen.
(e) helium and carbon.
20. In a dark dust cloud
(a) the gas is mostly in molecular
form.
(b) the density is much lower than for average
interstellar matter.
(c) the temperature is generally much higher than
for average interstellar matter.
(d) there is no gas, only dense concentrations of
dust.
(e) there are corners that the janitor missed.
21. A collapsing molecular cloud
(a) forms a single, massive star.
(b) forms many stars, both high mass and low mass.
(c) never forms stars.
(d) will form stars only if it is sufficiently hot.
(e) will form stars only if it rotates sufficiently
rapidly.
22. The time taken for a 1 solar mass star to reach the main sequence after
it begins to form is about
(a) a few days
(b) a few years
(c) a few thousand years
(d) a few million years
(e) a few billion years
23. During the formation of a new star, contraction stops because
(a) the star ejects a planetary
nebula
(b) electron degeneracy pressure becomes
significant
(c) hydrogen fusion reactions start in the star's
core
(d) the star's temperature begins to decrease
(e) gravity is too weak
24. When the Sun began its main sequence life it was
(a) fusing helium to hydrogen in
its core
(b) much less luminous than it is now
(c) much more luminous than it is now
(d) at about the same point in the H-R diagram as
it is now
(e) at the top of the main sequence band
25. The life of a star is best described as
(a) fusing nuclear fuels in its
center in order to delay collapse
(b) steady evolution to higher density with the
star's luminosity provided by gravitational energy
(c) fusing nuclear fuels at its surface in order to
delay collapse
(d) periods of expansion alternating with periods
of hydrostatic equilibrium
(e) increasing central density and decreasing
central temperature
26. A star starts to become a red giant when
(a) the helium flash occurs
(b) carbon is ignited in its core
(c) the planetary nebula phase is over
(d) it exhausts its supply of iron fuel in its core
(e) it exhausts its supply of hydrogen fuel in its
core
27. One key difference between degenerate material and normal gases is that
when material is degenerate
(a) the density is very low
(b) nuclear reactions can occur more easily
(c) the nuclei begin to decay
(d) the pressure does not depend on temperature
(e) unspeakable practices occur
28. Which of the following statements is WRONG? As a cluster of stars ages
(a) it produces more white dwarf
stars.
(b) progressively cooler stars become the brightest
surviving main sequence stars.
(c) the hottest stars are always the brightest.
(d) stars at the faint end of the main sequence
change very little.
(e) progressively less massive stars evolve through
the giant phases.
29. The triple-alpha reaction is the
(a) conversion of hydrogen into
helium in upper main sequence stars
(b) nuclear reaction which produces radioactive
elements in supernovae
(c) nuclear reaction which produces iron in massive
stars
(d) conversion of helium into carbon in evolved
stars
(e) hangover after a party at the AAA fraternity
30. A planetary nebula is best described as
(a) a gaseous planet.
(b) a shell of gas puffed off from a dying giant
star.
(c) a region of emission line gas that is forming a
star.
(d) a round, dark cloud of dust.
(e) gas ejected by a supernova.
31. A typical white dwarf star would be the size of
(a) the tip of your pencil
(b) New Brunswick
(c) New Jersey
(d) the Earth
(e) the Sun
32. The energy radiated by a white dwarf star comes from
(a) its decreasing store of thermal
energy
(b) degeneracy pressure
(c) nuclear fusion reactions
(d) carbon burning
(e) the energizer rabbit
33. You observe the two components of a binary star through a telescope. One
star appears red and the other blue. The red star appears brighter than the
blue star. You can conclude
(a) the red star is hotter than the
blue star
(b) the red star is less luminous than the blue
star
(c) one of the two stars is not on the main
sequence
(d) the blue star has a larger radius than the red
star
(e) nothing