Name: 
 

Final Practice Test


Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
 

1. 
Which of the following is not a characteristic of the stars of the disk component of our galaxy?
a.
circular orbits
b.
randomly inclined orbits
c.
higher metal abundance
d.
young stars
e.
star formation regions
 

2. 
Younger stars have more heavy elements because
a.
old stars destroy heavy elements as they age.
b.
young stars burn their nuclear fuels faster.
c.
the heavy elements were made in previous generations of stars.
d.
heavy elements haven't had time to settle to the core of these younger stars.
e.
all of these
 

3. 
The first stars to form in our galaxy
a.
had circular orbits.
b.
had highly elliptical orbits.
c.
were population I stars.
d.
all had orbits in the same plane.
e.
formed the galactic clusters we see today.
 

4. 
Good spiral tracers are all

I.
very old.
II.
very young.
III.
very luminous.
IV.
moving with large radial velocities.
a.
I & III
b.
I & IV
c.
II & III
d.
II & IV
e.
I, III, & IV
 

5. 
Radio maps of our galaxy show spiral arms because
a.
the arms have larger Doppler shifts.
b.
the gas in the spiral arms is very hot.
c.
the dust in spiral arms is denser.
d.
the gas in spiral arms is denser.
e.
the stars in the spiral arms emit most of their energy at radio wavelengths.
 

6. 
Population II stars

I.
are primarily found in the disk of the galaxy.
II.
contain more heavy metals than population I stars.
III.
are primarily old low mass stars.
IV.
are located in globular clusters.
a.
III & IV
b.
I & II
c.
II
d.
IV
e.
I, II, & III
 

7. 
The chemical abundance of population I stars
a.
indicates that they were formed before the population II stars.
b.
indicates that the material they formed from had been enriched with material from supernovae.
c.
indicates that they contain very few heavy metals compared to halo stars.
d.
depends on the temperature of the star.
e.
depends on the mass of the star.
 

8. 
The center of our galaxy lies in the direction of the constellation of
a.
Ursa Minor.
b.
Ursa Major.
c.
Sagittarius.
d.
Orion.
e.
Monoceros.
 

9. 
The nuclear bulge of our galaxy
a.
contains stars that are primarily population I stars.
b.
contains relatively large amounts of gas and dust.
c.
contains stars primarily associated with the spherical component of our galaxy.
d.
contains stars primarily associated with the disk component of our galaxy.
e.
a, b and d
 

10. 
The orbits of population I stars

I.
are confined to disk of the galaxy.
II.
are very elliptical.
III.
are nearly circular.
IV.
are randomly inclined to the disk of the galaxy.
a.
I
b.
IV
c.
I & IV
d.
II & IV
e.
I & III
 

11. 
Radio maps of the spiral arms of our galaxy
a.
reveal that our galaxy is a grand design spiral.
b.
map the location of Hot O and B stars by the radio radiation they emit.
c.
reveal that the spiral arms are winding up and growing closer together.
d.
reveal that the sun is currently located in the center of a spiral arm.
e.
map the location of dense neutral hydrogen clouds.
 

12. 
Sgr A* is believed to be the center of the Milky Way galaxy because

I.
It lies in the general direction of the center of the galaxy based on observations of globular clusters.
II.
It is located near the galactic corona.
III.
It is easily visible with optical telescopes and has the appearance of a massive black hole.
IV.
It does not move with respect to the rest of the galaxy.
a.
I & II
b.
II & III
c.
I & IV
d.
II & IV
e.
I, III, & IV
 

13. 
A Type I Cepheid has been located in an open cluster. The period of the Cepheid variable is 30 days and the variables apparent visual magnitude is 10. What is the distance to this open cluster?

studyguide12-20_files/i0140000.jpg
a.
100 pc
b.
10,000 pc
c.
20 pc
d.
300 pc
e.
2500 pc
 

14. 
An E galaxy contains
a.
mostly lower-main sequence stars and giants.
b.
mostly upper main sequence stars and giants.
c.
mostly upper main sequence stars and gas and dust.
d.
roughly equal numbers of upper and lower main sequence stars.
e.
mostly white dwarfs and supergiants.
 

15. 
An irregular galaxy contains
a.
mostly lower-main sequence stars and giants.
b.
mostly upper main sequence stars and giants.
c.
mostly upper main sequence stars and gas and dust.
d.
mostly upper and lower main sequence stars and gas and dust.
e.
mostly white dwarfs and supergiants.
 

16. 
The look-back time is
a.
how long the light from an object takes to reach Earth.
b.
numerically equal to the distance in light-years.
c.
smaller for more distant objects.
d.
all of the above
e.
a and b above
 

17. 
Astronomers now speculate that a galaxy's shape depends on all of the following except
a.
the rate of star formation.
b.
the history of past collisions.
c.
the mass.
d.
the chemical composition.
e.
All of these are important in determining a galaxy's shape.
 

18. 
We should expect galaxies to collide fairly often because
a.
they are large with respect to their separation distances.
b.
galaxies contain large amounts of neutral hydrogen.
c.
galaxies occur in clusters.
d.
a and c
e.
none of the above
 

19. 
A tuning fork diagram is shown below. Which of the labeled figures represents an SBa galaxy?

studyguide12-20_files/i0200000.jpg
a.
1
b.
2
c.
3
d.
4
e.
5
 

20. 
A tuning fork diagram is shown below. Which of the labeled figures represents an Sc galaxy?

studyguide12-20_files/i0210000.jpg
a.
1
b.
2
c.
3
d.
4
e.
5
 

21. 
A tuning fork diagram is shown below. Which of the labeled figures represents an SBc galaxy?

studyguide12-20_files/i0220000.jpg
a.
1
b.
2
c.
3
d.
4
e.
5
 

22. 
A tuning fork diagram is shown below. Which of the labeled figures represents an E0 galaxy?

studyguide12-20_files/i0230000.jpg
a.
1
b.
2
c.
3
d.
4
e.
5
 

23. 
_________ galaxies contain large clouds of gas and dust, both young and old stars, but have no obvious spiral arms or nucleus.
a.
Irregular
b.
S0
c.
E7
d.
Sa
e.
E0
 

24. 
The dark matter in galaxies has been hypothesized to be composed of
a.
neutral hydrogen clouds.
b.
red dwarfs.
c.
weakly interacting massive particles.
d.
H II regions.
e.
all of the above.
 

25. 
Observations of galaxies and clusters of galaxies indicate that about _________ per cent of the universe is dark matter.
a.
5
b.
25
c.
50
d.
75
e.
95
 

26. 
Starburst galaxies
a.
contain a large number of very young stars, but very little evidence of gas clouds.
b.
contain a large number of very old stars and almost no gas or dust.
c.
are often associated with a galaxy that is colliding with another galaxy.
d.
are common in rich clusters.
e.
are composed of filaments and voids.
 

27. 
An elliptical galaxy could
a.
evolve into an irregular galaxy when it has used up all of its gas and dust.
b.
be formed from the collision and merger of spiral galaxies.
c.
evolve from a single spiral galaxy when the spiral has used up all of its gas and dust.
d.
become a starburst galaxy if it were to move through the hot intergalactic medium of a cluster.
e.
evolve from an S0 galaxy if the S0 galaxy were to increase its rotation rate.
 

28. 
If a galaxy has a radial velocity of 8000 km/sec and the Hubble constant is 70 km/sec/Mpc, what is the distance to this galaxy?
a.
8.75 x 103 Mpc
b.
2.4 x 109 Mpc
c.
5.6 x 105 Mpc
d.
114 Mpc
e.
8.75 x 10-3 Mpc
 

29. 
If the absolute magnitude of a supernova is -19 and a galaxy is found that contains a supernova with an apparent magnitude of 16, what is the distance to the galaxy?
a.
100 AU
b.
100 pc
c.
100 ly
d.
100 kpc
e.
100 Mpc
 

30. 
The radio lobes that flank some radio galaxies produce mainly
a.
21-cm radiation.
b.
synchrotron radiation.
c.
black body radiation.
d.
emission lies due to hydrogen.
e.
absorption lines due to hydrogen.
 

31. 
Centaurus A is a radio galaxy that has a galaxy at the center. This central galaxy of Centaurus A contains an elliptical galaxy encircled by a ring of dust. The elliptical galaxy rotates about an axis that is in the plane of the dust ring. The dust ring rotates about an axis that is perpendicular to the axis of rotation of the elliptical galaxy. What does this suggest about this central galaxy of Centaurus A?
a.
The radio jets have caused the dust disk to be driven around the elliptical galaxy.
b.
There are at least two black holes at the center of the elliptical galaxy.
c.
Centaurus A is probably the result of a merger of an elliptical galaxy and a spiral galaxy.
d.
Dust is produced as the jets interact with the intergalactic medium.
e.
Elliptical galaxies often contain dust that forms a disk along their rotation axis.
 

32. 
If the red shifts of quasars arise from the expansion of the universe,
a.
a quasar must be very small.
b.
a quasar must be within the Local Group.
c.
a quasar must be single star with an extremely large mass.
d.
a quasar must be moving toward Earth with a large radial velocity.
e.
a quasar must be very luminous.
 

33. 
We suspect that quasars are the active centers of galaxies because
a.
quasar fuzz produces stellar spectra.
b.
a few quasars have large red shifts.
c.
some quasars fluctuate rapidly.
d.
all of the above.
e.
none of the above
 

34. 
The discovery of the gravitational lens effect for quasars
a.
shows that quasars were located within the local group of galaxies.
b.
shows that quasars were giant elliptical galaxies at very great distances.
c.
shows that quasars are much further away than the distant galaxy that forms the gravitational lens.
d.
proves Newton's theory of gravitation by showing that the photon was affected by gravity.
e.
proves the existence of super massive black holes at the center of active galactic nuclei.
 

35. 
Statistical evidence
a.
can be used to draw conclusions about a specific cases.
b.
is applicable to classes of objects where only a few objects from the class have been studied.
c.
allows scientists to determine the mechanism that produces the dust ring in Centaurus A.
d.
allows scientists to deduce general characteristics about a class of objects with similar properties.
e.
provides insight into the behavior of an individual object based on careful observations of it.
 

36. 
Evidence that supports quasars being the nuclei of very distant galaxies includes
a.
the existence of quasar fuzz.
b.
the observation of a supernova near a quasar and at the same distance.
c.
gravitational lensing of some quasars by nearby galaxies.
d.
all of the above
e.
none of the above
 

37. 
A BL Lac object is the same as a
a.
Type 1 Seyfert.
b.
Type 2 Seyfert.
c.
double-lobed radio galaxy.
d.
blazar.
e.
quasar.
 

38. 
_________ is (are) observed when light from a distant quasar travels past a massive galaxy between us and the quasar, and this light is focused to form two or more images of the same quasar.
a.
A double-lobed radio galaxy
b.
Superluminal expansion
c.
The gravitational lens effect
d.
A blazar
e.
Gravitational waves
 

39. 
Seyfert galaxies
a.
are more common in close pairs of galaxies than in isolated systems.
b.
emit more energy at x-ray, ultraviolet, infrared, or radio wavelengths than normal spiral galaxies.
c.
generally show red shifts greater than 1.
d.
a and b
e.
a, b and c
 

40. 
The assumption of universality states that
a.
the universe looks the same at all epochs.
b.
the universe looks the same from all locations over sufficiently great distances.
c.
the universe looks the same in all directions over sufficiently great distances.
d.
the physical laws we observe on Earth apply everywhere in the universe.
e.
all of the above
 

41. 
The assumption of isotropy states that
a.
the universe looks the same at all epochs.
b.
the universe looks the same from all locations over sufficiently great distances.
c.
the universe looks the same in all directions over sufficiently great distances.
d.
all of the above
e.
none of the above.
 

42. 
The assumption of homogeneity states that
a.
the universe looks the same at all epochs.
b.
the universe looks the same from all locations over sufficiently great distances.
c.
the universe looks the same in all directions over sufficiently great distances.
d.
all of the above
e.
none of the above.
 

43. 
During the first moments of the big bang, nuclear fusion reactions made few heavy elements because
a.
all heavy nuclei are unstable.
b.
no stable nuclei exist with masses of 5 or 8 hydrogen masses.
c.
the helium nucleus is unstable.
d.
the temperature and density were too low.
e.
no nuclei heavier than helium could form since there weren't any electrons formed.
 

44. 
If galaxy A is four times more distant than galaxy B, then according to the Hubble Law, galaxy A will recede ___________ than galaxy B.
a.
16 times faster
b.
4 times faster
c.
2 times faster
d.
1.2 times faster
e.
0.25 times faster
 

45. 
The universe is said to be closed if

I.
gravity is strong enough to stop the expansion in a finite time.
II.
the density of the universe is less than the critical density.
III.
the universe is finite.
a.
I & II
b.
I & III
c.
II & III
d.
I, I, & III
e.
none of the above
 

46. 
If the universe is closed, then its age will be
a.
less than two-thirds of 1/H.
b.
more than two-thirds of 1/H.
c.
equal to 1/H
d.
equal to H squared.
e.
equal to the square-root of H.
 

47. 
If the universe is closed and finite, then
a.
the universe has a center and an edge.
b.
the universe will expand forever.
c.
the final fate of the universe will be very cold and of extremely low density.
d.
the space-time of the universe is negatively curved
e.
none of the above
 

48. 
_________ cause a sudden brightening of distant stars by gravitationally lensing the light from those stars. This processes causes the distant stars to grow brighter over a period of a few tens of days.
a.
WIMPs
b.
neutrinos
c.
globular clusters
d.
MACHOs
e.
none of the above
 

49. 
Measured ages of globular clusters and a study of the time required for massive stars to build up the present abundance of heavy elements suggests that the universe is
a.
no more than 20 billion years old.
b.
no more than 10 billion years old
c.
at least 14 billion years old
d.
flat
e.
closed
 

50. 
If the universe is flat
a.
its age will be equal to 1/H.
b.
its age will be equal two-thirds of 1/H.
c.
the density of the universe is less than the critical density.
d.
the density of the universe is greater than the critical density.
e.
dark matter accounts for a small fraction of the density of the universe.
 

51. 
The flatness problem and horizon problem
a.
are solved if there was a sudden inflation of the universe at time before recombination occurred.
b.
show that the universe cannot be described by the steady state theory.
c.
show that dark matter must be a small fraction of the total mass of the universe.
d.
imply that the universe was once much hotter than it is now.
e.
imply that the inflationary theory is incorrect.
 

52. 
Galaxy seeds around which galaxies, clusters and walls grew may have been
a.
caused by hot dark matter.
b.
caused by baryons.
c.
the result of the separation of the electromagnetic and weak forces.
d.
the result of freezing water molecules shortly after the universe became transparent to photons.
e.
caused by defects in space-time.
 

53. 
If a two dimensional universe has a negative curvature
a.
the area of a circle will be greater than ðr2.
b.
the area of a circle will be equal to ðr2.
c.
the universe is infinite.
d.
the universe is finite but bounded
e.
the universe will have a center
 

54. 
Whether the universe is open, closed or flat depends on the ________ of the universe.
a.
luminosity
b.
density
c.
temperature
d.
radius
e.
rotation rate
 

55. 
The age of the universe can be determined if
a.
the universe is flat.
b.
the amount of dark matter in the universe can be accurately determined.
c.
the rate of recession of the galaxies in the Local Group can be accurately determined.
d.
the temperature of the cosmic background radiation can be accurately determined.
e.
the Hubble constant and density of the universe can be accurately determined.
 

56. 
If a galaxy is located at a distance of 18 Mpc and it is found to have recessional velocity of 1170 km/sec, what is Hubble's constant based only on this galaxy?
a.
65 km/sec
b.
75 km/sec
c.
55 km/sec
d.
85 km/sec
e.
95 km/sec
 

57. 
The oldest rocks found on Earth are about _________ years old.
a.
10 billion
b.
5.3 billion
c.
4.6 billion
d.
3.9 billion
e.
6.2 million
 

58. 
Which of the following is not a characteristic of the terrestrial planets?
a.
low average density
b.
orbits inside the asteroids
c.
craters in old surfaces
d.
small diameters
e.
very few satellites
 

59. 
A future news release might report that a new planet has been found around a star very similar to our sun. This newly discovered planet is claimed to have a mass 40 times that of Earth and is located nearly 25 AU from the star it orbits. Which of the following would be a reasonable prediction about this planet?

I.
The planet will probably have a mean density of around 5 g/cm3.
II.
The planet will probably have a radius of around five to ten times greater than Earth's.
III.
The planet will probably have several satellites.
IV.
The planet will probably have a composition that is mostly hydrogen and helium.
a.
I & IV
b.
I, II, & III
c.
II, III, & IV
d.
I, II, & IV
e.
I, II, III, & IV
 

60. 
A(n) _________ is a solar system object that enters Earth's atmosphere and becomes very hot due to friction between the object and Earth's atmosphere.
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