PRACTICE EXAM
4 on Galaxies
1. The general shape of our galaxy is
nearest to that of a(n)
a. pear.
b. egg.
c. ball.
d. fried
egg.
2. The distance of the Sun from the center
of the Galaxy is
nearest to __________ parsec(s) or
__________ light years.
a. 1;
3.26
b. 100;
326
c. 1,000;
3,260
d. 10,000;
32,600
e. 30,000;
100,000
3. Which of the following objects or
techniques is most useful to
determine the distance to the most
distant objects in the Galaxy?
a. solar-type
stars
b. Cepheid
variables
c. RR Lyrae variables
d. main
sequence
fitting methods
e. white
dwarf stars
4. The period of revolution of the Sun about
the galactic center is closest to
a. 3
million years.
b. 25
million years.
c. 250
million years.
d. 2
billion years.
e. 25
billion years.
5.
Spiral arms appear to be prominent in spiral galaxies because
a. all
the stars are
distributed in a spiral pattern.
b. cool
stars are
distributed in a spiral pattern while the
hot stars are spread more uniformly.
c. hot
stars are
distributed in a spiral pattern while the
cool stars are spread more uniformly.
d. globular
clusters
are distributed in a spiral pattern
around the Galaxy.
6. Our ability to detect distant stars in
our galaxy is limited because of
a. absorption
by dust
in the Galaxy.
b. the
existence of
strong 21-cm radiation in the Galaxy.
c. the
existence of
many bright nebulae in the Galaxy.
d. none
of the above;
there is no limit in our ability to detect distant stars.
7. The primary use of observations of 21-cm
radiation is to determine
a. distances
to
distant stars.
b. the
chemical
c. the
spiral
structure of the Galaxy.
d. the
distance of
the Sun from the center of the Galaxy.
8. The
nucleus of the Galaxy is
a. hot
stars.
b. cool
stars.
c. hydrogen
gas.
d. planetary
nebulae.
e. solar-type
stars.
9. The
most massive
a. the
disk.
b. the
nucleus.
c. the
halo.
d. the
spiral arms.
10. Astronomers can usually differentiate
Population II stars near the Sun from
Population
I stars by
a. the
colors of the
stars.
b. the
amount of
interstellar reddening in each.
c. the
strength of
radio emission from each.
d. the
difference in
Doppler shift for each.
e. none
of the above;
it is not possible to differentiate these two classes of stars.
11. The density wave which is thought to
travel throughout the Galaxy is most analogous to
a. a
water wave.
b. a
sound wave.
c. a
light wave.
12. As evidenced by the concentration of gas
and dust in the
spiral arms, a density wave has its
strongest effect on
a. stars.
b. gas
and dust.
c. star
clusters.
d. binary
stars.
e. other
nearby
galaxies.
13. The observed distribution of globular
clusters indicates that
the gas cloud from which the Galaxy
formed was
a. disk-shaped.
b. spherical.
c. elliptical.
14. We know the stars observed in globular
clusters all have relatively low masses because
a. the
more massive
ones have all evolved and are "dead" stars.
b. the
high mass
stars were ejected from the clusters by tidal interactions with the
Milky Way.
c. the
high mass stars
were ejected from the cluster in collisions with the Magellanic
Clouds.
d. the
high mass
stars are too faint to observe.
e. only
low mass
stars formed in globular clusters.
15. Important differences between stars of
Pop. I and Pop. II are that
a. Pop.
II stars are
young and move slowly around the Galaxy.
b. Pop.
II stars are
metal poor and young.
c. Pop.
II stars are
metal poor stars in the galactic halo.
d. Pop.
II stars are
slowly moving stars in the galactic disc.
e. Pop.
II stars are
young, metal rich stars in the galactic nucleus.
16. An argument against the evolution of
galaxies from spiral to elliptical is the fact that
a. both
types of
galaxies show current star formation.
b. neither
type of
galaxy shows current star formation.
c. both
types of
galaxies contain equally old stars (10 billion years).
d. the
oldest stars
in elliptical galaxies are much older than the oldest stars in spiral
galaxies.
17. The Magellanic
Clouds are
a. irregular
galaxies.
b. spiral
galaxies.
c. elliptical
galaxies.
d. large
clouds of
gas and dust.
18. The distances to the nearest galaxies can
be determined using
a. spectroscopic
parallax.
b. main
sequence
fitting.
c. proper
motions.
d. RR Lyrae stars.
e. Cepheid
variables.
19.
Which of the following is NOT an example of a standard candle?
a. Cepheids
b. supergiants
c. the
brightest
galaxy in a cluster
d. supernovae
e. pulsars
20. The Tully-Fisher method for finding
distances to galaxies relates absolute magnitude and
a. redshift.
b. rotational
velocity.
c. magnetic
field.
d. angular
size.
e. apparent
magnitude.
21.
What is the easiest way of measuring the
rotation of a spiral galaxy?
a. pick
out
individual stars, and measure their Doppler shifts
b. use
21-cm emission
to measure the motion of the gas in the disk
c. look
for
supernova, and observe how they expand
d. determine
the
location and distribution of globular clusters within the galaxy
22.
Which type of galaxies, have a wider range
of luminosities and sizes?
a. Ellipticals
b. Spirals
c. SO
23.
Galaxies in clusters
a. tend
to move
randomly within the cluster, and eventually will leave the cluster.
b. do
not orbit, but
are fixed in space.
c. orbit
about the
center of the cluster.
d. often
merge in the
center to form a giant spiral galaxy.
24.
The most numerous galaxies in the Local
Group are _______ galaxies.
a. elliptical
b. spiral
c. irregular
25.
Most of the galaxies in rich clusters are
a. normal
spirals.
b. barred
spirals.
c. elliptical.
d. irregular.
e. divided
equally
among all types.
26.
The X rays
observed to
a. a
black hole in
the cluster center.
b. mass
transfer onto
neutron galaxies.
c. highly
energetic
collisions of galaxies.
d. a hot
intergalactic medium.
e. hot
galactic
halos.
27.
Spectra of distant galaxies show
a. a
large red shift.
b. a
large blue
shift.
c. no
spectral shift.
d. a
small red shift.
e. a
small blue
shift.
28.
The Hubble law may be expressed
mathematically as
a. v = Hd.
b. v =
H/d.
c. v =
Hd2.
d. v =
H/d2.
e. a
very
29.
The Hubble constant is related to the
__________ of the universe.
a. size
b. mass
c. age
d. luminosity
30.
The fact that jets are NOT observed in all
radio galaxies
a. proves
that there
is not a black hole at their core.
b. proves
that there
is a black hole at their core.
c. indicates
that our
orientation to the galaxy may prevent us from seeing them.
d. the
question is incorrect,
jets are seen around all radio galaxies.
31.
The radio emission in a typical radio
galaxy is produced by _______ emission.
a. thermal
b. synchrotron
c. black
hole
d. cyclotron
e. thermonuclear
32.
Seyfert galaxies
are characterized by
a. small
reddish
nuclei.
b. large
reddish
nuclei.
c. large
bluish
nuclei.
d. small
bluish
nuclei.
33.
The broad spectral lines formed in Seyfert
galaxy nuclei are indicative of
a. rapid
motion by
the galaxy away from the observer.
b. rapid
motion by
the galaxy towards the observer.
c. the
presence of
magnetic fields.
d. large
turbulent
velocities in the nucleus.
e. a
degenerate
nucleus.
34.
The most
conspicuous observed property of quasars is their
a. low
apparent
magnitude (high apparent brightness).
b. high redshift.
c. high blueshift.
d. dramatic
appearance on photographs.
e. strong spiral structure.
35.
The radio emission from quasars shows
characteristics of
a. thermal
emission
from a hot body.
b. thermal
emission
from a cool body.
c. nonthermal
synchrotron emission.
d. thermal
synchrotron emission.
36.
The active region of a quasar whose light
output varies considerably in a month is
a. a
light-month in
size.
b. a
light-year in
size.
c.
a parsec in size.
d. the
size of the
Milky Way.
e. unknown
in size.
37.
Which of the following properties is NOT
present in both quasars and Seyfert galaxy
nuclei?
a.
b. blue
color
c. 10 %
of them are
radio sources
d. variability
of
light
e. similar
emission
spectra
Answer Key
for Practice Exam 3 on Galaxies
1. d
2. d
3. b
4. c
5. c
6. a
7. c
8. b
9. c
10. d
11. b
12. b
13. b
14. a
15. c
16. c
17. a
18. e
19. e
20. b
21. b
22. a
23. c
24. a
25. c
26. d
27. a
28. a
29. c
30. c
31. b
32. d
33. d
34. b
35. c
36. a
37. a