Astronomy 122
Test
1
NAME
_____________________________________________________________________
Multiple Choice Questions -- 30 questions @ 2 points per question
----> 60 points
Select the best answer for each question.
1. The Solar Constant is roughly 1,400 Watts
per square meter.
of the sphere.
a. 1/5-th as large
*b. 1/25-th as large
c. 1/125-th as large
d. 1/625-th as large
e. it is the same size at Jupiter as it is at the Earth.
2. Gamma Rays _____ .
a. are a form of energy
b. have the ability to do work
c. are a type
of electromagnetic radiation
d. are able to move though a vacuum; they
don't need a medium
*e. All of the above statements about gamma rays are
true.
3. Of the following parts of the electromagnetic spectrum, which pass
freely through the atmosphere of the Earth?
a. x-rays and optical
b. radio and ultraviolet
*c. radio and optical
d. ultraviolet and optical
e. infrared and gamma-rays
4. A Main Sequence star has luminosity class _____ .
a. I
b. II
c. III
d. IV
*e. V
5. Two stars have the same surface temperature. The larger one has a
surface area 2 times
greater than the smaller one. The larger star radiates how much more energy than does
the smaller one?
*a. 2 times as much
b. 4 times as much
c. 8 times as much
d. 16 times as much
e. 64 times as much
6. Astronomers know that iron atoms are present in the Sun because _____ .
a. astronomers have analyzed samples retrieved from the Sun in
laboratories on the Earth
b. much of the Earth is iron so that, by
inference, the Sun must also contain large amounts of iron
c. the Sun is
more massive than the Earth and so must contain more massive elements like
iron
(d. dark lines whose wavelength match those of iron are
observed in the
Solar spectrum
e. the Sun has a faint reddish color suggestive of
rust
7. An atom is held together (bound) by ____ .
a. the gravitational force
b. the nuclear force
*c. the electrical
force
d. a combination of the electrical and greavitational forces
e. a
mysterious force unknown to modern science
8. X-rays are _____ than radio waves, _____ radio waves.
a. more energetic -- and travel more quickly in vacuum than
*b. more
energetic -- but travel at the same speed in vacuum as
c. more energetic --
but, strangely, travel more slowly in vacuum than
d. less energetic -- but
travel more quickly in vacuum than
e. less energetic -- and travel more
slowly in vacuum than
9. The change in the appearance of stellar spectra as you move through the
spectral sequence is due to _____ .
*a. a decrease in surface temperature from O to M stars
b. an increase
in surface temperature from O to M stars
c. a decrease in the hydrogen
content from O to M stars
d. an increase in the hydrogen content from O to
M stars
e. the varying ages of the stars
10. The Sun currently shines because _____ .
a. it generates energy through fossil fuel burning
b. it is very hot; the Sun currently does not generate energy
*c. it has a large nuclear reactor in its core where fusion of hydrogen to helium occurs
d. of the utilization of the Solar Wind power
11. The luminosity of the Sun _____ the Solar Activity Cycle.
*a. changes by less than 1 % over
b. doubles in size over
c. is 10
times larger around the maximum of
d. drops to 0 around the minimum of
12. The Russell-Vogt Theorem states that the properties of a star are
determined primarily by the star's _____ .
a. luminosity and radius
b. mass and luminosity
c. mass, chemical
composition, and radius
d. radius and chemical composition
*e. mass and
chemical composition
13. The primary difference(s) between the spectra of stars in different spectral classes
is(are) _____ .
a. the presence of a continuous component in the spectrum of some
stars
*b. the differing strengths and patterns of the absorption lines in
the spectra
c. the differing strengths and patterns of emission lines in
the spectra
d. caused by the different number of Sunspots exhibited by
different stars
e. the lack of absorption lines in the spectra of cool
stars
14. The fundamental difference between radio waves and x-rays is that _____ .
a. you can listen to radio waves
b. radio waves and x-rays always come
from different sources
c. radio waves are wave-like while x-rays are
particle-like
d. they travel at different speeds in a vacuum
*e. they
have different wavelengths
15. When the Universe began expanding 13.7 billion years
ago, it was made primarily of _______ .
a. nitrogen and oxygen
b. silicon (sand)
*c. hydrogen and helium
d. carbon and water
e. carbon, nitrogen, and oxygen
16. The rotation period for the Sun is roughly _____ .
a. 24 hours
b. 1 week
*c. 1 month
d. 1 year
e. 11 years
17. By the word spectrum, we mean _______ .
*a. the spreading of light into its component colors
b. the relation between the frequency and wavelength of electromagnetic radiation
c. the relation between the frequency and energy of electromagnetic radiation
d. a and b only
e. a, b, and c
18. The masses of stars on the Main Sequence _____ .
*a. increase from the lower right to the upper left
b. decrease from the lower right to the upper left
c. are all the same
d. have random values along the Main Sequence
e. depend strongly on the age of the star
19. The regions in the Hertzsprung-Russell diagram where there are
concentrations of stars are _____ .
a. regions in the Galaxy where stars tend to congregate
*b. are long-lived stable phases in the evolution of stars
c. where stars have used up their nuclear fuels and are collapsing
d. known as globular clusters
20. The colors of some glowing bodies are listed below. Which body is the coolest?
*a. red
b. blue
c. yellow
d. green
e. purple
21. The most numerous stars in our galaxy are ________ .
a. normal giants with large mass
b. super-giants with large mass
c. normal giants with small mass
d. Main Sequence stars with high mass
*e. Main Sequence stars with low luminosity
22. The determination of stellar parallax is important because it allows
the direct determination of _____ .
a. the masses of stars
b. the surface temperatures of stars
c. the orbital periods of binary stars
*d. the distances to stars
e. the chemical composition of stars
23. The nucleus of an atom is composed of _____ .
a. neutrons
b. protons
c. electrons
*d. a and b only
e. a, b, and c
24. Binary star systems are particularly important for _____ .
*a. the determination of the masses of stars
b. the determination of the distances to stars
c. the determination of the speeds with which stars move
d. the determination of the luminosities of stars
e. the determination of the surface temperatures of stars
25. The spectral class which shows the strongest hydrogen lines is _____ .
26. The mass-luminosity relationship for main sequence stars says _____ .
a. high mass, low luminosity
*b. high mass, high luminosity
c. low mass, high luminosity
d. that there is no systematic relationship between mass and luminosity
27. The experiments designed to detect Solar neutrinos find that _____ .
a. the number of neutrinos detected from the Sun is greater than predicted by theory
*b. the number of neutrinos detected from the Sun is right on what is predicted by theory
c. the number of neutrinos detected from the Sun is less than what is predicted by theory
d. the number of neutrinos detected from the Sun oscillates; sometimes it is more than
predicted by theory and sometimes it is less than predicted by theory
28. Early workers in spectroscopy discovered which very significant fact
about the spectra produced by hot low-density gases?
a. all hot gases produce a continuous spectrum with no
observable lines or features
*b. each chemical element in the gas produces its own
characteristic set of lines
c. all chemical elements produce the same sets of lines; their spectra are
indistinguishable in appearance
d. chemical elements emit spectral lines which move
continuously toward the blue end of the spectrum
as the gas temperature increases
29. The spectral type of the Sun is _____ .
a. O6
b. A2
c. F8
*d. G2
e. S2
30. The most useful probe of the current state of the interior of the Sun _____ .
a. is the Solar Wind, i.e., the high-speed stream of protons emitted by the Sun
*b. are the neutrinos from the Sun
c. is the radiation (the photons) we receive from the Sun
d. is the Solar Activity Cycle
e. are precise measurements of the
Solar Constant
Short Answer Questions -- 8 questions @ 5 points per question
----> 40 points
1. What is the Maunder Minimum? Explain how it shows that the
climate of the Earth is strongly affected by the behavior of the Sun.
2. The line, We are
stardust from Woodstock by Joni Mitchell, is an apt and
scientifically appropriate statement about the chemical make-up of the Earth and
us. Explain why the line is a scientifically accurate statement about the chemical
make-up of the Earth and us.
3. M type stars do not show strong hydrogren lines in the visible light portion
of their spectra. Is this
true because M stars do not contain hydrogen? If this is not true (M stars do in
fact contain hydrogen), explain why M stars do not show strong hydrogen lines in
their spectra.
4. What is Wien's Law? What is the Stefan-Boltzmann Law? To what kind of object do the Wien Law and
Stefan-Boltzmann Law apply, strictly speaking?
5. Briefly, describe how astronomers
determine the surface temperatures of stars using their continuous
spectra OR their absorption line spectra. Note--just choose one method to describe.
6. State Kirchhoff's Three Laws of Spectral Formation. Which of the
three laws applies to the formation of the absorption line spectrum
observed from most stars?
7. Sketch a Hertzsprung-Russell (H-R)
diagram. Be sure to label the axes and indicate the locations of the
Super-giants, normal giants, Main Sequence stars, and white dwarfs.
Circle the region in the H-R
diagram where the bulk of the observable stars are found.
8. Use the energy level diagram for hydrogen to answer the following questions.
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i. Which transitions reprensent lines that would fall in the visible part of the spectrum?
ii. Which transitions are Lyman transitions?
iii. Which transition has the smallest energy?
iv. Which transition represents ionization?
v. Draw in an absorption line from the Paschen series of lines.
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Part | Points |
Multiple Choice | |
Short Answer | |
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