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NAME _______________
Astronomy 1001/1005, Midterm #2 – June 22, 2007
Lab Section # ____________
Karl A. Isensee, Summer 2007
Read Instructions Carefully:
1. Mark the answers you choose on this test as it is your only opportunity to
check which answers you got right or wrong. This will not be done for you at a
later time in the departmental office. If you feel that there is a mistake on the
exam, please see Karl Isensee in Physics 475B. You are allowed to bring in one
8.5” x 11” page of notes covered on both sides to the exam
2. Print your name and section # on your answer sheet where appropriate.
3. Use a pencil, make your marks dark and neat, and erase thoroughly
4. There is only one correct answer to each question. Choose the best answer.
5. You may use this test sheet for scratch paper
1) If a small weather satellite and the large International Space Station are orbiting
Earth at the same altitude above Earth’s surface, which of the following is true?
A) The large space station has a longer orbital period
B) The small weather satellite has a longer orbital period
C) They have the same orbital period
D) You can’t say anything about their orbital periods with the information
given
2) Consider two stars (Star X and Star Y). If Star X is 3 parsecs away and Star Y is
5 parsecs away, which has the greater parallax angle?
A) Star X
B) Star Y
C) The same parallax angle
D) Cannot tell from the information given
3) Absolute magnitude is defined as the apparent magnitude a star would have if you
were observing it from a distance of 10 parsecs. Which of the following stars is
closest to us?
A) Star A (Absolute Magnitude = 1.0, Apparent Magnitude = 0.0)
B) Star B (Absolute Magnitude = 2.5, Apparent Magnitude = 2.5)
C) Star C (Absolute Magnitude = 3.0, Apparent Magnitude = 4.5)
D) Star D (Absolute Magnitude = -1.0, Apparent Magnitude = 0.0)
4) Star G has an apparent magnitude of +5.0 and an absolute magnitude of +4.0.
Star H has an apparent magnitude of +4.0 and an absolute magnitude of +4.0.
Which star will appear brighter in the night sky?
A) Star G
B) Star H
C) They will appear to be the same brightness
D) Cannot tell from the information given
5) Capella is at a distance of 14 parsecs and has an apparent magnitude of +0.05.
Which of the following could reasonably be Capella’s absolute magnitude?
A) +4.05
B) –10.5
C) –0.7
D) +0.85
6) Rigel is about 100,000 times as luminous as the Sun and belongs to the spectral
class B8. Sirius B is about 1/3000 times as luminous as the Sun and belongs to
spectral class B8. Which star has the greater surface temperature?
A) Rigel
B) Sirius B
C) They have the same surface temperature
D) Cannot tell from the information given
7) The most important property in determining the eventual fate of a star is:
A) The details of its chemical composition
B) The initial concentration of iron in its core
C) Its distance from the center of the galaxy
D) Its mass
8) The eventual fate of a low mass star like our Sun is to become a:
A) Neutron star
B) Black hole
C) Brown Dwarf
D) White Dwarf
9) Which of the following does NOT tell us something about the way in which our
solar system must have evolved?
A) The planets all orbit in about the same plane
B) The Sun spins in the same sense that the planets orbit
C) The planets’ orbits are nearly circular
D) The planets further from the Sun take longer to complete their orbits
10) Which of the following would make you weigh half as much as you do right now?
A) Take away half of the Earth’s atmosphere
B) Double the distance from the Earth to the Sun
C) Take away half of the Earth’s mass
D) More than one of the above are correct answers
11) Global warming is thought to be caused by:
A) The destruction of the ozone layer
B) The trapping of heat by nitrogen in the atmosphere
C) The addition of gasses like Carbon Dioxide into the atmosphere
D) The degradation of Earth’s magnetic field
12) If you were to double the mass of Jupiter, what would happen?
A) Its radius would substantially increase
B) Since it is made up of the same material as the Sun, it would begin nuclear
fusion and become a star
C) It composition would change from primarily hydrogen and helium to
primarily methane and ammonia
D) Its density would increase but its radius would remain roughly
constant
13) Correctly order the layers of Jupiter from the center of the planet outwards:
A) Core, metallic hydrogen, liquid hydrogen, gaseous hydrogen, cloud
tops
B) Core, liquid hydrogen, gaseous hydrogen, cloud tops
C) Core, liquid hydrogen, metallic hydrogen, gaseous hydrogen, cloud tops
D) Metallic hydrogen, liquid hydrogen, gaseous hydrogen, cloud tops
14) One of Jupiter’s moons has a surface consisting completely of frozen water.
Many scientists believe that there is an ocean of liquid water underneath the
surface and thus a good chance of life. What moon of Jupiter is this?
A) Ganymede
B) Callisto
C) Titan
D) Europa
15) Why is Io volcanically active?
A) It formed late in the history of the solar system, so it still contains
substantial internal energy
B) It is close enough to Jupiter so that the heat from Jupiter provides it with a
substantial energy source
C) The tidal forces from Jupiter stretch the planet, tidally heating the
interior
D) None of the above
16) Why are Neptune and Uranus blue-green while Jupiter and Saturn are not?
A) The upper layers of Neptune and Uranus are made out of different
gasses
B) Neptune and Uranus are further from the Sun, so they receive less
sunlight, so they appear to be dimmer colors
C) Neptune and Uranus are substantially cooler, so they appear to be a
different color due to the temperature difference
D) The magnetic fields on Neptune and Uranus substantially dim the colors in
an analogous situation to how dark sunspots are created by magnetic fields
on the Sun
17) Which of the following is a true statement about the mass and composition of the
asteroid belt?
A) Asteroid are very small on average, but there are so many of them that the
mass of the asteroid belt is much greater than the mass of Earth
B) Asteroids are so small that even added together, they are much less
massive than Earth
C) Asteroids are relatively large on average, and there are so many of them
that the asteroid belt is much more massive than any planet but Jupiter
D) Astronomers have too little information to accurately estimate the mass of
the asteroid belt
18) What information do meteorites frequently give astronomers?
A) They can tell us about past temperature fluctuations of the Sun
B) They can give use information about the current strength of the solar wind
C) They can give us information about the past strength of the solar wind
D) They can give us information about the initial composition of the solar
system
19) Which of the following statements about comets is always true?
A) Comets have tails
B) Comets formed beyond the orbit of Mars
C) Comets pass close to the Sun at least every few thousand years
D) More than one of the above answers are correct
20) What discovery was a major reason for the demotion of Pluto from a planet to a
dwarf planet?
A) The discovery of the Kuiper Belt
B) The discovery of the Oort Cloud
C) The discovery of the large asteroid Ceres
D) The discovery of the large Kuiper Belt Object Eris
21) What evidence do we have that Earth has been hit by a comets and/or asteroids in
the past?
A) Impact craters like the Chicxulub crater
B) At least one layer of iridium in the geological record
C) Evidence of a massive atmospheric explosion in Siberia in the early 20th
Century
D) All of the above
22) Which of the following are the two laws or axioms of special relativity?
A) Time dilates and the speed of light is a constant in all reference frames
B) There is no such thing as simultaneity and the laws of physics are the same
for everybody
C) The speed of light is constant in all reference frames and the laws of
physics are the same for everybody
D) The speed of light is relative based on what reference frame you are in and
the laws of physics are the same for everybody
23) Jose and Beth are in two spaceships in deep space far away from any other
objects. Beth believes that she is at rest and that Jose is moving toward her at
99.9% of the speed of light. Jose believes that he is at rest and that Beth is
moving toward him at 99.9% of the speed of light. Jose then shines a flashlight at
Beth. Which of the following is true?
A) Beth sees the light moving towards her at the speed of light, but Jose sees
the light moving away from him at a much slower speed
B) Jose sees the light moving away from him at the speed of light, but Beth
sees the light approaching her at a much greater speed.
C) Jose sees the light moving away from him at a much lesser speed than the
speed of light, and Beth sees the light moving towards her at a much
greater speed than the speed of light
D) Jose sees the light moving away from him at the speed of light, and
Beth sees the light moving toward her at the speed of light
24) Einstein’s Equivalence Principle states that the force due to gravity is equivalent
to:
A) Moving at a constant speed
B) Accelerating at a constant rate
C) Constantly changing one’s acceleration
D) None of the above
25) Beijing and Philadelphia are both at a latitude of 40 degrees North. What is the
quickest path between the two cities in an airplane?
A) Follow the 40N latitude line
B) Follow the great circle north, passing over Russia and Canada
C) Follow the great circle south, eventually passing over the equator
D) Simply take off and remain stationary with respect to the Sun, and let the
Earth rotate beneath you until Philadelphia is directly below.
26) Which of the following is a fundamental particle?
A) Neutron
B) Proton
C) Electron
D) Hydrogen atom
27) You are now the size of a proton and have been placed inside of a helium nucleus.
Correctly order the strength of the four fundamental forces that you feel from the
strongest force to the weakest.
A) Gravity, Electromagnetic, Strong Nuclear Force, Weak Nuclear Force
B) Electromagnetic, Gravity, Strong Nuclear Force, Weak Nuclear Force
C) Strong Nuclear Force, Electromagnetic, Weak Nuclear Force, Gravity
D) Strong Nuclear Force, Weak Nuclear Force, Gravity, Electromagnetic
28) You send an electron towards two slits in an otherwise solid wall. If you don’t
place a detector at the slits, the electron creates an interference pattern after it
passes through the slits. If you do place detectors at the slits, the electron passes
through one slit or the other and does not create an interference pattern. This is an
illustration of what important quantum mechanical property?
A) The Heisenberg Uncertainty Principle
B) Quantum Tunneling
C) The Exclusion Principle
D) Wave-Particle Duality
29) The Sun and all stable stars are in gravitational (also known as hydrostatic)
equilibrium. What two forces are precisely balanced when an object is in this
type of equilibrium?
A) Gravity and the Electromagnetic force
B) Gravity and some kind of pressure
C) Electromagnetic and the Centrifugal Force
D) Gravity and Angular Momentum
30) Correctly order the layers of the Sun, from the center outwards.
A) Core, Radiation Zone, Convection Zone, Photosphere, Chromosphere,
Corona
B) Core, Convection Zone, Photosphere, Radiation Zone, Chromosphere,
Corona
C) Core, Radiation Zone, Convection Zone, Chromosphere, Corona,
Photosphere
D) Core, Convection Zone, Radiation Zone, Chromosphere, Corona,
Photosphere
31) What primarily determines the color that a star appears to be?
A) The mass of the star
B) The temperature of the core of the star
C) The temperature of the surface of the star
D) The luminosity of the star
32) Stars like the Sun do nuclear fusion via the proton-proton chain. What are the
beginning particles and ending products of the proton-proton chain?
A) The proton-proton chain turns 2 hydrogen nuclei into 1 helium nucleus
B) The proton-proton chain turns 1 helium nucleus into 2 hydrogen nuclei
C) The proton-proton chain turns 4 hydrogen nuclei into 1 helium
nucleus
D) The proton-proton chain turns 1 helium nucleus into 4 hydrogen nuclei
33) Why do sunspots appear to be dark?
A) They are so hot that they emit all of their light at energies that the human
eye cannot see
B) The atmosphere of the Sun is too thick for light to make it through at the
location of the sunspot
C) They are holes in the Sun, so you are seeing into the darker depths of the
Sun
D) The temperature is slightly lower in those locations, making the
sunspot appear dark against the hotter areas of the surface of the Sun
34) When the Sun leaves the main sequence and enters the Red Giant Branch, which
of its properties will change the most?
A) Its mass will dramatically increase
B) Its mass will dramatically decrease
C) Its radius will dramatically increase
D) Its temperature will dramatically decrease (by at least a factor of 5)
35) Why do stars usually form in clusters?
A) It is unlikely that a smaller star forming cloud would reach the
densities necessary to form a single star
B) Star forming clouds that would form a single star are usually too cold to
form a star
C) Star forming clouds that would form a single star are usually too hot to
form a star
D) The only clouds in the Interstellar Medium are too large to form a single
star and must fragment into many smaller stars
36) What is the primary energy source for a protostar?
A) Hydrogen fusion
B) Helium fusion
C) Fission
D) Gravitational contraction
37) What is a brown dwarf?
A) The smallest type of star on the main sequence
B) An object that is larger than a planet and made out of star like
material, but didn’t have enough mass to begin nuclear fusion
C) A kind of protostar
D) A first generation star
38) You have two incandescent lightbulbs that act as perfect blackbodies. Lightbulb
A is at a much higher temperature than Lightbulb B, but is otherwise identical.
Which of the following statements is true?
A) Lightbulb A emits much more energy than Lightbulb B
B) Lightbulb A emits higher energy (shorter wavelength) radiation on
average than Lightbulb B
C) Both objects have continuous spectra
D) All of the above
39) You are looking at an incandescent lightbulb that acts as a perfect blackbody
through a dense cloud of gas. What general type of spectrum would you expect to
observe?
A) Emission Spectrum
B) Absorption Spectrum
C) Continuous Spectrum
D) It depends on what type of gas you are looking through
40) Why doesn’t the Sun use the CNO cycle to produce energy?
A) Its core isn’t hot enough to begin the CNO cycle
B) It will, but only after it leaves the main sequence
C) Its magnetic field isn’t strong enough to begin the CNO cycle
D) There is no Carbon, Nitrogen, or Oxygen present in the Sun