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Astronomy 101, Exam #3
B
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No notes, No books; You can use calculators
Constants that you may need to know:
c = 3 x 108 m/s
1 AU = 1.49 ×1011 meters
1 light year = 9.46 × 1015 meters
h = 6.626 x 10-34 J●s
G = 6.67 × 10-11 m3 kg-1 s-2
g = 9.8 m/s2
σ = 5.67 x 10-8 W m-2 K-4
mass of Earth = 5.97 × 1024 kg
mass of Moon = 7.35 x 1022 kg
radius of Earth = 6.38 × 106 m
1 nm = 1 x 10-9 meters
mass of Sun = 1.99 x 1030 kg
mass of Jupiter = 1.90 x 1027 kg
radius of Jupiter = 7.15 × 107 m
radius of Moon = 1.74 × 106 m
1) Assume that 239U has a half-life of 23 minutes and decays into 239Np. You initially
start with 400 grams of pure 239U. How many grams of 239U will you have in 69 minutes?
A) 25 grams
B) 50 grams
C) 75 grams
D) 100 grams
E) 12.5 grams
2) You find a rock that you believe to be a meteorite. You date it using the Rb87-Sr87
dating system where Rb87 decays to Sr87. You calculate its formation age and find it to be
6.5 billion years old. Which is the unlikeliest possible explanation for this age?
A)
B)
C)
D)
E)
The rock is from another solar system.
The age of the rock was calculated incorrectly.
The rock is from the Earth
The rock lost Rb87
The rock gained Sr87
3) Assume that 40K has a half-life of 1.25 x 109 years and decays into either 40Ar or 40Ca.
You initially start with 500 grams of pure 40K. How many grams of 40K will you have in
2.5 x 109 years?
A) 50 grams
B) 100 grams
C) 125 grams
D) 250 grams
E) 500 grams
Astronomy 101, Exam #3
B
4) Which is true about P- and S-waves?
A) P-waves cannot travel through a gas while S-waves cannot travel through
liquids.
B) P-waves can travel through liquids while S-waves cannot travel through solid
material.
C) P-waves cannot travel through liquids while S-waves cannot travel through
liquids.
D) P-waves cannot travel through solid material while S-waves cannot travel
through liquids.
E) P-waves can travel through liquids while S-waves cannot travel through
liquids.
5) Who was the second man to walk on the Moon?
A)
B)
C)
D)
E)
Buzz Aldrin
Stan Love
Neil Armstrong
Tom Jones
John Glenn
6) The original crust of the Moon is called the Lunar …
A)
B)
C)
D)
E)
Maria
Highlands
Estuaries
Silles
Eclipses
7) The Earth’s magnetic field is believed to be due to the Earth …
A)
B)
C)
D)
E)
being located less than two astronomical units from the Sun.
being hit by the solar wind
having a Moon.
having an olivine-rich mantle
having a liquid, iron-nickel outer core that is rotating.
8) The Frost Line is the distance from the Sun where …
A)
B)
C)
D)
E)
metallic iron can first start forming
olivine can first start forming
halite can first start forming
water ice can first start forming
pyroxene can first start forming
Astronomy 101, Exam #3
B
9) What is the density of the Earth? Pick the closest value.
A)
B)
C)
D)
E)
1,500 kg/m3
3,500 kg/m3
5,500 kg/m3
7,500 kg/m3
9,500 kg/m3
10) Which gas is not considered a greenhouse gas?
A) CH4
B) H2O
C) O3
D) Ar
E) CO2
11) The two most abundant elements in Saturn are …
A) hydrogen and helium.
B) iron and hydrogen.
C) nitrogen and hydrogen.
D) oxygen and carbon.
E) nitrogen and oxygen.
12) What are “Hot Jupiters”?
A)
B)
C)
D)
E)
Jupiter-sized planets that are found very close to stars
Jupiter-sized planets that experience many impacts
Jupiter-sized planets that have many satellites
Jupiter-sized planets that have rings
Jupiter-sized planets that are radioactive
13) Which of these objects could potentially produce the largest doppler shifts on the
spectral lines of a star?
A) A planet with a mass that is ten times that of Jupiter that is 0.1 AU from
the star
B) A planet with a mass that is eleven times that of Jupiter that is 0.5 AU
from the star
C) A planet with the mass of Earth that is 10 AU from the star
D) A planet with the mass of Earth that is 1 AU from the star
E) A planet with the mass of Jupiter that is 0.1 AU from the star
Astronomy 101, Exam #3
B
14) The two most abundant elements in Jupiter are …
A) hydrogen and helium.
B) iron and hydrogen.
C) nitrogen and hydrogen.
D) oxygen and carbon.
E) nitrogen and oxygen.
15) How many extrasolar planets are currently known? Pick the closest value.
A)
B)
C)
D)
E)
400
600
800
1,000
1,200
16) Put these bodies in order from lowest to highest density.
Lowest density  highest density
A)
B)
C)
D)
E)
Moon, Earth, Jupiter
Moon, Jupiter, Earth
Jupiter, Moon, Earth
Jupiter, Earth, Moon
Earth, Moon, Jupiter
17) Why is it easier to see extrasolar planets from Earth in the infrared than in the
visible?
A) Planets are hotter than stars
B) Stars are not as bright in the infrared while planets tend to be brightest in
the infrared
C) Stars do not give off light in the infrared
D) Planets do not reflect visible light
E) Visible light cannot pass through the Earth’s atmosphere
18) Why isn’t C14 dating used to determine the formation ages of meteorites?
A)
B)
C)
D)
E)
Carbon is not found in meteorites
The half-life of C14 is too short
There is too much C14 in the atmosphere
The Sun produces too much C14 in its atmosphere
C14 will not decay in space
Astronomy 101, Exam #3
B
19) Which is not a difference between terrestrial planets and Jovian planets?
A)
B)
C)
D)
E)
Terrestrial planets are closer to the Sun than Jovian planets
Terrestrial planets have fewer moons than Jovian planets
Jovian planets have many rings while terrestrial planets do not have rings
Terrestrial planets have larger masses than Jovian planets
Jovian planets are primarily gaseous while terrestrial planets are primarily
rocky
20) The hypothesized spherical cloud of comets, which may lie roughly 50,000 AU
from the Sun, is called the …
A)
B)
C)
D)
E)
Kuiper Belt
Magellanic Cloud
Oort Cloud
Main Belt
Hertzsprung-Russell Diagram
21) A stable isotope of an element …
A)
B)
C)
D)
E)
Decays faster than a radioactive isotope of the same element
Is always more massive than a radioactive isotope of the same element
Is always less abundant than a radioactive isotope of the same element
Does not decay to a daughter isotope
Will have a half-life that is less than an hour
22) Which country has never launched a spacecraft to the Moon?
A)
B)
C)
D)
E)
India
United States
Japan
Singapore
Soviet Union
23) South Pole-Aitken Basin is …
A) the largest crater on the Moon
B) the largest crater on Earth
C) the supercontinent that existed before the component continents separated
from it.
D) the mechanically weak region of the upper mantle of the Earth.
E) a type of mineral.
Astronomy 101, Exam #3
B
24) Pangea is …
A) the largest crater on the Moon
B) the largest crater on Earth
C) the supercontinent that existed before the component continents separated
from it.
D) the mechanically weak region of the upper mantle of the Earth.
E) a type of mineral.
25) Olivine is …
A) the largest crater on the Moon
B) the largest crater on Earth
C) the supercontinent that existed before the component continents separated
from it.
D) the mechanically weak region of the upper mantle of the Earth.
E) a type of mineral.
26) The Earth’s crust is predominately made out of …
A)
B)
C)
D)
E)
Fe
Al
Si
Ni
O
27) The transit method discovers planets around other stars by …
A)
B)
C)
D)
E)
Looking for decreases in the brightnesses of the stars
Looking for Doppler shifts of spectral lines
Looking for increases in the brightnesses of the stars
Looking for collisions between the planets and the stars
Looking for gamma-ray emissions from the planets
28) The goal of the Kepler mission is to discover …
A)
B)
C)
D)
E)
Earth-sized planets
Comets
If there is water on the Moon
Moon-sized planets
The origin of the Earth’s magnetic field
Astronomy 101, Exam #3
B
29) The layers of the Earth from the surface to the center are …
Surface  center
A)
B)
C)
D)
E)
Mantle, core, crust
Crust, core, mantle
Crust, mantle, core
Core, mantle, crust
Mantle, crust, core
30) The core of the Moon is predominately made out of …
A)
B)
C)
D)
E)
Fe
Al
Si
Ni
O
31) The Richter Scale measures …
A)
B)
C)
D)
E)
The sizes of craters
The speed of S-waves
The speed of P-waves
The magnitudes of earthquakes
The amount of water on the Moon
32) Why do we think that some meteorites are actually samples of the Moon?
A) The meteorites are radioactive
B) We can compare the meteorites to samples returned from the Apollo
missions
C) The meteorites are primarily composed of carbon
D) The meteorites are older than 5.6 billion years
E) The meteorites have very high concentrations of Nitrogen
33) Regolith is another name for …
A) the mechanically weak region of the upper mantle of the Earth.
B) the Lunar soil
C) the supercontinent that existed before the component continents separated
from it.
D) The Lunar core
E) The fossils found in both South America and Africa
Astronomy 101, Exam #3
34) What type of rock solidified from molten or partially molten material?
A)
B)
C)
D)
E)
Sedimentary
Limestone
Metamorphic
Igneous
Shale
35) The giant impact hypothesis proposes that the Moon formed after …
A)
B)
C)
D)
E)
It was ejected from Mars after a collision
It was ejected from Mercury after a collision
A collision between the young Earth and a Mars-sized body
Two asteroids collided with each other near the Earth
It was ejected from Venus after a collision
36) Which country or countries have returned samples of the Moon to Earth?
A)
B)
C)
D)
E)
Just the United States
Just the Soviet Union
Just Japan
Just the United States, the Soviet Union, and Japan
Just the United States and the Soviet Union
37) The rings of energetic charged particles around Earth that are held in place by
Earth's magnetic field are called the ...
A)
B)
C)
D)
E)
Newton Radiation Belts
Van Allen Radiation Belts
Kuiper Belts
Einstein Belts
Oort Clouds
38) Which of these planets is not considered a Jovian planet?
A)
B)
C)
D)
E)
Jupiter
Uranus
Saturn
Mars
Neptune
B
Astronomy 101, Exam #3
39) The two most abundant elements in the Earth’s atmosphere are …
A) hydrogen and helium.
B) iron and hydrogen.
C) nitrogen and hydrogen.
D) oxygen and carbon.
E) nitrogen and oxygen.
40) Half-life is defined as …
A) The age of the solar system
B) The age of the universe
C) The time required for half the nuclei in a sample of a specific isotopic
species to undergo radioactive decay.
D) The time it takes for half of a surface to become saturated with craters
E) The time it takes for a P-wave to travel to the other side of the Earth
B