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Astronomy 101, Exam #3 Review
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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
-34
h = 6.626 x 10 J●s
mass of Earth = 5.97 × 1024 kg
mass of Sun = 1.99 x 1030 kg
G = 6.67 × 10-11 m3 kg-1 s-2
22
mass of Moon = 7.36 x 10 kg
mass of Jupiter = 1.90 x 1027 kg
2
-8
g = 9.8 m/s
σ = 5.67 x 10 W m-2 K-4
1 eV = 1.60 x 10-19 joules
1 nm = 1 x 10-9 meters radius of Earth = 6.38 × 106 meters
1) Assume that 239U has a half-life of 23 minutes and decays into 239Np. You initially
start with 100 grams of pure 239U. How many grams of 239Np will you have in 46
minutes?
A) 25 grams
B) 50 grams
C) 75 grams
D) 100 grams
E) 12.5 grams
2) How old is the solar system currently assumed to be?
A) 3.6 million years old
B) 2.8 billion years old
C) 4.6 billion years old
D) 6.2 billion years old
E) 657 million years old
3) How old is the universe currently assumed to be?
A) 1.7 billion years old
B) 13.7 billion years old
C) 4.6 billion years old
D) 24.2 billion years old
E) 13.4 million years old
Astronomy 101, Exam #3 Review
4) 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
1.25 x 109 years?
A) 250 grams
B) 500 grams
C) 125 grams
D) 100 grams
E) 50 grams
5) Which is true about P- and S-waves?
A) P-waves can travel through liquids 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 a gas while S-waves cannot travel through
liquids.
E) P-waves cannot travel through solid material while S-waves cannot travel
through liquids.
6) Who was the first man to walk on the Moon?
A)
B)
C)
D)
E)
Buzz Aldrin
Stan Love
Neil Armstrong
Tom Jones
John Glenn
7) A large, dark, basaltic plain on Earth's Moon that was formed by an ancient basaltic
flood eruption and caused by an extremely large asteroid impact is an example of a
Lunar …
A)
B)
C)
D)
E)
Highland
Mare
Estuary
Channel
Eclipse
Astronomy 101, Exam #3 Review
8) Earth is believed to have a magnetic field because …
A)
B)
C)
D)
E)
it is located less than two astronomical units from the Sun.
it is hit by the solar wind
it has a liquid, iron-nickel outer core that is rotating.
it has a Moon.
it has an olivine-rich mantle
9) 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
10) The density of a material is 3.1 g/cm3. What is the density in kg/m3?
A)
B)
C)
D)
E)
3.1 x 1012 kg/m3
31,000 kg/m3
310 kg/m3
31 kg/m3
3,100 kg/m3
11) An object with a mass of 5 x 1018 kg has a diameter of 200 km. What is its
density?
A)
B)
C)
D)
E)
1.197 x 1015 kg/m3
1.197 x 1012 kg/m3
11,197 kg/m3
1,197 kg/m3
1.197 kg/m3
12) Which gas is considered a greenhouse gas?
A) Ar
B) H2
C) He
D) CO2
E) Kr
Astronomy 101, Exam #3 Review
13) Which age is closest to the current age of the Sun calculated from the radioactive
dating of elements in meteorites?
A)
B)
C)
D)
E)
1 million years
5 million years
1 billion years
5 billion years
50 billion years
14) The two most abundant elements in the Sun are?
A) oxygen and carbon.
B) iron and hydrogen.
C) carbon and iron.
D) hydrogen and helium.
E) iron and helium.
15) What are “Hot Jupiters”?
A)
B)
C)
D)
E)
Jupiter-sized planets that are found very close to stars
Jupiter-sized planets that have very hot interiors
Jupiter-sized planets that have many satellites
Jupiter-sized planets that have rings
Jupiter-sized planets that are radioactive
16) Why were the first planets that were discovered around other stars much bigger
than Earth and found very close to their stars?
A) These planets produce a larger gravitational force on the star than an
Earth-like planet far from the star
B) These planets produce a smaller gravitational force on the star than an
Earth-like planet far from the star
C) Earth-like planets can’t form around other stars
D) Jupiter-sized planets are radioactive
E) Jupiter-sized planets have hotter surface temperatures
17) The density of a material is 4,100 kg/m3. What is the density in g/cm3?
A)
B)
C)
D)
E)
4.1 x 1012 g/cm3
1.400 g/cm3
4.1 x 10-3 g/cm3
41 g/cm3
4.100 g/cm3
Astronomy 101, Exam #3 Review
18) An object with a mass of 1 x 1019 kg has a diameter of 200 km. What is its
density?
A)
B)
C)
D)
E)
2.017 kg/m3
1.897 x 1012 kg/m3
1,897 kg/m3
2,387 kg/m3
4,297 kg/m3
19) Density equals …
A) volume/mass
B) mass/area
C) mass/velocity
D) area/mass
E) mass/volume
20) The Greenhouse Effect is where …
A) visible light is absorbed by the atmosphere of a planet
B) visible light is reflected by the atmosphere of a planet.
C) visible light is absorbed by the surface of a planet and the emitted thermal
radiation from the surface is absorbed and reradiated by gases in the atmosphere.
D) thermal radiation is absorbed by the surface of a planet and the emitted thermal
radiation from the surface is absorbed and reradiated by gases in the atmosphere.
E) visible light is absorbed by the surface of a planet and the emitted gamma-rays
and X-rays from the surface are absorbed and reradiated by gases in the
atmosphere.
21) The Greenhouse Effect …
A)
B)
C)
D)
E)
occurs on Venus, but not on Earth
does not occur on Venus or Earth
occurs on Mars, but not on Earth
occurs on Mercury, but not on Earth
occurs on Venus and Earth
Astronomy 101, Exam #3 Review
22) The radial velocity method detects planets by …
A) looking for changes in the lightcurve due to the planet passing in front of the
star.
B) measuring changes in the radio emissions from the star due to the planet
passing in front of the star.
C) detecting Doppler shifts in absorption lines due to the planet gravitationally
pulling on the star
D) measuring infrared peaks in the blackbody spectrum due to the planet passing
in front of the star.
E) seeing gamma ray bursts from material from the planet impacting the star.