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Astronomy 101, Exam #2
C
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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) Why were the first images from the Hubble Space Telescope blurry?
A)
B)
C)
D)
E)
The gyroscopes were faulty.
The telescope was too hot.
The lenses were too thick.
The mirror was too flat at the edges
The telescope was too heavy.
2) If it is 400o Celsius, what is the temperature in Kelvin?
A)
B)
C)
D)
E)
27.15 Kelvin
136.85 Kelvin
573.15 Kelvin
883.15 Kelvin
673.15 Kelvin
3) From a measurement in the laboratory, we know that a particular spectral line
formed by hydrogen appears at a wavelength of 486.1 nm. The spectrum of a
particular star shows the same hydrogen line appearing at a wavelength of 485.7
nm. What can we conclude from this observation?
A) The star is getting hotter.
B) The star must be very distant.
C) The star is getting colder.
D) The star is moving toward us.
E) The star is moving away from us.
Astronomy 101, Exam #2
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4) What was the purpose of the LCROSS (Lunar CRater Observation and Sensing
Satellite) mission?
A) to determine if the Moon has a magnetic field
B) to spectrally map the Moon’s equator.
C) to try to detect the presence of water on the Moon.
D) to look for life on the Moon.
E) to determine the distance of the Moon to Earth.
5) An infrared photon has a frequency of 1 x 1013 Hz. What is the wavelength of
this photon?
A)
B)
C)
D)
E)
3 x 10-5 meters
6.626 x 10-21 meters
3 x 108 meters
6.626 x 10-6 meters
3 x 1021 meters
6) You drop a 4 kg ball and an 8 kg ball from a height of one meter at the same exact
time on the Moon. Which of these statements is true?
A)
B)
C)
D)
E)
The 4 kg ball and the 8 kg ball will fall at the same rate.
The 8 kg ball will fall twice as fast as the 4 kg ball.
The 8 kg ball will fall four times as fast as the 4 kg ball.
The 8 kg ball will fall eight times as fast as the 4 kg ball.
The 8 kg ball will fall sixteen times as fast as the 4 kg ball.
7) As the wavelengths of photons of light increase, their …
A)
B)
C)
D)
E)
Frequencies increase and their energies increase
Frequencies decrease and their energies increase
Frequencies decrease and their energies decrease
Frequencies increase and their energies stay the same
Frequencies stay the same and their energies stay the same
8) Which of the following objects has the most kinetic energy?
A) A 10 kg mass moving at 1 km/s.
B) A 2 kg mass moving at 2 km/s.
C) A 2 kg mass moving at 5 km/s.
D) A 5 kg mass moving at 2 km/s.
E) A 3 kg mass moving at 3 km/s.
Astronomy 101, Exam #2
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9) Why was the newly discovered ring around Saturn discovered with a satellite that
could measure infrared light and not with a satellite that could measure visible light?
A) no satellites that could measure visible light are currently in space
B) the particles in the rings are so cold that they are brighter in the infrared
than in the visible
C) visible light can’t penetrate the Earth’s atmosphere
D) visible light can’t travel through dust
E) infrared light has a much longer frequency than visible light so it is easier to
detect in space
10) In space, a 10 Newton force on a 2 kg body would give that body an acceleration of
…
A) 2 m/s2
B) 5 m/s2
C) 20 m/s2
D) 40 m/s2
E) 100 m/s2
11) You heat a black ball from a temperature of 400 Kelvin to a temperature of 800
Kelvin. Which of these statements is true?
A)
B)
C)
D)
E)
Twice as much energy per second is emitted by the hotter body.
Four times as much energy per second is emitted by the hotter body.
Eight times as much energy per second is emitted by the hotter body.
Sixteen times as much energy per second is emitted by the hotter body.
Three hundred times as much energy per second is emitted by the hotter body.
12) Who determined the value of the Gravitational Constant?
A) Isaac Newton
B) Albert Einstein
C) Henry Cavendish
D) Tycho Brahe
E) Johannes Kepler
13) The nucleus of an atom may contain …
A) neutrons and electrons.
B) protons and neutrons.
C) ions.
D) protons and electrons.
E) neutrinos and electrons
Astronomy 101, Exam #2
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14) Kinetic energy is usually given in units of …
A)
B)
C)
D)
E)
Newtons
Kilograms
Joules
Hertz
Gauss
15) You take an image of the sky. On the image, a star has an apparent magnitude of +8,
a main-belt asteroid has an apparent magnitude of +6, a Kuiper Belt Object has an
apparent magnitude of +17, a Trojan asteroid has an apparent magnitude of +14, and
Pluto has an apparent magnitude of +15. Which object is brightest in the sky?
A)
B)
C)
D)
E)
The star
The main-belt asteroid
The Kuiper Belt Object
The Trojan asteroid
Pluto
16) What is the frequency of a photon of light if the wavelength is 1 x 105 meters?
A)
B)
C)
D)
E)
1 x 1016 Hertz
3 x 1016 Hertz
3 x 1013 Hertz
9 x 1010 Hertz
3 x 103 Hertz
17) Which two bodies have the strongest attractive force between them?
A) Two 1 kg balls that are 1 meter apart.
B) Two bodies each with the mass of the Sun that are one light year apart.
C) Two bodies each with the mass of the Earth that are 1 AU apart.
D) Two bodies each with the mass of Jupiter that are 10 AU apart.
E) Two 100 kg balls that are 1 km apart.
18) Which is not a real advantage of a space-based telescope compared to an Earthbased telescope?
A) It can be open 24 hours and 7 days of week
B) The space-based telescope is closer to the objects it studies.
C) You do not have to worry about distorting effects of atmosphere
D) There is no extra background of light due to scattering of light in the Earth’s
atmosphere.
E) You can observe in more wavelength regions
Astronomy 101, Exam #2
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19) How would the force of gravity between the Sun and the Earth change if the Sun's
mass were increased by a factor of four and the Earth’s mass was increased by a factor of
four?
A) The force would be unchanged.
B) The force would increase by a factor of 4.
C) The force would increase by a factor of 16.
D) The force would decrease by a factor of 4.
E) The force would decrease by a factor of 16.
20) What is the gravitational acceleration on the surface of a planet that has 4 times the
mass of Earth and 2 times the radius of Earth?
A)
B)
C)
D)
E)
9.8 m/s2
4.9 m/s2
19.6 m/s2
4.0 m/s2
11.8 m/s2
21) If the Earth were moved to a distance of 2 AU from the Sun, how much stronger or
weaker would be the gravitational force between the Sun and Earth?
A) The force would be 2 times stronger.
B) The force would be 4 times stronger.
C) The force would be unchanged.
D) The force would be 2 times weaker.
E) The force would be 4 times weaker.
22) Why are gamma-ray telescopes located in space and not on the surface of the Earth?
A)
B)
C)
D)
E)
Gamma rays are dangerous to humans.
Gamma rays cannot penetrate the Earth’s atmosphere
Gamma rays tend to make the telescope radioactive
Gamma rays penetrate deep into the ground
Gamma rays do not interact with silicon properly on the surface of the Earth
23) Somebody says that a spectrum of a star appears redshifted. What is happening to the
star?
A)
B)
C)
D)
E)
The star is getting hotter
The star is getting colder
The star is moving towards you.
The star is moving away from you
The star is getting larger
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Astronomy 101, Exam #2
24) A star is 10 light years from Earth. The star is moved so it is 5 light years from Earth.
How will the apparent brightness of the star change?
A)
B)
C)
D)
E)
The apparent brightness will not change
The apparent brightness will become twice as bright.
The apparent brightness will become four times as bright
The apparent brightness will become eight times as bright.
The apparent brightness will become sixteen times as bright.
25) Different elements always have different numbers of …
A)
B)
C)
D)
E)
Neutrons
Protons
Isotopes
Neurons
Neutrinos
26) One gram of uranium is completely turned into energy.
produced?
A)
B)
C)
D)
E)
How much energy is
9 x 1016 Joules
3 x 1016 Joules
9 x 1013 Joules
3 x 1016 Joules
1 x 1016 Joules
27) Put these parts of the electromagnetic spectrum in order from shortest wavelength to
longest wavelength:
Shortest  Longest wavelength
A)
B)
C)
D)
E)
Gamma-ray, X-ray, ultraviolet, infrared, visible, radio
Gamma-ray, X-ray, ultraviolet, visible, infrared, radio
X-ray, gamma-ray, ultraviolet, visible, infrared, radio
Radio, gamma-ray, X-ray, ultraviolet, visible, infrared
Radio, infrared, visible, ultraviolet, X-ray, Gamma-ray
28) Put these parts of the electromagnetic spectrum in order from lowest frequency to
highest frequency:
Lowest  Highest frequency
A)
B)
C)
D)
E)
Radio, infrared, visible, ultraviolet, X-ray, gamma-ray
Gamma-ray, X-ray, ultraviolet, visible, infrared, radio
Radio, visible, ultraviolet, X-ray, gamma-ray, infrared
Gamma-ray, X-ray, ultraviolet, visible, radio, infrared
Radio, X-ray, infrared, ultraviolet, visible, gamma-ray
Astronomy 101, Exam #2
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29) Put these parts of the electromagnetic spectrum in order from lowest energy to
highest energy:
Lowest  Highest energy
A)
B)
C)
D)
E)
Gamma-ray, X-ray, ultraviolet, infrared, visible, radio
Gamma-ray, X-ray, ultraviolet, visible, infrared, radio
X-ray, gamma-ray, ultraviolet, visible, infrared, radio
Radio, gamma-ray, X-ray, ultraviolet, visible, infrared
Radio, infrared, visible, ultraviolet, X-ray, Gamma-ray
30) As the temperature decreases for an object, the peak of the black-body radiation
curve measured for the object moves to …
A)
B)
C)
D)
E)
lower intensities and longer wavelengths
higher intensities and shorter wavelengths
lower intensities and shorter wavelengths
higher intensities and longer wavelengths
does not change in intensity or in wavelength position
31) The escape velocity for a rocket to break free from the gravitational field of a planet
is related to what properties of the planet and spacecraft.
A)
B)
C)
D)
E)
just the mass of the planet
just the mass of the planet and the radius of the planet
just the radius of the planet
just the mass of the rocket
just the mass of the rocket and the mass of the planet
32) What is a CCD (which stands for charge-coupled device) used for?
A) It is the world's largest operating telescope.
B) It refers to any kind of instrument that can be hooked up to a telescope.
C) It is an electronic detector that can be used in place of photographic film for
taking images of the sky.
D) It is a unit used by astronomers to measure angular resolution.
E) It is the next telescope that will be launched into space.
Astronomy 101, Exam #2
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33) Which is not a reason why all large modern telescopes tend to be reflectors?
A) It is much easier to make a high-quality mirror than the same quality lens
B) Large mirrors are much lighter than large lenses
C) Lenses focus different wavelengths of light slightly differently. Mirrors do
not have this problem
D) Some wavelengths of light can be significantly absorbed by the lens.
E) Lenses cannot be used to observe astronomical objects.
34) Which is not a phase of matter?
A) gas
B) solid
C) liquid
D) psion
E) gas
35) The temperature in this room is closest to what temperature in Kelvin?
A)
B)
C)
D)
E)
100 Kelvin
200 Kelvin
300 Kelvin
400 Kelvin
500 Kelvin
36) A prism can be used to break light up into its constituent spectral colors since
different wavelengths of light are refracted differently by glass and leave the prism at
different angles. What is the order of the colors of light from shortest to longest
wavelength?
Shortest  Longest wavelength
A)
B)
C)
D)
E)
Violet, Indigo, Red, Blue, Green, Yellow, Orange
Red, Orange, Yellow, Green, Blue, Indigo, Violet
Red, Yellow, Orange, Blue, Green, Indigo, Violet
Violet, Indigo, Green, Blue, Orange, Yellow, Red
Violet, Indigo, Blue, Green, Yellow, Orange, Red
37) Light can act as which of the following?
A)
B)
C)
D)
E)
Only as a particle
Only as an isotope
Only as a wave
As a particle and a wave
Only as an ion
Astronomy 101, Exam #2
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38) Why is the Sun’s tidal effect on the Earth about one-half that of the Moon?
A) The gravitational attraction between the Sun and the Earth is smaller than the
gravitational attraction between the Earth and the Moon.
B) The Moon rotates around the Earth while the Earth rotates around the Sun.
C) Since the Sun is farther away, the differential force from one side of the Earth
to the other due to the Sun is smaller than the differential force on the Earth
due to the Moon
D) The Moon is covered with craters
E) The Sun is much more massive than the Moon
39) The smallest tides on Earth occur during which phases of the Moon?
A)
B)
C)
D)
E)
first-quarter and third-quarter
new and full
waning crescent and waxing crescent
waning gibbous and waxing gibbous
waning crescent and waxing gibbous
40) Who was the first to propose the formula E=mc2 for converting matter into energy?
A) Isaac Newton
B) Albert Einstein
C) Henry Cavendish
D) Tycho Brahe
E) Johannes Kepler