Astronomy Final Flashcards
(35 cards)
One light-hour is the distance that light travels in an hour. How far is this, in kilometers? (Recall that the speed of light is 300,000 km/s.)
A) 300,000 km
B) 18 million km
C) 100 million km
D) 1.08 billion km
E) 9.46 trillion
Answer: D
What is the celestial sphere?
A) The celestial sphere is a representation of how the entire sky looks as seen from Earth.
B) The celestial sphere is a model that shows the true locations in space of the Sun and a few thousand of the nearest stars.
C) The celestial sphere is a model of how the stars are arranged in the sky relative to our Sun, which is in the middle of the sphere.
D) It represents a belief in an Earth-centered universe, and hence is no longer considered to have any use.
Answer: A
The distribution of the mass of the Milky Way Galaxy is determined by:
A) counting the number of stars.
B) determining the amount of gas and dust.
C) studying how stars are distributed in the Milky Way.
D) studying the rotation of the galaxy.
E) weighing various parts of the Milky Way.
Answer: D
Which of the following best describes why we have seasons on Earth?:
A) The tilt of Earthʹs axis causes different portions of the Earth to receive more or less direct sunlight at different times of year.
B) Earthʹs elliptical orbit means we are closer to the Sun and therefore receive more intense sunlight at some times of year than at others.
C) The tilt of Earthʹs axis causes the northern hemisphere to be closer to the Sun than the southern hemisphere in summer, and visa versa in winter.
D) The varying speed of Earth in its orbit around the Sun gives us summer when we are moving fastest and winter when we are moving slowest.
Answer: A
Which of the following correctly describes the meridian in your local sky?:
A) a half-circle extending from your horizon due east, through your zenith, to your horizon due west
B) a half-circle extending from your horizon due east, through the north celestial pole, to your horizon due west
C) a half-circle extending from your horizon due north, through your zenith, to your horizon due south
D) the point directly over your head
Answer: C
What conditions are required for a solar eclipse?:
A) The phase of the Moon must be new, and the nodes of the Moonʹs orbit must be nearly aligned with Earth and the Sun.
B) The phase of the Moon must be full, and the nodes of the Moonʹs orbit must be nearly aligned with Earth and the Sun.
C) The phase of the Moon can be new or full, and the nodes of the Moonʹs orbit must be nearly aligned with Earth and the Sun.
D) The phase of the Moon must be new, and the Moonʹs orbital plane must lie in the ecliptic.
E) The phase of the Moon must be full, and the Moonʹs orbital plane must lie in the ecliptic.
Answer: A
What do astronomers mean by a constellation?:
A) A constellation is a region in the sky as seen from Earth.
B) A constellation is a group of stars related through an ancient story.
C) A constellation is any random grouping of stars in the sky.
D) A constellation is a group of stars that are all located in about the same place in space.
Answer: A
According to Keplerʹs third law (p2 = a3), how does a planetʹs mass affect its orbit around the Sun?
A) A planetʹs mass has no effect on its orbit around the Sun.
B) More massive planets orbit the Sun at higher average speed.
C) More massive planets must have more circular orbits.
D) A more massive planet must have a larger semimajor axis.
Answer: A
Momentum is defined as
A) mass times speed.
B) mass times velocity.
C) force times velocity.
D) mass times acceleration. E) force times acceleration.
Answer: B
What quantities does angular momentum depend upon?
A) mass and velocity
B) mass, velocity, and radius
C) force and radius
D) force, velocity, and radius
E) momentum and angular velocity
Answer: B
According to the universal law of gravitation, if you triple the distance between two objects, then the gravitational force between them will
A) increase by a factor of 3.
B) decrease by a factor of 3.
C) decrease by a factor of 6. D) increase by a factor of 9. E) decrease by a factor of 9.
Answer: E
The allowed shapes for orbits under the force of gravity are
A) ellipses only.
B) ellipses and spirals.
C) ellipses, parabolas, and hyperbolas.
D) ellipses, spirals, and parabolas.
E) spirals, circles, and squares.
Answer: C
When light reflects off an object, what is the relation between the angle of incidence and the angle of reflection?
A) angle of incidence = angle of reflection
B) angle of incidence + angle of reflection = 90°
C) angle of incidence + angle of reflection = 180°
D) angle of incidence - angle of reflection = 90°
E) It depends on the material that the light reflects off.
Answer: A
The wavelength of a wave is
A) how strong the wave is.
B) the distance between a peak of the wave and the next trough.
C) the distance between two adjacent peaks of the wave.
D) the distance between where the wave is emitted and where it is absorbed. E) equal to the speed of the wave times the waveʹs frequency.
Answer: C
Suppose you know the frequency of a photon and the speed of light. What else can you determine about the photon?
A) its temperature
B) its acceleration
C) its wavelength and energy
D) the chemical composition of the object that emitted it
Answer: C
An atom which has 4 protons and 6 neutrons will be electrically neutral if it contains
A) 4 electrons.
B) 6 electrons.
C) 10 electrons.
D) at least one electron.
Answer: A
The jovian planets in our solar system are
A) Mercury, Venus, Earth, and Mars.
B) Jupiter, Saturn, Uranus, Neptune, Pluto, and Eris. C) Jupiter, Saturn, Uranus, and Neptune.
D) Io, Europa, Ganymede, and Callisto.
Answer: C
Which of the following planets has an horizontal spin axis?
A) Jupiter
B) Venus
C) Uranus
D) Saturn
Answer: C
The proper order of the layers of a generic atmosphere from lowest altitude to highest is
A) troposphere, stratosphere, exosphere, thermosphere.
B) troposphere, stratosphere, thermosphere, exosphere.
C) stratosphere, troposphere, exosphere, thermosphere.
D) stratosphere, troposphere, thermosphere, exosphere. E) none of the above
Answer: B
Sunsets are red because
A) the Sun emits more red light when itʹs setting.
B) sunlight must pass through more atmosphere then, and the atmosphere scatters even more light at bluer wavelengths, transmitting mostly red light.
C) sunlight must pass through more atmosphere then, and the atmosphere scatters more light at red wavelengths than bluer wavelengths.
D) the cooler atmosphere in the evening absorbs more blue light.
E) none of the above
Answer: B
What kind of material in the solar nebula could remain solid at temperatures as high as 1,500 K, such as existed in the inner regions of the nebula?
A) rocks
B) metals
C) silicon-based minerals
D) hydrogen compounds
E) molecules such as methane and ammonia
Answer: B
The age of our solar system is approximately
A) 10,000 years.
B) 3.8 million years.
C) 4.6 million years.
D) 4.6 billion years.
E) 14 billion years.
Answer: D
According to modern science, what was the approximate chemical composition of the solar nebula?
A) 50% hydrogen and helium, 50% everything else
B) 98% hydrogen and helium, 2% everything else
C) 98% hydrogen, 2% helium
D) roughly equal proportions of hydrogen, helium, water, and methane
Answer: B
What do we mean by accretion in the context of planet formation?
A) the formation of moons around planets
B) the growth of planetesimals from smaller solid particles that collided and stuck together
C) the solidification of ices, rocks, and metal from the gas of the solar nebular
D) the growth of the Sun as the density of gas increased in the center of the solar nebula
Answer: B
