American Public University:SCIN 134 Final Exam;100% score

Question 1 of 36 2.0 Points A star that is spectral class A is hotter than a star of spectral class O. True False Question 2 of 36 2.0 Points It can take hundreds of billions of years for a red dwarf to convert all of its hydrogen completely to helium. True False Question 3 of 36 2.0 Points Red stars are relatively “cold”, with low surface temperatures. True False Question 4 of 36 2.0 Points A white dwarf is approximately the same size as the Earth. True False Question 5 of 36 2.0 Points Fusion only occurs on the surface of the Sun. True False Question 6 of 36 2.0 Points In the conversion from hydrogen to helium, four protons are converted to one helium nucleus. True False Question 7 of 36 2.0 Points Occam’s razor is the idea that the most simple and most straightforward explanation of observations in nature is most likely to be the correct one. True False Question 8 of 36 2.0 Points Sunspots are dark because they are hotter than the surrounding material on the Sun. True False Question 9 of 36 2.0 Points All of the terrestrial planets have plate tectonics with converging and spreading plates similar to Earth’s. True False Question 10 of 36 2.0 Points Red stars are hot and blue stars are cold. True False Question 11 of 36 2.0 Points The Galaxy rotates like a solid disk, like a CD or DVD. True False Question 12 of 36 2.0 Points Evidence suggests that planetary formation around stars like the Sun are very uncommon. True False Question 13 of 36 2.0 Points Gravitational lensing involves using a special type of lens in a telescope to view gravitational waves. True False Question 14 of 36 2.0 Points Two prominent research groups came to the same surprising conclusion after taking measurements of the luminosity of Type Ia supernovae at great distances, this being that the universe is accelerating while it expands. True False Question 15 of 36 2.0 Points Light has properties of both waves and particles. True False Question 16 of 36 3.0 Points What is the solar wind? A.the storm of waves and vortices on the Sun’s surface generated by a solar flare. B.the constant flux of photons from the Sun’s visible surface. C.the circulation of gases between the equator and the poles of the Sun. D.the Sun’s outer atmosphere streaming out into space. Question 17 of 36 3.0 Points The temperature of the Sun’s photosphere is: A.about 10,000 K. B.4400 K. C.5800 K. D.close to 1 million K. Question 18 of 36 3.0 Points Where do we find the most massive stars on the main sequence in a Hertzsprung-Russell diagram? A.upper left B.They all have approximately the same mass, because this is what defines the main sequence. C.lower right D.center, with lower mass stars on either side Question 19 of 36 3.0 Points The luminosity of a star is: A.another name for its color or surface temperature. B.its brightness as seen by people on Earth. C.its total energy output into all space over all wavelengths. D.its brightness at a hypothetical distance of 10 parsecs (32.6 light-years) from Earth. Question 20 of 36 3.0 Points What places a limit on the lifetime of a star? A.Loss of the mass, and therefore of nuclear fuel, of the star into space by stellar winds. B.The amount of available nuclear fuel it contains. C.Collisions between stars in a galaxy are sufficiently frequent that all stars will eventually be destroyed in this way. D.Buildup of spin as it evolves and contracts means that the star will eventually spin apart. Question 21 of 36 3.0 Points The most likely places in which stars and planetary systems are forming in the universe are: A.the rarified outer space between galaxies. B.regions of hot gas in the spiral arms of galaxies. C.gas and dust nebulae. D.the centers of galaxies. Question 22 of 36 3.0 Points X rays that come from the vicinity of a black hole actually originate from: A.well inside the event horizon. B.its exact center, or singularity. C.relatively far away from the black hole, where matter is still relatively cool. D.just outside the event horizon, on the accretion disk. Question 23 of 36 3.0 Points Black holes are so named because A.they emit a perfect blackbody spectrum. B.no light or any other electromagnetic radiation can escape from inside them. C.all their electromagnetic radiation is gravitationally redshifted to the infrared, which leaves no light in the optical region. D.they emit no visible light, their only spectral lines are in the radio and infrared. Question 24 of 36 3.0 Points Spectral lines are of particular importance in astronomy because: A.each different element has a characteristic line spectrum. B.they can be observed through a diffraction grating. C.they are the only light bright enough to be seen at large distances. D.only stars produce bright line spectra. Question 25 of 36 3.0 Points A significant contribution of Kepler to our understanding of the solar system was: the discovery that Earth orbits the Sun. B.the discovery that planetary orbits are not circular. C.the observation of the phases of Venus. D.the idea of a gravitational force between Earth and the Sun. Question 26 of 36 2.0 Points The age of Earth is considered to be: A.about 100 million years. B.about 4.6 million years. C.about 4.6 billion years. D.93 million years. Question 27 of 36 3.0 Points Rings of dust and icy particles are found around which planets? A.all planets that have moons associated with them. B.all four of the Jovian planets. C.all four of the terrestrial planets. D.only Saturn. Question 28 of 36 3.0 Points What are the most energetic eruptive events to occur on the Sun? A.thermonuclear explosions B.erupting prominences C.coronal mass ejections D.solar flares Question 29 of 36 3.0 Points Compared to a star in the middle of the diagram, a star in the lower left part of the Hertzsprung-Russell diagram is: A.brighter. smaller. C.cooler. D.larger. Question 30 of 36 3.0 Points Our Sun will end its life by becoming a: A.black hole. B.white dwarf. C.molecular cloud. D.pulsar. Question 31 of 36 3.0 Points The central core of the Galaxy is in the direction of: A.the Ring Nebula. B.the North Star. C.Sagittarius A*. D.Orion’s belt. Question 32 of 36 3.0 Points How are galaxies spread throughout the universe? A.They are grouped into clusters that are spread more-or-less evenly throughout the universe. B.They are grouped into clusters, which are, in turn, grouped into clusters ofclusters (superclusters). C.Galaxies are densest near the Milky Way Galaxy and become less and less numerous the farther we look out into the universe. D.Galaxies are spread more-or-less evenly throughout the universe Question 33 of 36 5.0 Points What is the reason why we have seasons on the Earth? Give as much detail as you can in your own words, but be careful…if you include a misconception, the score is 0. Question 34 of 36 5.0 Points Explain in your own words why we see different phases of the Moon. Identify each of the four major phases, along with a description of what is occurring to allow us to see each of them. Bonus point: At what time is each major phase visible at the Moon’s highest point in the sky? Question 35 of 36 5.0 Points How does Einstein’s famous equation, E = mc2, relate to the production of the Sun’s energy? Be sure to include what each factor in the equation represents with respect to what happens inside the Sun. Question 36 of 36 5.0 Points Identify and describe in your own words three separate and specific pieces of scientific evidence that support the Big Bang theory?