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- AST1002 Section 2: Test 2 Date: 11/06/2008 Name: Equations: E = m c2 Question 1: The Sun is a stable star because 1. gravity balances forces from pressure. (!) 2. the rate of fusion equals the rate of ssion. 3. radiation and convection balance. 4. mass is converted into energy. 5. fusion doesnt depend on temperature. Question 2: What is thought to cause Ios volcanism? 1. Jupiters magnetosphere 2. Tidal stresses from both Jupiter and Europa (!) 3. Jupiters rapid rotation 4. Radioactive decay from its core 5. Ios large mass and tectonic activity Question 3: The magnetic elds of which two planets are most unusual? 1. Jupiter and Neptune 2. Jupiter and Saturn 3. Jupiter and Earth 4. Saturn and Earth 5. Uranus and Neptune (!) Review HW7 Miniquiz 6, Q3 Question 4: Rigel has an apparent magnitude of +0.18 and Betelgeuse an apparent magnitude of +0.45. What can you conclude from this? 1. Rigel must be closer to Earth. 2. Betelgeuse must be closer to Earth. 3. Rigel is brighter than Betelgeuse. (!) 4. Betelgeuse is brighter than Rigel. 5. Both stars are brighter than the full Moon. Review Question 5: Some regions along the plane of the Milky Way appear dark because 1. there are no stars in these areas. 2. stars in that region are hidden by interstellar gas. 3. stars in that region are hidden by dark dust particles. (!) HW9 4. many brown dwarfs in those areas absorb light which they turn into heat. 5. many black holes absorb all light from those directions. Question 6: The critical temperature the core must reach for a star to shine by fusion is 1. 5,800 K. 2. 11,000 K. 3. 127,000 K. 4. 10 million K. (!) 5. 100 million K. Question 7: Interstellar dust clouds are best observed at what wavelength? 1. Visible only 2. Radio and infrared (!) 3. UV and infrared 4. Radio and X-ray 5. Visible and UV Question 8: Which are the four Galilean moons of Jupiter? 1. Europa, Titan, Ganymede, and Callisto 2. Io, Ganymede, Callisto, and Titan 3. Europa, Ganymede, Io, and Triton 4. Io, Europa, Ganymede, and Callisto (!) 5. Io, Titan, Triton, and Charon Question 9: Inside the Roche Limit 1. large moons are torn apart. (!) 2. is where large moons form. 3. ring systems cannot exist. 4. there is a gap in a planets magnetic eld. 5. hydrogen can only exist in its liquid metallic form. Miniquiz 6, Q4 HW7 Review Review Question 10: A cloud fragment too small to collapse into a main sequence star becomes a 1. white dwarf. 2. pulsar. 3. T Tauri object. 4. planet of another star. 5. brown dwarf. (!) Question 11: A moon with a smooth, uncratered surface would imply 1. meteorites have never struck the moon. 2. a strong magnetic eld surrounds the moon. 3. the surface is very young. (!) 4. the moon lies within the planets Roche limit. 5. the surface is completely liquid. Question 12: How do the atmospheres of Earths Moon and Mercury compare? 1. Mercurys is more dense with carbon dioxide. 2. They are similar, only 1 % as dense as ours. 3. The cooler Moon retains a thicker nitrogen atmosphere. 4. As no spacecraft has yet landed there, no information exists about Mercurys. 5. Neither body has a permanent atmosphere. (!) Question 13: On the H-R diagram, red supergiants like Betelgeuse lie 1. at the top right. (!) 2. at the top left. 3. about the middle. 4. to the lower left edge. 5. on the bottom, coolest portion of the main sequence. Question 14: The reason the Jovian planets lost very little of their original atmosphere is due to their 1. rapid rotation. 2. strong magnetic elds. 3. ring systems. 4. many moons. 5. large mass. (!) Review Question 15: A solar-mass star will evolve o the main sequence when 1. it completely runs out of hydrogen. 2. it expels a planetary nebula to cool o and release radiation. 3. it explodes as a violent nova. 4. it loses all its neutrinos, so fusion must cease. 5. it builds up a core of inert helium. (!) Miniquiz 8, Q1 Question 16: Today, the primary source of the Suns energy is 1. oxidation of carbon in the core. 2. gravitational collapse of the helium coreward. 3. dark energy. 4. the strong force fusing hydrogen into helium. (!) HW8 5. the weak force creating energy from uranium decay. Question 17: Of the elements in body, your the only one not formed in stars is 1. Carbon 2. Calcium 3. Iron 4. Aluminum 5. Hydrogen (!) Question 18: A star will spend most of its life 1. as a protostar. 2. on the main sequence. (!) 3. inside its planetary nebula. 4. in repeated swellings to the red giant. 5. in a sustained helium ash lasting billions of years. Question 19: Emission nebulae like M-42 occur only near stars that emit large amounts of 1. visible light. 2. microwaves. 3. ultraviolet radiation. (!) 4. infrared heat. 5. x-rays and gamma rays. HW9 HW9 Question 20: Stellar parallax is used to measure the 1. sizes of stars. 2. distances of stars. (!) 3. temperatures of stars. 4. radial velocity of stars. 5. brightness of stars. Question 21: The speed of light is 3 108 m/s. If 2.00 kg of mass is converted to energy, how much energy will be produced? 1. 1.8 1017 J (!) 2. 6.0 108 J 3. 1.5 108 J 4. 6.0 104 J 5. 9.0 1016 J Question 22: A stars apparent magnitude is a number used to describe how our eyes measure its 1. distance. 2. temperature. 3. brightness. (!) 4. absolute luminosity. 5. radial velocity. Question 23: What would Jupiter have needed to be a star? 1. More mass to make the planet hotter (!) 2. A larger satellite system 3. More uranium to ignite nuclear ssion chain reactions in its core 4. A slower spin, similar to the Suns 25 days, instead of its present 10 hours 5. A dierent chemical composition HW8 Question 24: The parallax of a certain star was found to be 0.01 arc-seconds. Find the distance to this star in pc. 1. 0.01 parsecs 2. 0.1 parsecs 3. 1 parsec 4. 10 parsecs 5. 100 parsecs (!) HW8 Question 25: The temperature of the Suns photosphere is about 1. 3,200 K 2. 5,800 K (!) 3. 11,000 K 4. one million K 5. ten million K Question 26: A stars color index directly tells us its 1. temperature. (!) 2. proper motion. 3. distance. 4. radial velocity. 5. age. Question 27: Many astronomers believe Pluto is perhaps best classied as 1. a cold terrestrial planet. 2. a small Jovian planet. 3. a large Kuiper Belt object. (!) 4. a wandering moon. 5. a captured comet. Question 28: The number of sunspots and solar activity in general peaks 1. every 27 days, the apparent rotation period of the Suns surface. 2. once a year. 3. every 5 1/2 years. 4. every 11 years. (!) Review Miniquiz 7, Q4 Miniquiz 6, Q1 5. approximately every 100 years. Question 29: Which moon in the solar system shows a dense atmosphere? 1. Our Moon 2. Titan (!) 3. Phobos 4. Europa 5. Triton Question 30: Interstellar gas...

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