Astronomy college course/Star (Wikipedia)/questions
Testbank[1] Astronomy_college_course#Star
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AstroWikipStar_Study
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AstroWikipStar_Study-v1s1
1. Why is a star made of plasma?
- ___ a) it is so hot that electrons are stripped away from the protons
- ___ b) plasma is always present when there are strong magnetic fields
- ___ c) the interstellar gas was mostly plasma
- ___ d) plasma is generic word for "important"
- ___ e) the intense gravity liquifies the substance, just as red blood cells liquify plasma in the body
2. What is the difference between a constellation and an asterism?
- ___ a) asterisms are smaller than constellations
- ___ b) none of these is correct
- ___ c) constellations represent regions of the sky, like state boundaries on a map of the USA
- ___ d) asterisms are larger than constellations
- ___ e) constellations consist of never more than ten stars.
3. Stellar parallax is
- ___ a) Two of these is correct
- ___ b) Triangulation to deduce the distance to nearby stars
- ___ c) Using changes in the angular position of a star to deduce the star’s distance
- ___ d) Using spectral lines to deduce the distance to nearby stars
- ___ e) None of these is correct.
4. Giant molecular clouds with sufficient conditions to form a star cluster would have formed them long ago. Any stellar births in the past couple of billions years probably resulted from _____ between clouds.
- ___ a) photon exchange
- ___ b) collisions
- ___ c) None of these is correct.
- ___ d) ion exchange
- ___ e) Two of these are correct
5. A starburst galaxy.
- ___ a) Two of these are correct
- ___ b) All of these are correct
- ___ c) usually is a result of collisions between galaxies
- ___ d) is a region of active stellar birth
- ___ e) has only dead or dying stars
6. Which of the following expresses Jean's criterion for the collapse of a giant molecular cloud of mass, M, radius, R, and temperature T, and pressure P? (Here ? is some constant)
- ___ a) P>?MR
- ___ b) R>?MT
- ___ c) M>?RT
- ___ d) T>?RM
- ___ e) P>?MT
7. Which of the following changes in the properties of a giant molecular cloud might cause it to collapse?
- ___ a) Decrease mass at fixed temperature and size
- ___ b) Two of these are correct
- ___ c) Increase mass at fixed temperature and size
- ___ d) Increase temperature at fixed mass and size
- ___ e) Increase size at fixed pressure and mass
8. What happens if you increase the size of a giant molecular cloud while keeping temperature and mass fixed?
- ___ a) It is more likely to collapse because this will increase the temperature
- ___ b) It is less likely to collapse because temperature can never be kept fixed
- ___ c) It is more likely to collapse because larger things have more gravity
- ___ d) It is equally likely to collapse because size is not part of the Jean's criterion.
- ___ e) It is less likely to collapse spreading it out weakens the force of gravity
9. What is a Bok globule in the formation of stellar systems?
- ___ a) A black hole that enters a cloud and triggers the collapse
- ___ b) A small planet that formed before any stars have formed
- ___ c) A supernovae precurser that attracts more gas atoms
- ___ d) A small portion of a giant cloud that collapses
- ___ e) A cluster of giant molecular clouds that coalesce to form a solar system
10. Pre–main sequence stars are often surrounded by a protoplanetary disk and powered mainly by
- ___ a) the release of gravitational energy
- ___ b) chemical reactions
- ___ c) the fission of Carbon from Helium
- ___ d) collisions between protoplanets
- ___ e) the fusion of Helium to Carbon
11. Stars that begin with more than 50 solar masses will typically lose _______ while on the main sequence.
- ___ a) 10% of their magnetic field
- ___ b) 10% their mass
- ___ c) 1% their mass
- ___ d) 50% their mass
- ___ e) all of their magnetic field
12. The Hayashi and Henyey tracks refer to how T Tauri of different masses will move
- ___ a) through a cluster as they are born
- ___ b) through an HR diagram as they are born
- ___ c) Two of these are true
- ___ d) through a cluster as they die
- ___ e) through an HR diagram as they die
- ___ a) Decreasing luminosity with no change in temperature
- ___ b) Increasing luminosity with no change in temperature
- ___ c) Increasing temperature with no change in luminosity
- ___ d) Decreasing temperature and increasing luminosity
- ___ e) Decreasing temperature with no change in luminosity
14. When a star with more than 10 solar masses ceases fuse hydrogen to helium, it
- ___ a) it fuses helium to carbon to iron (and other elements), then continues to release more energy by fusing the iron to heavier elements such as uranium.
- ___ b) it fuses helium to carbon and other elements up to iron and then ceases to produce more energy
- ___ c) ceases to convert nuclear energy.
- ___ d) it fuses helium to carbon and then ceases to produce more energy
- ___ e) it fuses elements up to uranium, and continues to produce energy by the fission of uranium.
15. Many supernovae begin as a shock wave in the core that was caused by
- ___ a) electrons being driven into protons to form neutrons
- ___ b) iron fusing into heavier elements such as uranium
- ___ c) the conversion of carbon into diamonds,
- ___ d) all of these processes contribute to the shock wave
- ___ e) carbon and other elements fusing into iron
16. A dying star with more than 1.4 solar masses becomes a ______, and those with more than 5 solar masses becomes a _____
- ___ a) blue giant....red giant
- ___ b) white dwarf....black hole
- ___ c) neutron star....black hole
- ___ d) white dwarf....neutron star
- ___ e) white dwarf...red dwarf
17. According to Wikipedia, a star with over 20 solar masses converts its Hyrogen to Helium in about 8 billion years, but the conversion of Oxygen to heavier elements take about _____
- ___ a) 1 thousand years
- ___ b) 10 billion years
- ___ c) 1 year
- ___ d) 1 million years
- ___ e) 1 billion years
Key to AstroWikipStar_Study-v1s1
1. Why is a star made of plasma?
- + a) it is so hot that electrons are stripped away from the protons
- - b) plasma is always present when there are strong magnetic fields
- - c) the interstellar gas was mostly plasma
- - d) plasma is generic word for "important"
- - e) the intense gravity liquifies the substance, just as red blood cells liquify plasma in the body
2. What is the difference between a constellation and an asterism?
- - a) asterisms are smaller than constellations
- - b) none of these is correct
- + c) constellations represent regions of the sky, like state boundaries on a map of the USA
- - d) asterisms are larger than constellations
- - e) constellations consist of never more than ten stars.
3. Stellar parallax is
- + a) Two of these is correct
- - b) Triangulation to deduce the distance to nearby stars
- - c) Using changes in the angular position of a star to deduce the star’s distance
- - d) Using spectral lines to deduce the distance to nearby stars
- - e) None of these is correct.
4. Giant molecular clouds with sufficient conditions to form a star cluster would have formed them long ago. Any stellar births in the past couple of billions years probably resulted from _____ between clouds.
- - a) photon exchange
- + b) collisions
- - c) None of these is correct.
- - d) ion exchange
- - e) Two of these are correct
5. A starburst galaxy.
- + a) Two of these are correct
- - b) All of these are correct
- - c) usually is a result of collisions between galaxies
- - d) is a region of active stellar birth
- - e) has only dead or dying stars
6. Which of the following expresses Jean's criterion for the collapse of a giant molecular cloud of mass, M, radius, R, and temperature T, and pressure P? (Here ? is some constant)
- - a) P>?MR
- - b) R>?MT
- + c) M>?RT
- - d) T>?RM
- - e) P>?MT
7. Which of the following changes in the properties of a giant molecular cloud might cause it to collapse?
- - a) Decrease mass at fixed temperature and size
- - b) Two of these are correct
- + c) Increase mass at fixed temperature and size
- - d) Increase temperature at fixed mass and size
- - e) Increase size at fixed pressure and mass
8. What happens if you increase the size of a giant molecular cloud while keeping temperature and mass fixed?
- - a) It is more likely to collapse because this will increase the temperature
- - b) It is less likely to collapse because temperature can never be kept fixed
- - c) It is more likely to collapse because larger things have more gravity
- - d) It is equally likely to collapse because size is not part of the Jean's criterion.
- + e) It is less likely to collapse spreading it out weakens the force of gravity
9. What is a Bok globule in the formation of stellar systems?
- - a) A black hole that enters a cloud and triggers the collapse
- - b) A small planet that formed before any stars have formed
- - c) A supernovae precurser that attracts more gas atoms
- + d) A small portion of a giant cloud that collapses
- - e) A cluster of giant molecular clouds that coalesce to form a solar system
10. Pre–main sequence stars are often surrounded by a protoplanetary disk and powered mainly by
- + a) the release of gravitational energy
- - b) chemical reactions
- - c) the fission of Carbon from Helium
- - d) collisions between protoplanets
- - e) the fusion of Helium to Carbon
11. Stars that begin with more than 50 solar masses will typically lose _______ while on the main sequence.
- - a) 10% of their magnetic field
- - b) 10% their mass
- - c) 1% their mass
- + d) 50% their mass
- - e) all of their magnetic field
12. The Hayashi and Henyey tracks refer to how T Tauri of different masses will move
- - a) through a cluster as they are born
- + b) through an HR diagram as they are born
- - c) Two of these are true
- - d) through a cluster as they die
- - e) through an HR diagram as they die
- + a) Decreasing luminosity with no change in temperature
- - b) Increasing luminosity with no change in temperature
- - c) Increasing temperature with no change in luminosity
- - d) Decreasing temperature and increasing luminosity
- - e) Decreasing temperature with no change in luminosity
14. When a star with more than 10 solar masses ceases fuse hydrogen to helium, it
- - a) it fuses helium to carbon to iron (and other elements), then continues to release more energy by fusing the iron to heavier elements such as uranium.
- + b) it fuses helium to carbon and other elements up to iron and then ceases to produce more energy
- - c) ceases to convert nuclear energy.
- - d) it fuses helium to carbon and then ceases to produce more energy
- - e) it fuses elements up to uranium, and continues to produce energy by the fission of uranium.
15. Many supernovae begin as a shock wave in the core that was caused by
- + a) electrons being driven into protons to form neutrons
- - b) iron fusing into heavier elements such as uranium
- - c) the conversion of carbon into diamonds,
- - d) all of these processes contribute to the shock wave
- - e) carbon and other elements fusing into iron
16. A dying star with more than 1.4 solar masses becomes a ______, and those with more than 5 solar masses becomes a _____
- - a) blue giant....red giant
- - b) white dwarf....black hole
- + c) neutron star....black hole
- - d) white dwarf....neutron star
- - e) white dwarf...red dwarf
17. According to Wikipedia, a star with over 20 solar masses converts its Hyrogen to Helium in about 8 billion years, but the conversion of Oxygen to heavier elements take about _____
- - a) 1 thousand years
- - b) 10 billion years
- + c) 1 year
- - d) 1 million years
- - e) 1 billion years
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