PHYS 1412: Quiz - The Stars

Second quiz, topic 'Stars.' 10 questions per quiz. Below are all the unique questions of my three attempts for the 100. Questions without marked answers are ones I got wrong and didn't come up to try again.

You observe a star in the disk of the Milky Way, and you want to plot the star on an H-R diagram. You will need to determine all of the following, except the

1. spectral type of the star.
2. distance to the star.
3. apparent brightness of the star in our sky.
4. rotation rate of the star.

The apparent brightness of a star depends only on its luminosity.

1. True
2. False

Two stars both lie on the main sequence. Star X is spectral type A, while Star y is spectral type G. Therefore, Star X is more massive than Star Y.

1. True
2. False

Which of the following terms is given to a pair of stars that appear to change positions in the sky, indicating that they are orbiting one another?

1. visual binary
2. eclipsing binary
3. spectroscopic binary
4. double star
5. None of the above.

What are the standard units for apparent brightness?

1. watts
2. joules
3. Newtons
4. watts per second
5. watts per square meter

Which process leads to the production of carbon?

1. H fusion by the proton-proton chain
2. H fusion by the CNO cycle
3. helium fusion
4. matter-antimatter annihilation
5. gravitational contraction

Which two energy sources can help a star maintain its internal thermal pressure?

1. nuclear fusion and gravitational contraction
2. nuclear fission and gravitational contraction
3. nuclear fusion and nuclear fission
4. chemical reactions and gravitational contraction
5. nuclear fusion and chemical reactions

What happens when a star exhausts its core hydrogen supply?

1. Its core contracts, but its outer layers expand and the star becomes bigger and brighter.
2. It contracts, becoming smaller and dimmer.
3. It contracts, becoming hotter and brighter.
4. It expands, becoming bigger but dimmer.
5. Its core contracts, but its outer layers expand and the star becomes bigger but cooler and therefore remains at the same brightness.

What is the CNO cycle?

1. the process by which helium is fused into carbon, nitrogen, and oxygen
2. the process by which carbon is fused into nitrogen and oxygen
3. a type of hydrogen fusion that uses carbon, nitrogen, and oxygen atoms as catalysts
4. the period of a massive star's life when carbon, nitrogen, and oxygen are fusing in different shells outside the core
5. the period of a low-mass star's life when it can no longer fuse carbon, nitrogen, and oxygen in its core

What is the range of star masses for high-mass stars?

1. between 500 and 1,000 solar masses
2. between 200 and 500 solar masses
3. between 8 and 100 solar masses
4. between 2 and 10 solar masses
5. between 2 and 5 solar masses

On a Hertzsprung-Russell diagram, where would we find stars that are cool and luminous?

1. upper right
2. lower right
3. upper left
4. lower left

On a Hertzsprung-Russell diagram, where would we find stars that have the largest radii?

1. upper right
2. lower right
3. upper left
4. lower left

Which of the following terms is given to a pair of stars that we can determine are orbiting each other only by measuring their periodic Doppler shifts?

1. visual binary
2. eclipsing binary
3. spectroscopic binary
4. double star
5. None of the above.

Which of the following persons reorganized the spectral classification scheme into the one we use today and personally classified over 400,000 stars?

1. Annie Jump Cannon
2. Williamina Fleming
3. Cecilia Payne-Gaposchkin
4. Henry Draper
5. Edward Pickering

If it could possibly be engineered, which method of energy generation would be the most efficient possible energy source for interstellar travel?

1. H fusion by the proton-proton chain
2. H fusion by the CNO cycle
3. helium fusion
4. matter-antimatter annihilation
5. gravitational contraction

The most massive stars generate energy at the end of their lives by fusing iron in their cores.

1. True
2. False

All of the following are involved in carrying energy outward from a star's core except

1. convection.
2. radiative diffusion.
3. conduction.
4. neutrinos.

Convection never occurs in the Core of any type of star.

1. True
2. False

Stars of lower mass have deeper convection zones outside their cores than stars of higher mass.

1. True
2. False

Two stars have the same spectral type. Star X is in luminosity class III, while Star y is in luminosity class V. Therefore, Star X is larger in radius than Star Y.

1. True
2. False

Which of the following statements about an open cluster is true?

1. All stars in the cluster are approximately the same color.
2. All stars in the cluster are approximately the same age.
3. All stars in the cluster have approximately the same mass.
4. All stars in the cluster will evolve similarly.
5. There is an approximately equal number of all types of stars in the cluster.

If the distance between us and a star is doubled, with everything else remaining the same, the luminosity

1. is decreased by a factor of four, and the apparent brightness is decreased by a factor of four.
2. is decreased by a factor of two, and the apparent brightness is decreased bya factor of two.
3. remains the same, but the apparent brightness is decreased bya factor of two.
4. the luminosity remains the same, but the apparent brightness is decreased by a factor of four.
5. is decreased by a factor of four, but the apparent brightness remains the same.

Suppose the star Betelgeuse (the upper left shoulder of Orion) were to become a supernova tomorrow (as seen here on Earth). Wha t would it look like to the naked eye?

1. Because the supernova event destroys the star, Betelgeuse would suddenly disappear from view.
2. We'd see a cloud of gas expanding away from the position where Betelgeuse used to be. Over a period of a few weeks, this cloud would fill our entire sky.
3. Betelgeuse would remain a dot of light but would suddenly become so bright that, for a few weeks, we'd be able to see this dot in the daytime.
4. Betelgeuse would suddenly appear to grow larger in size, soon reaching the size of the full moon. It would also be about as bright as the full moon.

Although some photographs show what looks like jets of material near many young stars, we now know that these "jets" actually represent gas from the surrounding nebula that is falling onto the stars.

1. True
2. False

What happens after a helium flash?

1. The core quickly heats up and expands.
2. The star breaks apart in a violent explosion.
3. The core suddenly contracts.
4. The core stops fusing helium.
5. The star starts to fuse helium in a shell outside the core.

What is a carbon star?

1. a red giant star whose atmosphere becomes carbon-rich through convection from the core
2. a star that fuses carbon in its core
3. another name for a white dwarf, a remnant of a star made mainly of carbon
4. a star that produces carbon by fusion in its atmosphere
5. a star that is made at least 50% of carbon