# Astronomy 12 - Spring 1999 (S.T. Myers)

## Final Exam Review

Last update: April 26, 1999

Test Format:

This exam will concentrate on the material covered in lecture, reading, and homework since the second midterm exam, though there will be questions covering the earlier material (the final is cumulative). Therefore, it is important that you review previous problems also.

I am not asking you to memorize a bunch of equations and things, so the tests (including the final) will be open-note. Because the text does things in a different, and often confusing, way, you may not use your textbook during the exam (its not open-book). As before, you will be provided with an equation sheet, and you may also bring several sheets of your own notes. Please do not use the book or bring a binder will my photocopied notes.

Again, the bulk of the exam (>75%) will be quantitative problems like in the homework and extra credit problem set. The remaining fraction of the exam will be qualitative. In Astro12, we will be talking about such a wide range of phenomena and measurements related to them that it will be critical to make sure we all know what we are talking about. Therefore, as part of each midterm (and the final) there will be some short answer questions where you will be asked to give a couple sentences explaining some topic (see the examples below).

The problems and questions below are for teaching and review purposes only. Do not hand in the answers for these, as you will not receive any credit!

Remember to bring a calculator.

I hope that these help to focus your studies...

Review Problems from the Textbook Chapters 18-26:

Note that this course is problem-based and just reading the textbook and notes will not train you sufficiently to be able to really use the material in problem solving situations (like the exam). Be sure to re-work your old homework problems and the Sample Problem Set for practice.

Some of the questions in the book can be used for review. The answers are not given, but you should have a pretty good idea if you know how to do a problem or not! You should at least have an idea on how to tackle problems like these.

1. Chapter 18: (p.378-379) Problems 1, 3, 6, 9, 10, 12, 16, 17.

2. Chapter 19: (p.391-392) Problems 1, 6, 7, 8, 10, 13, 15, 16, 17.

3. Chapter 20: (p.409-411) Problems 2, 3, 4, 5, 7, 10, 13, 17.

4. Chapter 21: (p.431-432) Problems 1, 3, 5, 6, 7, 9, 10, 11, 12.

5. Chapter 22: (p.444-445) Problems 1, 3, 4, 5, 8, 11, 12.

6. Chapter 23: (p.463-464) Problems 1, 3, 5, 6, 7, 10, 11, 12, 13.

7. Chapter 24: (p.486-487) Problems 3, 4, 5, 6, 8, 9, 12, 13, 14, 17, 19, 20.

8. Chapter 25: (p.501-502) Problems 1, 2, 3, 4, 5, 6, 7, 12

9. Chapter 26: (p.515) Problems 1, 2, 3, 4, 5, 6.

This is a list of short topical questions you should be able to answer. Some of these will be on the exam. I am looking for a sentence or two, and these are qualitative, not quantitative (read as: don't memorize numbers, just know the cartoon pictures). The key topics are in italics. It is also a good idea to look through the questions posed in the Investigations section of the on-line Lecture Notes for each lecture.

The following questions are for the topics not covered in the midterms. Again, since the final is cumulative, you can expect at least one and probably more questions from previous material, so look over the midterm reviews.

1. What are Cepheids, and how are they used as distance indicators?

2. How do we determine the age of a cluster of stars?

3. What is differential rotation, and how does it relate to the measured velicities of stars in the disk of our galaxy?

4. What is the primary way we have of determining the composition of the atmospheres of stars and the interstellar gas, molecular and dust clouds?

5. What is the difference between the free-fall time and the sound-crossing time for a gas cloud, pulsating star, or forming planet?

6. How do the conservation of angular momentum and conservation of magnetic flux affect star formation?

7. What is the Hubble sequence of galaxies, and what are the properties of the three main types of galaxies?

8. What evidence is there for dark matter in galaxies?

9. What is a luminosity function? How is it related to the mass function and the mass-to-light ratio?

10. What are the Tully-Fisher relation and the Faber-Jackson relation and what are they used for?

11. What is the evidence for the expansion of the Universe, what is its interpretation, and what is the Hubble constant?

12. What is a radio galaxy? What is a quasar? What is the leading model for the source of their power?

13. Why is the likelihood of galaxies interacting with each other much greater than the likelihood of interaction between any two stars in a galaxy? What do galaxy interactions do?

14. What is gravitational lensing?

15. What is the peculiar velocity of a galaxy, and what do we mean by the Great Attractor?

16. What is the cosmological principle? What do we mean when we refer to the Big Bang?

17. What are closed, open and flat universes, and what are the eventual fates of these cosmologies?

18. What are the meanings of the following cosmological parameters: H0, q0, k, and 0?

19. What is the cosmological constant, how can it make a static universe? What is inflation, what causes it, and what is it good for?

20. What is the cosmic microwave background, and what is its significance in cosmology?

21. What are the following notable stages in the early universe: last scattering, matter-radiation equality, nucleosynthesis, electron-positron production, neutrino decoupling, proton-antiproton production, electro-weak unification, grand unification, Planck era?

22. What is the steady-state model, and what evidence is used to argue against it?

23. What is the cosmological constant?

24. What three cosmological problems does the model of inflation solve, and how?

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myers@dept.physics.upenn.edu Steven T. Myers