## Assignments

Assignments are due at beginning of class.

- Assignment 1, Sept 16 to Sept 23: Problems 1.1, 1.2, 1.10, 1.17, 1.18
- Assignment 2: Sept 23 to Sept 30: 1.8, 2.6, 2.8, 2.10 and 2.11.
- Assignment 3: Due Monday October 7 at the beginning of class. Problems 3.5, 3.6, 3.7 and 3.8. Updated hint for 3.5: for deriving the equations, start with eq 3.12. in the first step, the sum over all particle masses (small m) will equal the total masses of each kind of particles. The trick is to express everything in m_H (how many m_H in an m_He? How many in m_m?). In the case of completely ionized gas (deriving 3.9), keep in mind that even though electrons contribute negligibly to mass, they do contribute to NUMBER of particles! So make sure to include them here, e.g. N=N_H+N{e,H} + ....etc (whereN_{e,H}=number of electrons that come from the hydrogen atoms) (whereas above, you would only include N_H, N_He and N_m in your total N).

For 3.7, equation 3.22 is helpful (didn't go into details in class).

For 3.8, the means of interaction is given. example 3.5 might be helpful here... - Assignment 4: Handed out Oct 9, Deadline Thursday Oct 17. Problems 4.4, 4.6, 4.9, 5.1, and 5.6. Problem 4.4 builds upon 4.3, so I have posted the answers to 4.3 here (link removed).
- Assignment 5: Due Monday October 28 - EXTENDED TWO DAYS, until Wednesday October 30! Problems 5.9, 5.14, 5.15, 6.2, 6.3. Hint for 5.9: See ex 5.4. Use one of the special cases of the Planck law (verify that this can be done). 5.15: see example 5.5, table G.11. (more hints may materialize here...)
- Assignment 6: Handed out (via email) on Tuesday Oct 29, Due Thursday November 7. Problems 6.5, 7.2, 7.5, 7.12.
- Assignment 7: problems 8.1, 8.3, 8.5, 8.6 and 8.8. Handed out Nov 7, Due on Thursday Nov 14.
**EXTENDED TO MONDAY Nov 18!** - Final assignment 8: Given out on Monday Nov 18. Deadline Thursday Nov 28.Four problems: 8.13, 8.14 (good idea to get done asap), 9.9 and 9.10 (we haven't gotten there in lectures yet, so save these for a little while). Very useful problems all of them! :)
**NEW:**Hints**8.13:**The problem states how the rising and falling part of the spectrum look like. Compare to eq 8.41 and 8.42...**8.14:**You'll notice that you need to find T_B. You have f_nu_max, which will get you to I_nu_max. Check where your frequency falls - in R-J limit or Wien-limit? (h*nu/kT<<1 or >>1? ok, you don't have T, but you can still make a fair estimate with the other parameters..). Then you should end up with a rather substantial T_B (but not exceeding the temp of "Compton catastrophe"...)

*own*solutions, in your*own*words, that show**that you understand them well!***clearly***By "clearly" I mean describe the steps you take properly. Don't assume your TA is a mindreader... If you show clearly your thoughts and strategies you're likely to get points even though the answer might not be exact. (and vice versa.....)****NEW:**Answers and hints to assignments are located in the following locations (links removed):**Assignments 1 and 2****Assignments 3 and 4****Assignments 5 and 6****Assignments 7 and 8**