Information for the Written Final

Location	MHP 106
Date & Time	Tuesday, April 18, 2000 from 5 - 6:30pm

• About the grades: all grades in lab are raw scores only; these scores will be scaled according to the rest of the labs to determine your final score (and hence, final grade).
• As for the following notes, please remember that all these notes are just random ramblings of things that stuck out at me. There are probably many points that I forgot to flag but that will probably be on the exam... so remember that the best review is the one you do on your own.
• In that vein, I'll end this now with a quote that I read in my freshman year in our catalogue of classes. The quote was from a student (a big, bad senior, if I remember correctly) and went something like this: "Our professor is very thorough; whatever he doesn't cover in lectures, discussions, or homeworks, he'll be sure to cover on the exam". With that in mind...
  Best of Luck!!!
  ...because you'll need it...

• What's it going to be like?
• What should I know?
• What should I bring?

• The written exam has approximately 7-8 questions. It is not comprehensive and only covers labs 6-10!
• Like the midterm, the final exam is very similar to the previous written exams... your best preparation for it is, without a doubt, reviewing the old exams. The old exams are available at: http://physics1.usc.edu/Undergraduate/Labs/135b/. As usual, pay particular attention to the exams going back to Spring 1998 (look over the midterms in previous terms, too, as there's a potential switching around of the order of the labs among the different terms).
• The exam is closed book but most important formulas will be given (but not the trivial ones like V=IR!).
• The exam is scheduled for 4/18/2000 and all of my sections will be in MHP 106 (the other sections are going to be in MRF 340).
• The lab written exam is setup as follows:
  1. You will have 1 ¹/₂ hours to finish approximately 7-8 questions.
  2. There will definitely be questions on:
     • Bioelectric measurements and what they meant
     • Lenses, mirrors, and total internal reflection, oh my!
     • The human eye and the various defects (and corrections)
     • Diffraction, interference, and intensity of light
     • Force transducers and how they work
     In addition, you'll be required to know how to manipulate the various equations (most will be given to you), what different parts of the equations mean, how to interpret linear, semi-log, and log graphs, etc.
  3. Emphasis on computation... although there is some theory on this exam, for the most part, be prepared to use techniques you know in new situations. On the whole, this exam is probably more straight-forward than the midterm... but be sure to study hard for it since the mean might be a lot higher this time around for the whole class.

• Bioelectric Measurements -- Lab 6
  • Review the different kinds of bioelectric measurements (eeg, ekg, etc.).
  • Know the definition of the reflex time (it's in the objective and in the lab notes link to the left!).
  • When you measured the reflexes, what did the graphs look like? How did you interpret them? Give your lab answer book a look for this one.
  • How did you make the different measurements? How did you figure out averages, etc.?
  • Did changing various parameters affect the reflex time? E.g., how did you answer the questions on p. 78? Review those answers and make you understand them.
• Geometric Optics -- Lab 7
  • How is geometric optics different from physical optics (lab 9)?
  • Make sure you understand the law of reflection & refraction. Remember that snell's law (n_isinq_i = n_rsinq_r, where the index of refraction is n = c/v; see the lab notes) applies at the interface between two surfaces of different indices of refraction.
  • Know the difference between concave and convex mirrors (Figure 2 on p. 82).
  • How does the mirror equation relate to the lens equation (hint, see item 1 in the lab notes)?
  • When is d_i positive or negative for a mirror? How about for a lens? For this, please be sure to memorize the table I made for lab 8 (the sign conventions table in item 1)!
  • What is the critical angle in total internal reflection? For that matter, what is total internal reflection? If you haven't been to the link in the lab notes before, take a moment to go check this out now. Make very sure you understand what you did in Section 4.5 on p. 86!
  • Finally, how did the lenses behave in Section 4.6? How did you setup the multiple lens system in Section 4.7? Make sure you understand how lenses work in combination with each other and how focal lengths, etc. are affected by lenses in combination.
  • A nice (but extra) review of the material covered in labs 7 & 8 can be found by quickly glancing over this site
• Lenses and the Human Eye -- Lab 8
  • The most important item for this lab is the sign conventions table in the lab notes. Make sure you memorize this sucker and actually understand all the the entries (especially the entries for lenses).
  • Review the lens equation again; when are f or d_i negative? How did you calculate the magnification of an image (2 ways)? When is an image inverted or upright? Refer to the table if you get confused about these.
  • What kind of images do positive (converging) and negative (diverging) lenses create? Why did you have to go through the combination lens method in Section 4.3 (pp. 94-95)? How is the power of a lens (the diopter rating) related to the focal length?
  • For the human eye, what purpose does the vitreous humour serve (hint: think of the effect that adding the water had on the focal length of your Cenco eye (Q. 4.4.3 on p. 96); remember that d_i remains fixed here)?
  • What kind of defects did we study in this lab? What caused them? How did we fix them? For these, refer to the Visual defects and their corrections section of Item 1 of the lab notes).
• Physical Optics -- Lab 9
  • The main stuff in this lab was single-slit and double-slit diffraction. Make sure you understand the difference between the two and how the n's are numbered in each (review Item 1 in the lab notes in detail).
  • The two main equations we used in this lab were Eq 6 & Eq 13. What is the significance of each of the terms in them? Make sure you understand how to use these 2 equations and WHEN to use one or the other (e.g., if you were dealing with a single-slit problem, which equation would you use? What does the n stand for? What about the y_n-y_o term?).
  • What is the inverse square law for the intensity of electromagnetic radiation? How does the force vary with distance? See Section 4.4 on p. 109 and pay particular attention to how you filled out the data table on p. 110 (e.g., how did you calculate the ideal voltage at each distance? how were the ideal and theoretical voltages related? why?).
  • Also, make sure you understand Section 4.5 on p. 111 and especially the questions that you answered on that page (in particular, review Questions 4.5.1 to 4.5.6).
  • An absolutely beautiful review of diffraction of light can be found at the Microscopy Primer. They also have a great tutorial on diffraction and resolution in microscopes and the human eye. Take a moment to give them a look, especially if your book seemed confusing on this topic.
• Transducers -- Lab 10
  • Know how the speaker works (p. 113). Why does pressing in on the speaker cone (and holding it in) result in the signal disappearing (see the first 2 paragraphs on p. 114)? How is the strain gauge different from the speaker (i.e., what kind of forces do each respond best to)?
  • Be very sure you completely understand the force transducer calibration curve (Fig. 4 on p. 114). Is it linear or non-linear? Why? When does it start to deviate? What are the implications of this deviation? Read pp. 114-115 for this.
  • For this one, I'd really make sure I read and understood pp. 113-115 (don't worry too much about the workings of the Wheatstone bridge on p. 115).
• You don't have to worry so much abouth the inner workings or mechanisms of most of the stuff; just understand what they do. Make very sure you review all the formulas and understand what is what in the main ones enough to be able to use them (e.g., what is n in a double-slit as opposed to a single-slit? what does y_n represent? what is n for the second dark spot in a single slit diffraction pattern as opposed to a double-slit (see the quiz for lab 9 for this)?). The important thing is to know what all the main formulas mean and how to use them.
• Just like on the midterm, remember to keep track of units during any calculations; perform unit conversions with care and keep an eye out for order of magnitude errors (e.g., if you're figuring out the focal length, make sure you convert everything to meters instead of carrying cm's or mm's and ending up with a funky answer). Be VERY sure to show all your work.
• Finally, work quickly but carefully... and the neater the work, the easier it is on the grader. If you're unsure of the answer but are sure of your reasoning leading up to the answer, go ahead and explain what you were trying to do or what you know. Often, that'll get you at least some partial credit (if your reasoning is correct, that is!). Always try to write down the correct units at all stages and check your intermediate results to make sure it makes sense. And, most importantly, remember to take a deep breath and relax! In the big scheme of things, this really isn't all that much... just your whole, entire future, is all...

1. Your calculator (don't leave home without it!)
2. Ruler or straight-edge
3. A pen or pencil (depending on how masochistic you are...)