Announcements

Instructor

Professor William Loinaz
Office: 223 Merrill Science Center
Phone: (413) 542-7968
email: waloinaz@amherst.edu
Office Hours: Monday 11-12 am, Tuesday 10-11:30 am, Wednesday 1-2 pm, or by appointment. You're also welcome to drop by my office. If I'm in and free I'm happy to meet with you, but it's not so often during the day that I'm in and I'm free.

Grader: Abby Ouimet

Course Information

Course Description:

The first part of the course deals with simple thermal phenomena and an introduction to statistical mechanics and thermodynamics. This is the study of systems with huge numbers of particles, each of which moves randomly. We'll find that by ignoring the detailed random motions of particles and looking at such systems in terms of only macroscopic observables we can come to very general and powerful conclusions about their behaviors. The latter part of the course is the study of linear waves, a class of coherent motions commonly present in systems of large numbers of particles (e.g. a big metal rod). Our approach to this problem will be to neglect the discreteness of the system and instead approximate the many particles by a continuous field, analogous to the electromagnetic field from Physics 33. As a result, we will be able to study both many sorts of waves in various media and waves, including electromagnetic waves. The same principles will apply in quantum mechanics as well, where matter itself is treated as a wave (although you'll have to wait until you take Physics 35 to see this).

The general characteristics of wave motion will be approached through the wave equation and the solution to the boundary value problem. Subsequent discussion cover energy relationships in waves, diffraction, interference, reflection, refraction and polarization.

There are a pair of "outsider" topics as well. One is geometrical (ray) optics, which is really a consequence of the behavior of electromagnetic waves but which not be treated in the same fashion. Another is operational amplifiers, which will be useful in Physics 35 but which have nothing to do with anything else in the course.

Throughout the course, new mathematical techniques including probability and combinatorics, Fourier analysis and matrix algebra will be introduced as needed. Mathematica and/or Calculation Center may be introduced to broaden the range of problems you'll be able to tackle.

Schedule

• Class: MWF 10-10:50, T 2-2:50 (Merrill 211)
• Lab: W 2-5 (Merrill 217)
• Problem Session (informal): Monday night at 8 pm, physics student lounge.
• The fourth hour, Thursday 4:30-5:20, is subject to change. Since I have had requests to consider different times, on the first day of class I'll poll to see if there is a different time that is collectively agreeable. If I can find no such time, we will retain the current fourth hour by default.

Prerequisites

Course requirements

• Attendance: Come to class. Lots of stuff will happen there and you wouldn't want to miss out. It's your affair how you allocate your time and I won't explicitly penalize you for being absent, but if you're going to be absent please do me the courtesy of letting me know in advance, if possible. It's a small class--I'll notice if you're not there. If you arrive late, please enter quietly at the back of the classroom. Obviously it will be your responsibility to find out what happened in the class you missed. Also, you must attend all of the labs.
• Homework: I'll assign weekly problem sets, due Monday @ 11:59 pm. You may leave your homework in my mailbox near the physics department office, or of course you may give it to me personally (please do NOT leave it in the box beside my office or stick it under my door). Homework submitted late without prior arrangement will receive a 50% penalty if submitted within three days of the due date (i.e. Thursday at 11:59 pm), and will not be accepted after that. If you've got a compelling reason why you need an extension, come talk to me in advance. I will not grant a homework extension without penalty if you ask for it on the day the homework is due, so don't ask for one. [If you need such a last-minute or post-facto extension due to extenuating circumstances (e.g. death in the family, sudden illness, travel problem), you'll need to have the Dean of Students or your Class Dean formally make such a request to me and suggest a rescheduled due date. You should also take this route if you need an extension but you don't want to tell me why (say, it's for personal or legal reasons). If you explain your reason to a Dean and the Dean tells me it's OK, that's good enough for me.] In general, though, life will be easier for you and for me if you get into the habit of doing your best to finish the problem set on time and handing in as much as you've been able to complete by the deadline.

  I can't emphasize enough the importance of working the homework. In some of your classes homework is primarily evaluative; the point is for you to demonstrate what you've learned from the readings and lectures. In this course, and in most physics courses, the homeworks are primarily instructional; you learn physics primarily by doing the assignments. You must work the problems, think about the results, and understand any mistakes you've made if you wish to attain the type of understanding of the subject required of a working physicist. I (or a grader) will grade the problems, and I'll hand out solutions. I encourage you to read the solutions and understand any mistakes immediately. If it doesn't make sense, ask me about it right away---don't wait until right before an exam.

• Labs: A weekly lab will be held in Merrill 217, Wednesday 2-5. Attendance at all labs is mandatory; if you must miss a lab for some compelling reason, please see me well in advance so that we can schedule an alternative time for you to work the lab. I'll hand out a lab manual at the beginning of the semester. Please read the relevant portions of the lab manual before coming to lab. Some labs will be graded by exit inteviews, others by formal lab writeups (listed respectively as EI or formal in the last column of the lecture/lab schedule below). Please bring to lab a bound lab notebook (any type: spiral, etc.) that can be used solely for Physics 34 (we will want to collect your lab notebooks at some point during the semester). I also recommend you bring a floppy disk for saving data, etc.

  The formal lab writeups are due one week from the day the lab was performed, unless otherwise noted. For the first lab report I'll permit a rewrite. Late labs (and rewrites) will be penalized 10% per day late (including weekends). In any case, each lab not performed or lab report not submitted will automatically cost at least a full letter grade in the final course grade.

• Exams: There will be two mid-term exams and a final, and these will serve as the primary evaluative mechanisms for the course. The exams will be closed-book, and all course material (lectures, labs, handouts, text readings and homeworks) will be fair game for the exam. I'll give you relevant formulae, so the exams will be not be memorization exercises. I tend to have some mix of short-paragraph written questions and problems. I tend to like problems that ask that you derive results utilizing key derivations from class, then use the result to do something new.

  I'd like to schedule the mid-term exams outside normal class hours Wed. March 6, 7 pm, and Wed. April 17, 7 pm.

If you'll have a conflict with these days, let me know immediately. I am usually willing bend the exam start time a little if you have some conflict, but I expect everyone to take the exams on the same day, and around the same time.
• Extensions: In the interest of fairness I will hold fast to the deadlines and policies above. In particular, I won't grant extensions to homeworks on the day they're due, and I won't reschedule the exam for an individual to a different day from the rest of the class. Should circumstances render such rescheduling unavoidable, you'll need to have the Dean of Students or your Class Dean contact me with a formal request for an extension and a suggested rescheduled time. Such matters should be taken care of before the exam if at all possible. If the matter is personal or confidential, the Deans need not provide me with any particulars, only their opinion that the rescheduling is reasonable.

  The College requires that all written work for a course except for a final be submitted by 5 pm on the last day of classes. The physics department takes this deadline seriously. After that day/time, no homework or lab reports will be accepted, nor will I conduct exit interviews for labs.

Statement of Intellectual Responsibility:

• I strongly encourage you to discuss the homework problems and learn the labs with your classmates---discussing and debating the concepts and procedures is a very effective way to learn. However, the final write-ups of your assignments or lab reports should be your own. For example, the copying homework solutions in part or in whole from other students (current or prior) or from other sources (commercial or otherwise) is unacceptable. I don't mind if you use other texts to learn from, and if the answer to a homework problem is worked as a example in some other text you may utilize it (although you should first try to solve it on your own as best you can). But in that case you should make an explicit reference to the source in your homework, and of course you still need to explain the solution to the problem in your own words. It goes without saying, but I'll say it anyway: tests are written without help.
• In the lab, lab partners are expected to share equally in the collection of data. However, each student must keep a separate record of the data and do all calculations independently. Lab writeups should be done independently, although you may discuss the data and analysis with other members of the class. Copying or paraphrasing any part of another lab writeup is obviously inappropriate. In addition, we wish to emphasize that intellectual responsibility in lab work extends beyond simply not copying someone else's work to include the notion of "respect for the data". By this we mean that you should not alter, "fudge" or make up data just to have your results agree with some predetermined notions. It is always best to simply state that your results did not turn out as anticipated and try to understand the discrepancy between your expectation and the data. You should never erase data which appear to be wrong. It is perfectly legitimate to state that you are going to ignore some data in your final analysis if you have a justifiable reason to suspect a particular observation or calculation.
• If you have any questions about what is or is not acceptable under this policy, please ask us. In all cases, the spirit of the Statement of Intellectual responsibility will take precedent over legalistic convolutions of the text.

Grading:

• Homework: 20%
• Lab: 15%. (However, all labs, lab reports and exit interview must be completed to instructor's satisfaction or large automatic penalties will apply.)
• First Midterm: 20%
• Second Midterm: 20%
• Final: 25%

Textbooks:

Required (should be available at the Jeffrey Amherst bookstore):

• An Introduction to Thermal Physics (ISBN: 0201380277)(hardcover), by Daniel V. Schroeder
  [This book is about the right level, although it contains more material that we'll cover (it's designed for a semester-long course).]
• Fundamentals of Physics (Sixth Edition): Part 4 (contains Chaps. 34-48) (ISBN: 0-471-36039-2)(softcover), by Halliday, Resnick & Walker
  [This book is a bit lower level than I'd like--it's often used in first-year courses-- but it will provide a coverage of geometrical optics that lectures will build on.]
• Wave Phenomena (ISBN: 0-486-65818-X)(softcover), by Dudley Towne (an Amherst College Professor Emeritus)
  [The level is about right, although the book contains more material than we'll cover, is not very flexible in the ordering of topics, and is a bit old-fashioned. Good value for the price, though.]
• In addition, please obtain a lab notebook dedicated to Physics 34 labs (i.e. one that I can collect and keep for as long as I like). Bring it to lab on Wednesday.

• Six Ideas that Shaped Physics: Some Processes are Irreversible, by Thomas Moore [One of the texts used last year in Physics 34. It was unpopular with the class, although I liked it.]
• Lectures in Physics, Chap. 39-46 (vol. 1), R. P. Feynman
• Understanding Thermodynamics, H. C. van Ness
• Thermodynamics, Enrico Fermi [a small book by one of the masters]
• Thermodynamics and Heat Power, Granet & Bluestein [engineering applications]
• Thermal Physics, C. Kittel and H. Kroemer [advanced text occasionally used in Physics 75]

• Lectures in Physics, (vol. 2), Richard P. Feynman [Feynman's insights are always unique and worthwhile.]
• Optics (4th ed.), Eugene Hecht [Talks about waves, but obviously with a focus on electromagnetic waves.]
• An Introduction to Optics (2nd. ed.), Pedrotti and Pedrotti
• Vibrations and Waves, French
• Electricity and Magnetism, Chap. 9, E. Purcell [The text used in Physics 33 last semester.]
• Waves, F. Crawford [Develops waves from discrete mechanics. Lots of nice at-home experiments. Out of print.]
• The Physics of Waves, Howard Georgi [Similar to Crawford in approach, but with more sophisticated mathematics.]
• Classical Dynamics of particles and systems, Marion and Thorton. Chap 13 covers waves, Chap 3 covers Fourier series. [A succinct treatment of the wave equation. The text has been used in Physics 42.]
• Physics of Waves, William C. Elmore and Mark A. Heald [One of the standards at this level. I haven't used the book much myself, but it looks good.]
• Optics (Schaum's Outline Series), Eugene Hecht [Worked examples are always nice for studying.]

• Experimentation: An Introduction to Measurement Theory and Experiment Design (3rd. ed.), D.C. Baird [A good overview of general techniques useful in lab work.]
• An Introduction to Error Analysis, John R. Taylor [A good introduction to error analysis of the sort that is useful in our lab work.]

• QED, R. P. Feynman [an introduction to the quantum theory of light]
• Mathematical Methods for Physicists, Arfken [a mathematical physics book that has the details about Fourier series and Fourier transforms that we gloss over in class]
• Mathematical Methods in the Physical Sciences (2nd ed.), Mary L. Boas [another mathematical physics book that has Fourier analysis stuff. at a lower level than Arfken. very popular around here.]
• Mathematical Handbook (Schaum's Outline Series), Murray R. Spiegel [a convenient compendium of useful mathematical formulae, including integrals and special functions at a low, low price. You should buy a copy---you'll use it through your entire physics career.]
• Fourier Analysis (Schaum's Ouline Series), Murray R. Spiegel [lots of worked examples of Fourier series and Fourier transforms, if you want more practice]

Other Comments:

Lecture/Lab Schedule

Week	Notes	Hmwk	Lab
1. January 28	Intro thermo: zeroth and first laws Jan 28: Administrative stuff / Course overview / Big picture of thermal physics. Why does time flow forward? [Handouts: Intro pages, info sheet, first lab] Jan 29: What is temperature? Paradigmatic thermal process. Thermoscopes, temperature, thermal equilibrium and the zeroth law of thermo. Constant volume gas thermoscope. Jan 30: Thermometers. How is energy stored in matter? Connection between energy and temperature. Ideal gases: ideal gas law, kinetic theory model of ideal gas. [Handout: Romer AJP article on temperature scales] Feb 1: How well does our ideal gas model work? Specific heat prediction and comparison to experiment. Equipartition theorem. Role of quantum mechanics in turning off degrees of freedom.	Read Schroeder, Chap. 1 (you may omit section 1.7) Problems from Schroeder, Chap. 1: 8, 16, 20, 22, 27, 31, 34, 38, 39, 40.	Lab 1: Ideal Gas Thermometry	EI
2. February 4	Finish First Law, start Second Feb 4: More on quantum mechanics and mechanical degrees of freedom. Heat and Work. Definitions. Types of work. Calculating work. PV diagrams and constrained processes. Quasistatic processes. [Handout: second lab; "Hot", by Nan Kim-Paik] Feb 5: Calculating heat and work for some interesting processes. Heat capacities. Latent heat. Feb 6: Second law: microscopics. Microstates, macrostates, and multiplicity. Two state system: model, counting states, probabilities, calculating multiplicities for macrostates. Feb 8: Stirling's approximation. Simplifying the multiplicity function. Large and very large numbers. Sharpness of the multiplicity function and the probability distribution. Sharp probability distribution implies well-defined average physical properties. [Handout: Walker's "Amateur Scientist" article on the Leidenfrost effect.]	Read Schroeder, Chap. 2 Problems from Schroeder: Chap 1: 43, 46, 55; Chap 2: 4, 8, 18, 19, 22, 24.	Lab 2: Latent heat of liquid nitrogen	Formal
3. February 11	Entropy and the Second Law Feb 11: Fundamental assumption combined with sharp multiplicity functions implies macroscopic regularity. Einstein Model: model, equipartition theorem results, and basic quantum mechanics of harmonic oscillators. Calculating multiplicity function. [Handout: Calculating the multiplicity of an Einstein solid using generating functions] Feb 12: Irreversibility of heat flow using the Einstein model: multiplicity for systems in thermal contact. How sharp is the peak? Sharp peak (with most of the weight) implies irreversibility. Ideal Gases: multiplicity. [Handouts: (1) Lab 3--Measuring ratio of specific heats, (2) Complex Numbers and AC Circuits] Feb 13: Finish the multiplicity of ideal gas. Mulitiplicity for gases in thermal and mechanical contact. Sharp peak means macroscopic regularity, which means well-defined equilibrium temperature and pressure. Define entropy. Second law of thermodynamics: entropy tends to increase. [Handouts: (1) Complex Numbers and the meaning of exp[ix], (2) Complex Numbers and AC circuits.] Feb 15: Finish up the Second Law. Complex Numbers. [Handouts: (1) Input and output impedance and Thevenin's theorem, (2) and (3) Exerpts on op-amps from Horowitz and Hill, (4) Exerpt on op-amps from Diefenderfer.]	From Schroeder, Chapter 2: 2.25, 2.26, 2.30, 2.32, 2.34, 2.38, 2.40, 2.42.	Lab 3: Measurement of Cp/Cv	EI
4. February 18	Thermal Physics Feb 18: Connections between entropy, temperature, and heat. [Handout: Lab 4--Op Amps] Feb 19: Complex numbers and AC circuits. [Handouts: Corrected versions of Lab 4 and Complex Number and AC Circuits.] Feb 20: AC circuits and op amps. Feb 22: Heat and specific heat. Paramagetism and negative temperatures.	Read Schroeder, Chapter 3 (we'll cover up through 3.4 this week). From Schroeder, Chapter 3: 3.5, 3.7, 3.8, 3.14, 3.15, 3.16, 3.23, 3.25, 3.26.	Lab 4: Operational amplifiers	EI
5. February 25	Thermal physics Feb 25: Third law of thermodynamics. Feb 26: Mechanical equilibrium and pressure. Diffusive equilibrium and chemical potential. Start refrigerators and engines. Feb 27: Op amps Mar 1: Heat engines: efficiency. Carnot cycle: step-by-step analysis, efficiency. Refrigerators.	Finish Schroeder, Chap 3. Also Schroeder 4.1, 4.2, and the first part of 4.2; 6.1,6.2. Problems from Schroeder: 3.34, 3.36, 4.1, 4.3, 4.14, 4.18, 6.5, 6.6	Operational amplifiers	EI
6. March 4	Thermal Physics / Geometrical optics Mar 4: Boltzmann statistics: General idea; derive the Boltzmann factor; probabilities; partition function; (probability-weighted) average values. Mar 5: Op Amps March 6: Exam #1, 7 pm Mar 6: Optics: general intro--connection between wave and geometrical optics mirrors that of stat mech to thermodynamics and quantum mechanics to classical mechanics. Basics of ray optics: index of refraction, law of refraction, law of reflection, total internal reflection, start chromatic dispersion. Mar 8: Chromatic dispersion. Deriving Snell's law using Fermat's principle.	Read Halliday, Resnick & Walker, Chap. 34.7, 34.8, start Chap. 35 Halliday Resnick & Walker, Chap 34: 49,51,56,57; Chap 35: 3,8,11	Operational amplifiers	EI
7. March 11	Geometrical optics Mar 11: Flat mirrors: real and virtual images; ray tracing; front-back reversal. Spherical mirrors: summary of behavior; paraxial rays, focal point. Mar 12: Connecting focal point to radius of curvature. Ray tracing with spherical mirrors. Spherical mirror formula. Magnification formula derived. Sign conventions for spherical mirrors. Mar 13: Derivation of spherical mirror formula. Spherical refracting surfaces: work out all of the cases using ray tracing, summarize with a single formula. Mar 15: Derive spherical refracting surface formula.	Read Halliday, Resnick & Walker, Chap. 35 Halliday Resnick & Walker, Chap 35: 13,15,20,26,29,31,34,35,37	Lab 5: Operational amplifiers	Formal
March 16-24	Spring Break!	nada	woo-hoo!
8. March 25	Geometrical optics / Transverse waves on a string Mar 25: Thin lenses: general discussion; sign conventions; derive thin lens formula and lensmaker's equation from two spherical refracting surfaces. Ray tracing. Mar 26: Thin lenses: magnification formula. Characteristic features of concave and convex lenses. Systems of thin lenses: general treatment; two lenses in the limit that they're close together; two lenses more generally. Start treatment of simple magnifying lens: angular magnification. Mar 27: Finish discussion of simple magnifier. Waves: General discussion of waves on a string. Begin derivation of wave equation using Newton's Second Law. Mar 29: Finish Newton's Second Law derivation of linear 1D wave equation. Progressive wave solution. Transverse velocity << propagation speed. Start D'Alembert solution to wave equation.	Read Towne, Chap. 1 Towne, 1.1, 1.3, 1.8, 1.11, 1.12, 1.13	Lab 6: Mirrors	EI
9. April 1	Transverse waves on a string: General solution, superposition and sinusoidal waves Apr 1: Finish D'Alembert's solution to the wave equation. Interpret results as left- and right-moving waves. Qualitative kinematics of wave. Superposition and sinusoidal waves: importance of sinusoidal waves. Apr 2: Explicit example: nonlinear equations generally lack a linear superposition principle. Sinusoidal waves (both trigonometric and exponential forms): basic features. Aside on small slopes approximation. Relation between simple harmonic motion and waves on a string. Apr 3: Determining waves on a string from initial conditions: two examples. Sinusoidal waves revisited: superposition of two out-of-phase travelling waves. Apr 5: Interference in time: beat phenomena. Interference in space: standing waves. Start Fourier analysis: state Fourier's theorem, in both trigonometric and exponential form. Demo: Beats using two tuning forks.	Reading: There's no single source for this material from the required course texts, so your primary source should be your class notes. However, you might find Chapters 17 and 18 from Halliday, Resnick and Walker helpful. It's on reserve at the Science Library. Problem set distributed in lab on 4/3/02.	Lab 7: Lenses	EI
10. April 8	Fourier analysis Apr 8: More Fourier analysis: relating trig Fourier series coefficients to exponential Fourier series coefficients. Given a periodic function, obtain the coefficients of the trig Fourier series. Recall orthogonality relations for trig functions. Handout: Boas, Chap. 7 (Fourier series) Apr 9: Vector space interpretation of Fourier series. More overlap means large coefficients. Obtaining coefficients for the exponential Fourier series. Start Fourier analysis of square wave. Demo: Fourier Synthesizer applet Handouts: Lab 8; pp. 647-654 from Boas (Fourier transforms) Apr 10: Finish exponential Fourier expansion of square wave. Convert to sine wave expansion. General observations about coefficients. Start discussion of power spectrum. Handouts: Fourier analysis part of lab; solutions to most recent three problem sets; a graded homework. Apr 12: Power spectrum of the square wave: qualitative feature and significance, spectral envelope. Power spectrum of a periodic pulse: calculation, qualitative features, spectral envelope. Bandwidth-pulse duration relation (anticipates uncertainty principle in QM). Fourier transforms: write down the analogs for the Fourier series for nonperiodic functions. Introduce Dirac delta-function in the analog of the orthogonality relation.	Reading: Handouts from Boas. You may find Towne, Chap. 15 helpful also. Problems from Boas handouts: p. 312, #5; p. 321, #18, 20; p. 327, # 23, 24; p. 330, # 4, 10; p. 653, # 9, 12	Lab 8: Fourier Synthesis/Speed of waves	EI
11. April 15	Fourier Analysis / Plane Acoustic Waves Apr 15: Dirac delta function and its use. Example: cosine wave of finite length: Fourier transform to obtain power spectrum. Apr 16: Cosine wave example: obtain spectral width and pulse-bandwidth duration relation. Acoustic plane waves: define variables (including Lagrangian formalism), state assumptions. Derivation of wave equation: start conservation of mass equation. Apr 17: Derivation of wave equation for acoustic waves: finish conservation of mass equation. Newton's second law. Equation of state. Combine these to obtain nonlinear wave equation, then linearize. Obtain expression for speed of sound. Compare prediction for speed of sound to experiment: note discrepancy, attribute it to implicit isothermal assumption. Apr 19: Exam #2, 7 pm Apr 19: Derive correct expression for speed of sound using adiabatic assumption. Re-express in terms of adiabatic bulk modulus. Simplified form of linear equations for acoustic waves in terms of acoustic variables. Impedance: re-express equations in terms of impedance. Write solutions to wave equation (left- and right-movers) in terms of impedances.	Reading: Towne, Chap. 2 Problems: Towne, Chap. 2: 2-8, 2-9, 2-14, 2-16, 2-17, 2-19, 2-20 (due Wednesday, rather than Monday)	Finish speed of waves	Formal
12. April 22	Transmission-Reflection/Energetics of Waves/Interference Apr 22: Analogs between acoustic waves and waves on a string. Sinusoidal acoustic waves and their propagation. Qualitative treatment of transmission-reflection phenomena for waves on a string: reflection from fixed end and free end, transmission and reflection between light and heavy strings. Boundary value problem treatment of transmission-reflection phenomena: "hard" reflections in general and with sinusoidal waves for waves on a string. Acoustic waves reflected from hard surfaces. Apr 23: Boundary value problems: acoustic waves produced by moving boundaries. Transmission and reflection at interfaces with impedance mismatch: general formulation, boundary conditions for fluids (continuity of displacement and of pressure), apply boundary conditions to obtain transmitted and reflected waves. Define velocity transmission and reflection coefficients. Apr 24: Qualitative comments on velocity transmission and reflection coefficients and transmitted and reflected velocity waves. Transmitted and reflected pressure waves, and corresponding coefficients. Examine cases of extreme impedance mismatch. Example: two fluids separated by a massive plate--formulate problem and obtain new boundary conditions. Apr 26: Solve problem in case of incident sinusoidal waves, obtain transmission and reflection coefficients. Note that the plate acts as a low pass acoustic filter.	Reading: Towne, Chap. 3 (you can omit 3.8), and Chap. 4 sections 4.1-4.3, 4.6, 4.8, 4.10-4.12. [If you want more background on this week's lab than is contained in the lab handout, you may wish to read Halliday & Resnick, Chap. 36.] Problems: 3-3, 3-5, 3-6, 3-9, 3-10, 3-17, 4-6, 4-14, 4-15	Lab 9: Measuring light wavelengths with a ruler	Formal
13. April 29	Energetics of Waves / N-source interference and diffraction Apr 29: Instantaneous and average kinetic energy, potential energy, and power for waves on a string. Special case: sinusoidal waves. Apr 30: Energetics of sinusoidal waves. Connection with power spectrum. 2D and 3D waves. Intro to two-source interference for sinusoidal waves. May 1: Average intensity pattern for two-source interference: obtaining convenient forms for the expression in the far-field limit. May 3: Shortcut to the far-field limit approximation. Start N-source interference.	Reading: HRW Chap. 36 and 37 give the fundamentals. Towne, Chap. 11 (sec. 1-8) and 12 give more details. Problems: HRW Chap 36, # 29, 43, 60; Chap 37, # 12, 18, 24, 25, 30, 38, 64; Towne Chap 11, #6	Lab 10: Two-source interference	EI
14. May 6	N-source interference and diffraction May 6:Interference notebook Finish N-source interference. Phasor approach to N-source interference. May 7:Diffraction patterns Diffraction: generalities, formulate as N-source problem. May 8: Diffraction: Derive expression for totat wavefunction in Fraunhofer approximation. May 10: Diffraction: finish the single-slit problem, understand the qualitative behavior from exact solution.	No required problem set.	Finish interference; Course evaluation	EI
May 13-17	Final exam period	Final: TBA

Website

Useful Links

Interesting talks in the Five-College area:

Area Seminars and colloquia

Interesting and useful papers:

Interesting and useful websites:

Six Ideas website

Statmech program referred to in the Six Ideas text (if that doesn't work try this .zip version).

Stirling Engine Society website

Swallowing LN2 in the Darwin Awards (thanks to Mark Wheeler)

LN2 ice cream (thanks to Mark Wheeler)

LN2 and Guiness (see italics at the bottom of that page. Thanks to Mark Wheeler)