I've corrected the mid-term exam dates in the text below. The dates that were in the table were correct. Please let me know if you have any conflicts.
The bookstore doesn't have the textbooks yet, and no one was able to tell me when they'd arrive when I called today. I'll let you know more when I know. In the meantime, I've photocopied the first chapter of Schoeder and left it outside my office. It's in two parts, so make sure to pick up both parts.
I'll tentatively schedule my office hours for: Monday 11-12 am, Tuesday 10-11:30 am, and Wednesday 1-2 pm, or by appointment. You're also welcome to drop in to my office. If I'm in and I'll talk to you if I'm free, but that's not so often during the day.
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.
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.
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.
I'd like to schedule the mid-term exams outside normal class hours Wed. March 6, 7 pm, and Wed. April 17, 7 pm.
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.
Required (should be available at the Jeffrey Amherst bookstore):
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 |