PHYS 100C v2012

Revision as of 20:07, 13 May 2012

Welcome to Physics 100C webpage for Spring'2012 Quarter.

RECENT UPDATES:

• May 12: Homework #5: 10.13, 10.17, 10.20. Hints for 10.13: v is perpendicular to r. Hints for 10.17 - consider value of |r|, using the fact that |r|=sqrt(r*r), and differentiate it with respect to time. Hints for 10.20: r is perpendicular to v and parallel to a.
• May 8: Today we got through two sets of notes for Lecture 11 (PDF) and Lecture 12 (PDF), skipping some repetitive mathematical details and focusing on the physics instead. Reminder that the midterm is this Thursday, May 10th in place of class, it is open book (notes and textbook allowed, electronic version of notes/book on laptops/tablets is Ok too).The midterm will be on Chapter 9 material.
• May 6: there will be no homework due this week. Next homework will be due Thur, May 17th.
• May 4: midterm will cover chapters 9 and 10 or roughly the first 4 weeks (lectures 1 thru 8). Problem similar to homeworks. Mock midterm from 2009 is here: Midterm (PDF), Midterm solutions (PDF).
• May 1-3: NOTE - there will be NO Discussion session on Friday, May 4th. Next Thursday, May10th is Midterm exam. Lecture 9 (PDF) Summary: Lienard-Wiechert potentials for moving charge, expanded. Velocity and acceleration contributions to E derived. HW #3 Solutions (PDF) posted. Lecture 10 (PDF) Summary: we derived the radiated E, B fields for oscillating dipole, using retarded potential formalism (11.1.1, 11.1.2 in the textbook). Result is spherical EM wave (transverse), intensity ~ fourth power of frequency (Rayleigh scattering and the reason for why the sky is blue), decays as inverse square of distance, has sin²(theta) angular anisotropy with respect to dipole orientation.
• April 27: Lecture 8 (PDF) Summary: derived Jefimenko Eqs (fields from retarded potentials) 10.2.2. Derived general expression for Lienard-Wiechert potentials for moving charges. (10.3.1).
• For those interested in deep discussions (obviously not required for this course!) on nature and direction of arrow of time see here, here, here, or here, or google "Boltzmann's Brain", "Arrow of time" or "Gibbs paradox".
• April 25: Lecture 7 (PDF) Summary: we introduced gauge transformations (10.1.2), Coulomb and Lorentz gauges, and Maxwell equations in these gauges (10.1.3). Introduced "retarded" potentials in Lorentz gauge and demonstrated that they are a solution to Maxwell equations for potential V(r,t) (10.2.1).
• April 23: Lecture 6 (PDF) covered waveguides and beginning of gauge formalism.
• April 19: Group vs. phase velocity animation.
• April 17: Lecture 5 (PDF) summary: we considered a simple mass-on-a-spring model for electron driven by electromagnetic wave to calculate dependence of index of refraction and attenuation as a function of frequency, leading to dispersion (rainbows etc.) We started deriving propagation of EM waves in a hollow metallic waveguide.

• April 15: The homework grades can be seen in this google doc. Find your grades by the last 3 digits (sometimes 2 - if starts with 0, and sometimes 4 digits if degeneracy arises) of your PID.

• April 14: Lecture 4 (PDF) Summary (with a tilda): we considered E&M waves propagating in conducting materials. Wavevector k becomes complex, with imaginary part of k representing exponential attenuation of the wave (skin depth introduced). E&M are still transverse but no longer in phase. Re-deriving the boundary conditions (Lecture 2/3 with complex k) get 100% reflection - explains why metal objects/mirrors are shiny.

• April 10: Lecture 3 (PDF) summary: we considered boundary conditions for a plane EM wave incident on an interface at arbitrary incident angle. We have derived three laws of reflection/refraction and derived Fresnel Law for p-wave.

(p stands for parallel, s stands for senkrecht, German word for "perpendicular" - to the plane of incidence). We have considered Brewster angle physics which included polarized sunglasses and Brewster Angle Microscopy.

• April 5: Lecture 2 (PDF) summary: we considered energy and pressure carried by radiation / EM wave. We have looked at propagation of waves in media; We derived transmitted and reflected wave equations for a plane EM wave normal-incident at the boundary between two media (using boundary conditions from Eq. 7.64).

April 3: Lecture 1 (PDF) summary: we covered waves in 1D (9.1.1-9.1.2), discussed transverse/longitudinal waves (9.1.4), derived EM waves in vacuum from Maxwell Eqs. (9.2.1, 9.2.2).

• Note that in class I will be using my own lecture notes from 2009, which are made available here. This will ruin the element of surprise but will allow you to follow along and correct any mistakes you may find.

• Historic Perspective (not required, but could be of interest for those of you who like the history of science): the fact that light is E&M wave was *almost* derived by Wilhelm Eduard Weber and Rudolf Kohlrausch in 1856, and speed of light was measured by Fizeau in 1848 and Foucault in 1850. Maxwell made the connection in 1861.

Einstein wrote about this prediction:Of Maxwell's work:

"Imagine [Maxwell's] feelings when the differential equations he had formulated proved to him that electromagnetic fields spread in the form of polarised waves, and at the speed of light! To few men in the world has such an experience been vouchsafed... it took physicists some decades to grasp the full significance of Maxwell's discovery, so bold was the leap that his genius forced upon the conceptions of his fellow-workers."

Maxwell's conjecture was proven by Hertz in 1887, who was only 4 years old in 1861, when Maxwell first postulated that light is Electromagnetic Wave.

COURSE SUMMARY:

PHYS 100C, Electromagnetism, Spring 2012, UC San Diego

Professor: Oleg Shpyrko, oleg@physics.ucsd.edu

Office: Mayer Hall 3210, ext. 4-3066 (Where is it?)

Office Hours: Mondays 4-5PM as well as Discussion Session on Friday.

TA (Grader): Leandra Boucheron, lboucheron@gmail.com

Text: Introduction to Electrodynamics, 3rd Edition, by David J. Griffiths. (also check abebooks for used copies)

Lectures: Tue, Thu, 12:30PM-1:50PM, YORK 4080A

Discussion Session: Fridays 2-2:50PM, SOLIS 111. Homework: Assigned weekly, due Thursdays, at the START of lecture. Will also be accepted at the following Tue lecture, but with a 20% penalty.

Midterm: Thursday, May 10th, 12:30PM-1:50PM YORK 4080A (in class). Open book exam. Bring your textbook only, and a bluebook.

Final: June 11, 11:30AM, Room TBD. Open book exam. Bring your textbook, notes, and a bluebook.

Grading: Homework=20%, Midterm =30%, Final=50%.

Academic Dishonesty: Please read the section entitled "UCSD Policy on Integrity of Scholarship" located in the2008-2009 General Catalog, www.ucsd.edu/catalog. The rules on academic dishonesty will be strictly enforced!

Course Webpage: x-ray.ucsd.edu/PHYS_100C (RSS/Atom feeds available) ---

COURSE SCHEDULE: