Electromagnetism I TECHNICAL DETAILS

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1 Electromagnetism I TECHNICAL DETAILS Instructors: D. Mark Riffe Office: SER 222B Phone: mark.riffe@usu.edu Office Hours: open door policy Prerequisites: PHYS 2710, MATH 2210, 2250 Required Text: Introduction to Electrodynamics (Fourth Edition) by David J. Griffiths. Credits: 3 credit hours Lecture: Tu Th, Technology 122, 10:30 11:45 am Course Website: on canvas.usu.edu OVERVIEW Subject matter. The theory of classical electrodynamics is a general framework for describing and explaining the interactions of charged particles and objects (composed of charged particles) via electric and magnetic fields. Along with classical particle mechanics, this theory forms the foundation for understanding much of contemporary physics, especially quantum particle mechanics and quantum electrodynamics. Classical electrodynamics lies at the heart of a huge variety of technology and natural phenomena; the topics in this course are the foundation for applications in such diverse areas as electric power generation, analog and digital electronics, optics, and radiowave communication. Specifically, in this course we shall cover two basic topics electrostatics and magnetostatics. Electrostatics is the study of static electric fields produced by static charge distributions. This topic also includes the interaction of matter with such electric fields. Analogously, magnetostatics is the study of static magnetic fields produced by steady-state current distributions. Magnetostatics also includes the interaction of matter with such magnetic fields. As we shall see, these two topics parallel each other quite closely. Importantly, the ideas introduced in describing static fields lay the foundation for the study of dynamic electromagnetic fields, the general subject of the follow-on course, PHYS While you have already been exposed to electromagnetism in your introductory physics sequence, we shall now discuss this material at much higher 1

2 conceptual and mathematical levels than you have previously encountered. At times, the word abstract may be an appropriate term to use. In many ways you are at the beginning of your foray into modern theoretical physics. It will likely not be easy, but I hope it will be fun! COURSE GOALS (Students should be able to...) Connection between math and physics. Students should be able to translate a physical description of an electrodynamics problem into the mathematical equations necessary to solve it. Students should be able to explain the physical meaning of the mathematical formulation of an electrodynamics physics problem and/or its solution. Students should be able to achieve physical insight through the mathematics associated with a problem. Problem visualization. Students should be able to sketch an appropriate illustration of a physical problem, including any relevant coordinates. Graphical representation Students should be able to construct a graph appropriate to a particular problem or its solution, including the use of normalized variables on the axes of the graph. Knowledge organization. Students should be able to articulate the big ideas from each chapter, section, and/or lecture, thus indicating that they have organized their content knowledge. Students should be able to filter this knowledge to access the information they need to for a particular physical problem, and make connections between different concepts. Problem-solving techniques. Students should be able to choose and apply a problem-solving technique appropriate to a particular problem. Students should be able to justify their approach for solving a particular problem. Problem-solving strategy Students should be able to (i) draw upon an organized set of content knowledge and (ii) apply problem-solving techniques relevant to that content in order to organize and carry out long analyses of physical problems. Students should be able to connect the pieces of a problem to reach the final solution. Students should recognize that mistakes are valuable in learning the material, be able to recover from such mistakes, and persist in working to the solution even though they may not necessarily see the path to the solution when they begin the problem. Students should be able to articulate what needs to be solved in a particular problem and know when they have solved it. Approximations. Students should be able to recognize when approximations are useful and use them effectively. For example, students should 2

3 be able to recognize when a truncated series expansion is an appropriate approximation to an exact solution. Students should become facile with Taylor series expansion of functions, including (i) being able to identify the small parameter of the expansion, and (ii) knowing how many terms in the expansion to keep when using the series to approximate an exact expression. Expecting and checking solution. When appropriate for a given problem, students should be able to articulate their expectations for the solution, such as direction of a field, dependence on coordinate variables, and behavior at small or large distances and/or times. For all problems, students should be able to assess the reasonableness of a solution they have reached, by methods such as checking the symmetry of the solution, looking at limiting or special cases, relating the result to cases with analogous solutions, checking units, using dimensional analysis, and/or checking the scale/order of magnitude of the answer. Communication. Students should be able to justify and explain their thinking and/or approach to a problem or physical situation, in either written or oral form. Students should be able to write up problem solutions that are well-organized, clear, and easy to read. Intellectual maturity. Students should accept responsibility for their own learning. They should be aware of what they do and do not understand about physical phenomena and classes of problem. This is evidenced by asking sophisticated and specific questions, being able to articulate where in a problem they experienced difficulty, and taking action to move beyond that difficulty. SCHEDULE The schedule for the lectures (and not coincidentally, the reading assignments) can be found in the table on the following page. In essence, we shall work our way through Chapters 2-6 of the text. As necessary, mathematical material from Chapter 1 will be included. READING QUIZZES In order to encourage you to keep up with the material (and to make lectures more profitable), there will be online reading quizzes, administered through Canvas. Generally, there will be a quiz before each class period. Each quiz will contain on the order of 5 questions, most of which should be readily answerable after reading the associated material in the text. The primary deadline for each quiz is the night before the associated lecture, 3

4 Table 1: Reading Assignments and Lecture Schedule Week of Tuesday Thursday Aug 29 Sept 5 Sep 12 Sep 19 Sep 26 Oct 3 Oct 10 Oct 17 Oct 24 Oct 31 Electric field E / electric force / Charge distributions (Ch. 2: 59-65) Scalar potential V (Ch. 2: 78-84) Work and energy (Ch. 2: 91-97) Buffer / Review Laplace s equation (Ch. 3: ) Separation of variables: Cartesian coordinates (Ch. 3: ) Multipole expansion of V and E / electric dipole p (Ch. 3: ) Polarized object E field (Ch. 4: ) Displacement field D (Ch. 4: ) Buffer / Review Nov 7 Magnetic field B / Magnetic force (Ch. 5: ) Nov 14 Nov 21 Biot-Savart law (Ch. 5: ) Vector potential A (Ch. 5: ) Nov 28 Boundary conditions / Magnetic dipole m (Ch. 5: ) Dec 5 Dec 12 Auxiliary field H (Ch. 6: ) Final Exam (Comprehensive / Chs. 5-6) 11:30 am 1:20 pm Divergence and curl of E / Gauss law (Ch. 2: 66-78) Scalar potential / Boundary conditions (Ch. 2: 84-91) Conductors (Ch. 2: ) Exam I (Ch. 2) Method of images (Ch. 3: ) Separation of variables: Spherical-polar coordinates (Ch. 3: ) Electric fields in matter / Polarization field P (Ch. 4: ) Fall Break (Friday schedule) Linear response (Ch. 4: ) Exam II (Ch. 3-4) Currents (Ch. 5: ) Divergence and curl of B / Ampere s law (Ch. 5: ) Thanksgiving Break Magnetic fields in matter / Magnetization field M (Ch. 6: ) Buffer / Review 4

5 at 1 AM. For full credit, each quiz must be completed before the primary deadline. A secondary deadline occurs 2 days after the primary deadline. The scores on quizzes completed between these two deadlines are worth 50% of their full value. No quizzes may be completed after the secondary deadline. N.B., the first quiz is due the night before the first lecture. HOMEWORK Assignments. Each lecture will have an associated homework assignment. Best practice is to work through each weeks assignments before the next weeks lectures, as this will help you (i) internalized the material and (ii) be ready for upcoming class periods. In order to prepare for the exams, it is strongly suggested you keep your solutions for all the problems together in one place, such as a three-ring binder or spiral notebook. Homework problems will not be collected (and therefore not graded), but the exams will be strongly based on the assigned homework. If you have worked out (and understood) the assigned problems, you should do well on the exams. Supplemental instruction / Recitations. A teaching assistant (TA) assigned to the course will lead regularly scheduled recitation sections. The TA will answer any question you have regarding course material, especially assigned homework problems. Importance of Homework. The main point of doing homework is to have you actively engage with the material. Such engagement leads to the development of neural pathways associated with learning. To enhance the learning process it will be helpful to ask yourself, after having worked out each problem, What was the point of this problem; what should I have learned here? Most importantly, you should treat the homework as an opportunity to learn rather than some drudgery to simply slog through. You will be best served if you intentionally set specific, regular times aside to work on the homework. The homework will likely take you several hours to complete, and so putting it off until a day or two before the exam will only produce stress, fatigue, and minimal learning from the experience; it will then simply be an unpleasant descent into paralyzing quicksand. Engaging with the homework can positively affect your exam scores. This is clearly illustrated in In Fig. 1, which plots exam scores vs the fraction of homework problems attempted (related to that exam) for a recent PHYS 3550 class. As the data show, If you want a high score on the homework, you must engage the homework. Conversely, if you want a low score, don t bother looking at the homework. The data also show that doing the homework is 5

6 Exam 1 Score HW Problems Attempted (fraction) 1.0 Figure 1: Scores on Exam 1 in PHYS 3550 (SP 2015) vs the fraction of homework problems attempted. no guarantee of doing well on the exam. This is likely related to a couple of factors. First (as discussed above), one s approach to the homework has an impact on the learning process. Second, for most people effective preparation for an exam includes other modes of study, such as textbook reading and reviewing, for example. COLLABORATION IS ENCOURAGED I strongly encourage collaboration, which is an essential skill in science (and highly valued by employers!) Social interaction is critical to the success of all scientists most good ideas grow out of discussions with colleagues; essentially all scientists work as part of a research team. Find a partner or two with whom you can discuss the homework. However, it is also important that you own the material. Limit yourself to verbal help; don t ever take written information from others, and don t take written notes when you talk to others. This practice will ensure that you think things through independently after you get help. If you complete the homework but do poorly on exams, then you are probably getting too much help. The point of the homework is not to just find the answer, but more importantly to discover how to obtain the answer. There will be time for peer discussion during classes where you will try to help your fellow students get over confusions by listening to them, asking questions, critiquing answers, and teaching each other. You will learn a lot this way! While collaboration is the rule in technical work, the evaluation of each 6

7 individual also plays an important role. Exams will be done without help from others. The reading quizzes are to be done by yourself. EXAMS There will be two midterm exams and a comprehensive final exam. The midterm exams shall take place during the regularly scheduled class time; see the schedule above. The comprehensive final exam is on 11:30 AM - 1:20 PM, Tuesday, December 13, The final must be taken at this time. HOW TO SUCCEED IN THIS COURSE You can perform very well in this class if you adhere to the following set of recommendations. Read the relevant sections in the text before each class. By reading before class, the time spent during the class will be much more beneficial. The reading quizzes are (obviously) designed to encourage this activity Take detailed notes on your reading of the text and write down questions so you can ask them in class. Come to class and stay involved. Ask questions! Keep up with the homework. Schedule time to work and internalize the material. No one is smart enough to do the homework in the last hours before each exam, and no one is smart enough to learn the material without working the homework problems. Work together when necessary. Do your own thinking, but talking to others is a great way to get unstuck. Don t get behind. It s very hard to catch up. GRADING Scores on reading quizzes and exams contribute to your final grade. The percentage that each contributes is as follows. Reading quizzes 10% First midterm exam 25% Second midterm exam 30% Final exam 35% 7

8 The nominal grading scale is listed below. Some adjustments to this scale may be made if deemed necessary by the instructor. A 93%, A 90%, B+ 87%, B 83%, B 80%, C+ 77%, C 73%, C 70%, D+ 67%, D 60% DISABILITY Students with ADA-Documented physical, sensory, emotional or medical impairments may be eligible for reasonable accommodations. Veterans may also be eligible for services. All accommodations are coordinated through the Disability Resource Center (DRC) in Room 101 of the University Inn. (435) voice, (435) TTY, (435) VP, or toll free at Please contact the DRC as early in the semester as possible. Alternate format materials (Braille, large print or digital) are available with advance notice. HONOR CODE The honor code will be strictly enforced in this course. Any suspected violations of the honor code will be promptly reported to the honor system. For more information please visit: Integrity.pdf POSSIBLE ERRORS The instructor reserves the right to correct any possible errors in this syllabus. 8

Penn State University - University Park MATH 140 Instructor Syllabus, Calculus with Analytic Geometry I Fall 2010

Penn State University - University Park MATH 140 Instructor Syllabus, Calculus with Analytic Geometry I Fall 2010 There are two ways to live: you can live as if nothing is a miracle; you can live as if