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Electricity and Magnetism. Physics 208. Dr. Tatiana Erukhimova. Dr. Tatiana Erukhimova. [year]. Atmospheric Thermodynamics Elementary Physics and Chemistry Gerald R. North Tatiana L. Erukhimova Texas A & M University. SLATE award: 2008, 2009, 2011
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Electricity and Magnetism Physics 208 Dr. Tatiana Erukhimova
Dr. Tatiana Erukhimova [year]
Atmospheric Thermodynamics Elementary Physics and Chemistry Gerald R. North Tatiana L. Erukhimova Texas A & M University SLATE award: 2008, 2009, 2011 Recipient of 2009 Distinguished Achievement College-Level Award in Teaching
Overview of Today’s Class • Syllabus and Course requirements • Tricks to survive • Mechanics Review and Coulomb’s Law
Syllabus Instructor Dr. Tatiana Erukhimova Homepagehttp://faculty.physics.tamu.edu/etanya/P208/ Office: Mitchell Physics bldg (MPHY), Room 308
Phone: 845-5644 E-mail: etanya@tamu.edu Class times: MWF: 9:10 am to 10:00 am Sections 522-527 Location: MPHY 205 Office hours: Monday and Wednesday 1pm – 3pm or by appointment
Textbook: “Don’t Panic: Volume II”, by William H. Bassichis, 5th Edition Dedicated students like it! No lab manual is required
Grade Policy Exams 45% Lab 5% Quizzes 10% Final 40%
Grade Policy (cont) You must pass both the lecture (3 midterm exams, final exam, homework) and laboratory parts of the course in order to pass the course
Grade Policy (cont) • If your grade on the Final Exam is higher than your lowest grade on one of the three exams during the semester, the grade on the Final will replace that one lowest exam grade in computing the course grade (it will only replace one grade in case of two exams having the same lowest grade). • The Final Exam grade cannot be used to replace an exam that has been missed without an University excused absence. The missed exam will count as a zero when computing your final grade.
All Exams are • Closed book • No numbers! In general the problems will be formula solutions with variables • Problems will be similar to those on homework and recitation
Homework You’ll have weekly homework assignments Every week you’ll have hw quiz with one problem from your assignment. All quizzes will be given with CPS clickers
Check my webpage for hw assignments Example for Week 1 (Week Jan 16): Week Jan 16 (due Jan 23): All Chapter 1 problems and exercises “Due” means that I’ll give you a hw quiz on that day
Homework (Cont) Reading quizzes Please buy clickers (CPSrf responder) You will need to buy the clickers at the MSC Bookstore and register them for this class at http://elearning.tamu.edu (NOT www.einstruction.com) You will earn points for reading quizzes based on your participation in class as documented via use of your CPSrf responder. You will not be able to earn points if you fail to bring your personally registered CPSrf responder with you to class each day.
Exam schedule All mid-term exams will be from 7:00 to 9:30 pm February 14 Exam I March 20 Exam II April 17 Exam III Final May 4
My Advice to You • Be proactive!! Get into it and have fun • Always read the book before you come to class • Be serious aboutan old rule of thumb:you have to study 2-3 hours a week outside the class per each credit hour • Don’t miss classes (lectures, recitations, labs) • Solve all problems and exercises after each Chapter in the book • Don’t fall into the “I understand the concepts but I can’t do the problems” trap. It means you haven’t done enough of the problems in the chapters. • Every year we have lots of students who really think they understand but fail during the exams. Don’t let this happen to you!
Help sessions are every Monday 15 min before the class I also make help sessions before each midterm exam and the final. (and Monday?) However, these sessions cannot substitute for regular class attendance. They are to give you a good guidance on how to prepare for the test and to succeed in problem solving. Please check my webpage for help sessions schedule
A little bit of Mechanics A couple of very important concepts: Work Energy Theorem ____
Sir Isaac Newton: The Universal Law of Gravitation
m m = - 1 2 U ( r ) G r We can find Gravitational Potential Energy
Consider a force like gravitation which varies as but 1) billion-billion-billion-billion times stronger; 2) there are two kinds of “matter”: positive and negative; Like kinds repel and unlike kinds attract (unlike gravity where there is only attraction) + + _ + _ _
Electrical force All matter is a mixture of positive protons and negative electrons which are attracting and repelling with this great force. How perfect is the balance? -when you stand near someone else you don’t feel any force at all; -if you were standing at arm’s length from someone and each of you had one percent more electrons than protons, the repelling force would be enough to lift a “weight” equal to that of the entire earth! The force that holds atom together, and the chemical forces that holds molecules together, are electrical forces!
Atoms are made with positive protons in the nucleus and with electrons outside This picture is obsolete!
-There are also nuclear forces – fall off much more rapidly than If this electrical force is so terrific, why don’t the protons and electrons just get on top of each other? Laws of quantum mechanics rule it out… What holds the nucleus together? A Helium Atom
An important consequence….. Consider uranium with 92 (!) protons. The balance between the nuclear forces and electrical repulsion is so delicate that the nucleus is almost ready to fly apart. If we “tapped” it slightly……
What holds a negatively charged electron together ? (since it has no nuclear force) 1909: Robert Millikan famous oil drop experiment The smallest charge we ever observed is the “elementary charge”: By convention, the electron has negative sign, the proton positive.
Charge is the permittivity of free space Charge Coulomb’sLaw Conservation of electric charge Charge is conserved: in any isolated system, the total charge cannot change. If it does change, then the system is not isolated: charge either went somewhere or came in from somewhere
Have a great day! Hw: All Chapter 1 problems and exercises Reading: Chapter 1