Welcome to Physics 1161! Electricity & Magnetism (E&M) Optics Quantum Physics Atomic Physics Nuclear Physics Relativity http://online.physics.uiuc.edu/cc/eastern/phy1161/spring/ Physics 1161: Lecture 1, Slide 1

Instructor Cherie Bibo Lehman cblehman@eiu.edu Please include course number and section in subject 1112 Physical Science -- 217.581.5904 Office Hours Monday: 10:00 AM – 11:00 AM Tuesday: 2:00 PM – 3:00 PM (rm2167) Wednesday: 2:00 PM – 4:00 PM (rm2153) Friday: 10:00 AM – 11:00 AM http://ux1.eiu.edu/~cblehman/ Physics 1161: Lecture 1, Slide 2

Course Philosophy Read about it (textbook and prelecture) Think about it (preflights) Sort it out(lectures) Play with it (labs) Challenge yourself (homework) Close the loop (discussion/quiz) Lectures M,W HW due 8 AM Tuesday the following week Disc Tues-Fri, the week following the lecture Quiz: due two days after Disc The order is important! Physics 102: Lecture 1, Slide 3

Grade Components Preflights 5% Class Participation* 5% Homework & Quizzes 25% Hour Exams (highest 3 of 4) 35% Final Exam 30% 100% *Based on clicker responses Physics 1161: Lecture 1, Slide 4

Grading Scale 90-100 A 80-89 B 70-79 C 60-69 D <60 F Physics 1161: Lecture 1, Slide 5

Pre-Lectures 24 hours prior to each class, I will post on the schedule a link to a pre-lecture power point. You should go through the pre-lecture and read the relevant sections in the text before you move on to the preflight. Physics 1161: Lecture 1, Slide 6

Preflights Complete the preflights - 5% of your grade 2 points (full credit) for honest attempt at preflight. Must do the entire preflight to earn any credit, including responding to questions about what you find most interesting or most difficult. Click on link from Schedule Page. You will be transferred to UIUC’s Tycho server and will be asked to log on. Your userid is your EIU userid. Your password is also your userid. I recommend that you change your password right away. Physics 1161: Lecture 1, Slide 7

Homework I have set up 14 homework assignments on UIUC’s Tycho server. Once again, you will have to log on. You can access hints as you work through the problems, and you can work a problem as many times as needed in order to obtain full credit. After the due date, you will have about 5 days to submit the homework for 90% credit.

Mastering Physics You have been issued a code number. Use this code number to log on to www.masteringphysics.com. Online problems which we will use from time to time Online textbook ActivPhysics – interactive problems

P1161 Lectures Not everything you need! Taking Notes Untangling and clarification of concepts & processes Comprehensive Textbook Calculations Homework + Discussion Hands-On Lab Taking Notes Lecture note handouts will be available online prior to class Key pieces for you to fill in Physics 1161: Lecture 1, Slide 10

Origin of Charge Charge is an intrinsic property of matter Two types: Positive Charge: Protons Negative Charge: electrons Opposites Attract! (likes repel) Atoms are neutral Negatively charged electrons “orbit” r~10-10 m Positively charged central nucleus r~10-15 m Copper and wood both made of atoms, both have positive and negative charges, but are electrically very different. Why? Physics 1161: Lecture 1, Slide 11

Conductors and Insulators Q: How do electrons behave in a perfect conductor? Q: How do electrons behave in a perfect insulator? Copper and wood both made of atoms, both have positive and negative charges, but are electrically very different. Why? Most things are in between perfect conductor / insulator Physics 1161: Lecture 1, Slide 12

Conductors & Insulators

Charge Coulomb (C) Coulomb is a huge unit of charge Standard unit of charge Coulomb (C) Coulomb is a huge unit of charge Charge on one electron or proton is: A small spark between your finger and a door knob on the order of Helium atom

Charging an Electroscope Conduction Induction Do the demo first, then show the visualization. Comment on how electroscope works. It’s like VandeGraaff and hair standing on end.

A negatively charged rod is used to charge an electroscope by induction. What is the resulting net charge on the electroscope? Positive Zero Negative

If the conducting electroscope were replaced by an insulating ball and then charged by induction as above, what would be the net charge on the ball. Positive Zero Negative

Law of Electrical Force Charles-Augustin Coulomb (1736 - 1806) " The repulsive force between two small spheres charged with the same sort of electricity is in the inverse ratio of the squares of the distances between the centers of the spheres" q2 q1 r 7

Coulomb's Law q1 q2 8

Summary Charges come in two varieties Coulomb Force Law of Superposition

® ® Gravitational vs. Electrical Force For an electron: F = 1 4 pe q r m1 q2 m2 F elec = 1 4 pe q 2 r grav = G m ® * smallest charge seen in nature! For an electron: * |q| = 1.6 ´ 10-19 C m = 9.1 ´ 10-31 kg ® .

In the picture below, what is the direction of the force on the proton due to the electron? Left Right Zero + - r = 1x10-10 m Qp=1.6x10-19 C Qe = -1.6x10-19 C

What is the magnitude of the force on the proton due to the electron? + - r = 1x10-10 m qp=1.6x10-19 C qe = -1.6x10-19 C F F= _______ N

A positive and a negative charge with equal magnitude are connected by a rigid rod, and placed near a large negative charge. What is the direction of the net force on the two connected charges? Left Zero Right + -

To Do See you next time! Purchase and register your clicker. Use your code to log on to and activate your MasteringPhysics account. Through this account you can access Online version of textbook ActivPhysics Read Sections 19-1 -- 19-5 Do preflight 1 before 11:00 PM 12/12/10. Do preflight 2 before 6:00 AM 12/13/10 See you next time!

Lab Section 02 at 9 AM on Tue will meet in Gregg computer lab this week. Lab sections 01 and 03 will meet in the normally scheduled room.