1. Welcome to Physics 1161! Electricity & Magnetism (E&M) Optics
Quantum Physics
Atomic Physics
Nuclear Physics
Relativity
Physics 1161: Lecture 1, Slide 1

2. Instructor Cherie Bibo Lehman cblehman@eiu.edu
Please include course number and section in subject
1112 Physical Science
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
Physics 1161: Lecture 1, Slide 2

3. 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

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

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

6. 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

7. 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

8. 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.

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

10. 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

11. 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

12. 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

13. Conductors & Insulators

14. 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

15. 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.

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

17. 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

18. 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

19. Coulomb's Law q1 q2 8

20. Summary Charges come in two varieties Coulomb Force
Law of Superposition

21. ® ® Gravitational vs. Electrical Force For an electron: F = 1 4 pe q rm1 q2 m2 F
elec = 1 4 pe q 2 r
grav
= G m
* smallest charge seen in nature!
For an electron:
* |q| = 1.6 ´ C
m = 9.1 ´ kg .

22. 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

23. 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

24. 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 + -

25. 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
Do preflight 1 before 11:00 PM 12/12/10.
Do preflight 2 before 6:00 AM 12/13/10
See you next time!

26. 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.