1. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Current Conservation of current Batteries Resistance and resistivity Simple circuits Chapter 22 Current and Resistance Topics: Sample question: How can the measurement of an electric current passed through a person’s body allow a determination of the percentage body fat? Slide 22-1

2. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Large Hadron Collider is now creating proton collisions at 7 TeV (That’s 7 trillion electron Volts) Most energetic collisions seen in a particle accelerator Less energy than two flies colliding Less energy than most energetic cosmic rays colliding with atoms in upper atmosphere Slide 22-11

3. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Drawing Circuit Diagrams Slide 23-8

4. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Simple Circuits The current is determined by the potential difference and the resistance of the wire: Slide 22-13 I = ∆ V chem R _____

5. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Resistivity The resistance of a wire depends on its dimensions and the resistivity of its material: Slide 22-14

6. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Power in Circuits Slide 22-19

7. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Kirchhoff’s Laws Slide 23-11

8. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Using Kirchhoff’s Laws Slide 23-12

9. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Series Resistors Slide 23-17

10. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Parallel Resistors Slide 23-18

11. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. Analyzing Complex Circuits Slide 23-20

12. Copyright © 2007, Pearson Education, Inc., Publishing as Pearson Addison-Wesley. For the circuit below, find the equivalent resistance Find the Equivalent Resistance for this system for the following case R 1 = R 2 = R 3 = R 4 = R 5 = 2 ohms and  V bat = 1 V Note: First redraw the circuit tracing the current from the battery Slide 22-11 Equivalent Resistance Example