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Physics Honors/AP 1 and 2

Chapter 18: 1-6

Course Materials are always under revision! Weblecture content may change anytime prior to two weeks before scheduled chat session for content.

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Homework

Physics 18: 1-6 Electric Current and Resistivity

Homework

Reading Preparation

Text Reading: Giancoli, Physics - Principles with Applications, Chapter 18: Sections 1 to 6

Study Points

Key Equations

  • Current definition: I   =   Δ Q Δ t
  • Resistance: V   =   IR
  • Resistivity: R   =   ρ l A
  • Temperature dependence of Resistivity: ρ T = ρ 0 [ 1   +   α ( T   T 0   ) ]  
  • Electric power P   =   IV   =   I   ( IR )   =   I 2 R P   = IV   =   ( V R ) V   =   V 2 R   P   =   IV   =   ( Q t ) V

Web Lecture

Read the following weblecture before chat: Direct Current

Study Activity

Use the simulation below to explore how changibng resistivity, length, and cross-secttion area changes the total resistance in a conducting wire.

  • What happens to Resistance R as you vary resistivity ρ? When is Resistance R the greatest? The least?
  • What happens to Resistance R as you vary length L? When is Resistance R the greatest? The least?
  • What happens to Resistance R as you vary area A? When is Resistance R the greatest? The least?
  • How can you maximize resistance? What is the largest value of R you can achieve?

Physics simulation Java Applets are the product of the PHET Interactive Simulations project at the University of Colorado, Boulder.

Chat Preparation Activities

Chapter Quiz

Lab Work

If you want lab credit for this course, you must complete at least 12 labs (honors course) or 18 labs (AP students). One or more lab exercises are posted for each chapter as part of the homework assignment. We will be reviewing lab work at regular intervals, so do not get behind!