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Physics Honors/AP 1 and 2

Chapter 20: 5-12 Assignment

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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Physics 20: 5-12 Electromagnets


Reading Preparation

Text Reading: Giancoli, Physics - Principles with Applications, Chapter 20: 5 to 12

Study Points

Key Equations

  • Magnetic field strength near a current-carrying straight wire: B   =   μ 0 2 π   l r   =   μ 0 I 2 π r    
  • Force between two current carrying wires: F   =    μ 0 I 1 I 2 2 π d
  • Ampère's law: B | |    Δ l   =   μ 0 I
Magnetic field strength near a straight wireB = μ0I/2πrμ0 is the permeability constant, which determines how magnetic force is propagated through a medium. The "0" indicates this is the propagation constant for a vacuum or "free space", which has the value 4 π * 10-7 T•m/A2. Steel has a permeability about 100 times that of a vacuum, making it a good "magnetic conductor".
Force on paralle conductorsF = μ0 I1I2 l / 2 π dThis gives the force on a length l of wire #2 due to current I1 in wire 1 and I2 in wire two, when the wires are a distance d apart.
Magnetic field of solenoidB = μ0 IN/lThis gives the strength of the magnetic field generated by current I running through N loops of a wire within a given distance l
Ampère's LawΣ B|| Δ l = μ0 IencThe general rule for any closed path of segments Δl enclosing a medium carrying carrying current Ienc. This rule allows us to consider situations other than the field near a straight wire.

Web Lecture

Read the following weblecture before chat: Ampere's Law and Electromagnets

Study Activity

Use the physics simulation for a Charged Particle in a Magnetic Field — 3D.

  • Play the simulation using default values. What happes to the charged particle as it makes at least three loops in the field?
  • Adjust the mass of the particle to a new value and view the result from above and in 3D.
  • Adjust the particle charge and view the result.
  • Adjust the initial velocity in the x direction.
  • Adjust the initial velocity in the y direction.

Interactive Physics Simulations are provided at the GeoGebra site GeoGebra site.

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!