Unit V On-a-Page


All of the homework for this unit can be found at this link.

Given that this unit is short, so is the homework!


  • Only moving charges (i.e. currents) generate and feel magnetic fields
  • The field is “real” and the key object (just like for electricity)
  • Moving charges make fields which can then exert forces on other moving charges
  • Use your right hand: thumb in current (  \vec{I} or q \vec {v} ), fingers in  \vec{B}
  • For the direction of a magnetic field, fingers curl in direction of  \vec{B}
  • \vert \vec{B} \vert = \frac{I \mu_0}{2 \pi r}
  • \mu_0 is another universal constant like hc\varepsilon_0and \mu_0 = 4 \pi \times 10^{-7} \frac{N} {A^2}
  • For the force, palm “pushes” in the direction of  \vec{F}
  • F = qVBsin\theta or F = ILBsin\theta
  • Result is particles in uniform  \vec{B} move in circles!!


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Physics 132: What is an Electron? What is Light? by Roger Hinrichs, Paul Peter Urone, Paul Flowers, Edward J. Neth, William R. Robinson, Klaus Theopold, Richard Langley, Julianne Zedalis, John Eggebrecht, and E.F. Redish is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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