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Magnetic Field

  • A compass needle may be used to map the magnetic field lines.
  • An electric field exerts a force on a charge, whether the charge is stationary or moving. A magnetic field, however, exerts a force on a charge only if it is moving. The force is given by F = q v x B; it is the charge q times the cross product of the velocity v and magnetic field vectors.
  • Since the magnetic force is always perpendicular to the velocity, a magnetic does no work on a moving charge, and thus it does not change its speed.
  • If a charge, in a region where a uniform magnetic field exists, is given an initial velocity perpendicular to the field, then it will move in a circle.

Magnetic Field

Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.

AP Physics C: Electricity and Magnetism