- To be able to calculate the magnetic field produced by a wire using the Biot-Savart Law.
- To be able to describe the magnetic fields due to simple current configurations: the field of a long wire, or the field of a circular loop of current.

Read through the course notes before watching the video. The course note files may also contain links to associated animations or interactive simulations.

Read sections 9.1 through 9.2:

Sources of Magnetic Fields (PDF - 1.9MB)

Read through the class slides. They explain all of the concepts from the module.

Do the Concept Questions first to make sure you understand the main concepts from this module. Then, when you are ready, try the Challenge Problems.

Watch the Problem Solving Help videos for insights on how to approach and solve problems related to the concepts in this module.

A rectangular wire loop of width *a* and height *b* carries a current *I*. Using the Biot-Savart Law, find the magnetic field in the center of the loop.

**Download this video:**

» iTunes U (MP4 - 21MB)

» Internet Archive (MP4 - 21MB)

A current loop with current *I* is made up of two semi-circles of radii *a* and *b*. The semi-circles have the same center. The circuit is completed by radial segments of wire between the ends of the semi-circles. What is the magnetic field at the center of the semi-circles?

**Download this video:**

» iTunes U (MP4 - 11MB)

» Internet Archive (MP4 - 11MB)

The visualizations linked below are related to the concepts covered in this module.

- The Magnetic Field of a Current Element

- The Magnetic Field of a Moving Positive Charge
- The Magnetic Field of a Moving Negative Charge
- Magnetic Field of Four Charges Moving in a Circle
- Integrating Around a Ring of Current
- The Ring of Current
- Two Wires in Parallel
- Two Wires in Series
- A Bar Magnet in the Earth's Magnetic Field
- The Magnetic Field of a Helmholtz Coil (aligned)

- Two Rings of Current Attracting
- The Magnetic Field of a Helmholtz Coil (anti-aligned)
- Two Rings of Current Repelling
- The TeachSpin(tm) Apparatus
- Magnet Oscillating Between Two Coils
- Magnet Suspended Between Two Coils

- The Magnetic Field of a Moving Positive Charge
- The Magnetic Field of a Current Element