Unit 5: Magnetism and Electromagnetic Induction

Welcome to Unit 5! Here we'll take a look at how magnets work, as well as investigate the relationship between electricity and magnetism. This topic is the foundation of most of our modern world. It allows us to create electricity, use electric motors, and makes speakers, computers, and cell phones all work. As far as the AP exam is concerned, this unit covers approximately 10% of the exam questions. If you'd like some practice problems, check out the AP Classroom Unit 5 Progress Check which has 35 MCQ and 2 FRQ for you to try

If you look around, most of the objects you encounter in your daily life aren't magnetic. This shouldn't be a surprise though, because creating a magnet requires a very specific set of both micro and macroscopic features. To begin with, we've known since the 1920's that a moving charged object can create a magnetic field and become its own tiny magnet. For reasons that we won't get into here, it's primarily the electrons that determine the overall magnetic field of the atom. These electrons can cause natural magnets to occur in elements with half-filled energy levels.

Electromagnetic Induction is the process of using magnetic fields to produce a voltage. If that voltage is produced in a complete circuit, it can create a current. We've seen in the previous section that current moving through a wire creates a magnetic field, all we're doing here is reversing that process.