AP Physics C: Electricity and Magnetism Unit 13 Topic 1: Electromagnetic induction (including Faraday’s Law and Lenz’s Law)

Electromagnetic induction (including Faraday’s Law and Lenz’s Law) belongs to Unit 13: Electromagnetic Induction. Electromagnetic induction occurs when changing magnetic flux produces an induced emf and current. In AP Physics C: Electricity and Magnetism, strong explanations connect diagrams, calculus relationships, fields, and energy or conservation principles.

Key relationships: Faraday's law relates induced emf to the rate of change of magnetic flux. Lenz's law gives the direction of the induced effect by opposing the flux change. Flux can change because magnetic field, area, or orientation changes.

Model to use: Identify the original flux, decide whether it increases or decreases, then choose the induced field direction that opposes the change. Define signs, surfaces, loops, paths, and coordinate directions before writing equations.

AP-style move: For direction questions, apply Lenz's law before using a right-hand rule for induced current. Show the symbolic setup first, then interpret the result with direction, sign, units, and physical meaning.