12.6: Electromagnetic Induction and Faraday’s Law

Describe the induced electric potential difference resulting from a change in magnetic flux.

12.6.A.1 Magnetic flux is a measurement of the magnitude of the component of a magnetic field that is perpendicular to a cross sectional area.

12.6.A.2 Magnetic flux through a surface is proportional to the magnitude of the magnetic field perpendicular to the surface and the cross-sectional area of the surface.

• 12.6.A.2.i The area vector is defined to be perpendicular to the plane of the surface and directed outward from a closed surface.

• 12.6.A.2.ii The sign of the magnetic flux indicates if the magnetic field is directed into or out of the given area.

12.6.A.3 Faraday’s law describes the relationship between changing magnetic flux and the resulting induced emf within a system. 

12.6.A.4 Lenz’s law is used to determine the direction of an induced emf resulting from a changing magnetic flux.

• 12.6.A.4.i The induced emf generates a current that creates a magnetic field that opposes the change in magnetic flux.

• 12.6.A.4.ii The right-hand rule is used to determine the relationships between current, emf, and magnetic flux.