D.4 Induction

Objective notes

6 learning objectives

—D.4.1 (HL)—Magnetic flux

• Magnetic flux: Φ=BA cosθ.

—D.4.2 (HL)—Faraday’s law

• Faraday’s law: changing magnetic flux induces emf ε=-NΔΦ/Δt.

—D.4.3 (HL)—Motional emf

• Motional emf in a straight conductor: ε=BvL.

—D.4.4 (HL)—Lenz’s law

• Lenz’s law gives induced emf direction and reflects energy conservation.

• Direction of induced emf opposes the change that produces it.

—D.4.5 (HL)—Rotating-coil emf

• Rotating coil in uniform magnetic field produces sinusoidal emf.

—D.4.6 (HL)—Rotation frequency and emf

• Increasing rotation frequency increases induced emf characteristics.