Electromagnetic Induction (Faraday's Law) – AP Physics 2 | ShowMeClass

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Electromagnetic Induction

AP Physics 2 · Unit 5: Magnetism

Learning Objectives

Apply Faraday's law: EMF = −dΦ/dt

Calculate magnetic flux: Φ = BAcosθ

Apply Lenz's law to determine induced current direction

Explore changing B, area, and angle scenarios

Key Equations

Lenz's Law

The induced current flows in a direction that opposes the change in magnetic flux that caused it.

If Φ increases → induced B opposes external B.
If Φ decreases → induced B supports external B.

Graph Colors

Φ — Magnetic Flux (Wb)

EMF — Induced Voltage (V)

I — Induced Current (A)

FaradayLenzFluxEMFAP Physics 2

Φ =—

EMF =—

I =—

Φ(t)

EMF(t)

I(t)

All

Scenario

B max (T) 0.5

Area A (cm²) 100

N (turns) 1

Loop R (Ω) 5

Frequency (Hz) 1.0

Speed 1×

Induction Values

📝 Quick Quiz▼

1. Faraday's law states EMF equals:

Φ × B −dΦ/dt B × A IR

2. Lenz's law says the induced current opposes:

The external B field The change in flux The applied voltage The loop's resistance

3. A loop rotating at constant ω in a uniform B produces:

Constant EMF Sinusoidal EMF Exponentially decaying EMF Zero EMF