Electromagnetic Induction and Faraday's Law - AP Physics 2

Tesla (T). Measures magnetic field intensity or flux density.

The induced emf is equal to the negative rate of change of magnetic flux. This is the fundamental principle governing electromagnetic induction.

$\text{Φ}_B = 6 \text{Wb}$. Use $\Phi_B = BA$: $2 \times 3 = 6 \text{Wb}$.

Magnetic flux is directly proportional to the area. Larger area allows more field lines to pass through.

To measure the induced current. Detects and measures small currents in induction experiments.

Resistance of the coil. Resistance affects current, not the induced emf magnitude.

Increases magnetic flux and induces greater emf. Larger area captures more magnetic flux for induction.

Opposition to change in magnetic flux (Lenz's Law). Represents Lenz's Law - induced effects oppose the change.

Emf is maximized when the coil is perpendicular to the magnetic field. Maximum flux change occurs when perpendicular to field lines.

A closed loop allows an induced current to flow. Provides a complete path for induced current circulation.

Weber (Wb). Named after Wilhelm Weber, equivalent to $\text{T}\cdot\text{m}^2$.

Electric generators. Converts mechanical energy to electrical energy using induction.

No change in flux, no induced emf. Uniform field means no spatial flux variation.

The direction of the induced current opposes the change in magnetic flux. Explains the negative sign in Faraday's Law equation.

Magnetic flux is the product of the magnetic field and the area through which it passes. Quantifies how much magnetic field passes through a surface.

Product of the magnetic flux and the number of turns in a coil. Total magnetic flux linking all turns of a coil.

Rate of change of magnetic flux. Faster flux changes produce larger induced emf magnitudes.

Magnetic flux increases. More field lines pass through the same area.

Volt (V). Same unit as voltage since emf represents induced potential difference.

$\text{emf} = -2.5 \text{V}$. Use $\text{emf} = -\frac{\Delta\Phi_B}{\Delta t} = -\frac{5-10}{2} = -2.5 \text{V}$.

Inducing emf in one coil due to change in current in another. Current change in one coil induces emf in nearby coil.

Electromagnetic induction. Uses changing magnetic flux to transfer energy between coils.

It changes the magnetic flux through the coil. Motion changes the magnetic flux through the coil.

No change in magnetic flux and no induced emf. Constant field means $\frac{d\Phi_B}{dt} = 0$, so no emf.

More turns increase the induced emf. Each turn contributes to the total induced emf.

Electromotive force. The potential difference induced by changing magnetic flux.

A solenoid can enhance the magnetic field and hence induce emf. Multiple turns multiply the induced emf effect.

$\text{emf} = 3 \text{V}$. Apply Faraday's Law: $\text{emf} = -(-3) = 3 \text{V}$.

A voltage generated by changing magnetic fields. The electrical potential difference created by changing magnetic flux.