Faraday’s law of induction

Definition

Faraday's Law of Induction states that a change in magnetic flux through a loop induces an electromotive force (EMF) in the wire. The induced EMF is directly proportional to the rate of change of magnetic flux.

5 Must Know Facts For Your Next Test

1. The formula for Faraday's Law is $\mathcal{E} = - \frac{d\Phi_B}{dt}$ where $\mathcal{E}$ is the induced EMF and $\Phi_B$ is the magnetic flux.
2. Lenz’s Law helps determine the direction of the induced current, stating that it will oppose the change in magnetic flux that produced it.
3. Magnetic flux ($\Phi_B$) is given by $\Phi_B = B \cdot A \cdot \cos(\theta)$, where $B$ is the magnetic field, $A$ is the area, and $\theta$ is the angle between them.
4. Faraday's Law applies to both closed loops and coils, with coils having an EMF multiplied by the number of turns ($N$): $\mathcal{E} = - N \frac{d\Phi_B}{dt}$.
5. Practical applications include generators, transformers, and inductors which all operate based on principles from Faraday’s Law.

Review Questions

• What does Faraday's Law of Induction state about changing magnetic flux?
• How does Lenz’s Law relate to Faraday’s Law when determining the direction of induced current?
• What factors influence magnetic flux according to its formula?

Related terms

Electromotive Force (EMF): The voltage generated by a changing magnetic field or other sources.

Magnetic Flux: A measure of the strength and orientation of a magnetic field over a certain area.

Lenz’s Law: States that an induced current will flow in a direction that opposes the change in magnetic flux that caused it.