AP Physics 2: Algebra-Based Flashcards: Electromagnetic Induction and Faraday's Law
Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026
Review key ideas with interactive flashcards. This set includes 11 cards to help you master important concepts.
What fundamental phenomenon causes an induced electric potential difference?
An induced electric potential difference (or emf) is caused by a change in the magnetic flux through a surface over a period of time.
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What fundamental phenomenon causes an induced electric potential difference?
An induced electric potential difference (or emf) is caused by a change in the magnetic flux through a surface over a period of time.
Define magnetic flux.
Magnetic flux describes the amount of the magnetic field component that is perpendicular to a given cross-sectional area.
What is the purpose of Lenz's Law?
Lenz's law is used to determine the direction of an induced emf and the resulting current that results from a changing magnetic flux.
If the magnetic flux into a coil of wire is increasing, what does Lenz's Law predict about the induced magnetic field?
Lenz's Law predicts the induced current will create its own magnetic field that opposes the increase, meaning the induced field will be in the opposite direction of the original field.
A loop of wire is in a uniform magnetic field. How can an emf be induced if the field strength (B) and the loop's area (A) remain constant?
An emf can be induced by rotating the loop, which changes its orientation relative to the field and thus changes the angle $\theta$ in the flux equation $\Phi_B = BA\cos\theta$.
What factor determines the magnitude of the induced emf?
The magnitude of the induced emf is determined by the *rate of change* of the magnetic flux ($|\frac{\Delta \Phi_B}{\Delta t}|$), not just the total change in flux.
According to Faraday's Law, what is the equation for the magnitude of the induced emf?
The magnitude of the induced emf is given by the equation $|\mathcal{E}| = |\frac{\Delta \Phi_B}{\Delta t}|$, representing the rate of change of magnetic flux.
A square loop of wire is pulled out of a uniform magnetic field at a constant velocity. What happens to the magnetic flux through the loop during this process?
The magnetic flux through the loop decreases because the cross-sectional area (A) of the loop that is inside the magnetic field is decreasing.
What does Faraday's Law describe?
Faraday's law describes the relationship between a changing magnetic flux and the resulting induced electromotive force (emf) in a system.
How is Lenz's Law represented in the full equation for Faraday's Law?
Lenz's Law is represented by the negative sign in the equation $\mathcal{E} = -\frac{\Delta \Phi_B}{\Delta t}$, indicating the induced emf opposes the change in magnetic flux.
What is the equation for calculating magnetic flux?
The equation is $\Phi_B = BA\cos\theta$, where B is the magnetic field magnitude, A is the area, and $\theta$ is the angle between the field and the normal to the surface.