AP Physics 2: Algebra-Based Flashcards: Magnetism and Current-Carrying Wires
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.
A wire carrying a non-zero current is placed in a non-zero magnetic field. Under what condition is the magnetic force on the wire zero?
The force is zero if the wire is parallel to the magnetic field, meaning the angle $\theta$ is 0 or 180 degrees, as $\sin(0^{\circ})=0$.
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A wire carrying a non-zero current is placed in a non-zero magnetic field. Under what condition is the magnetic force on the wire zero?
The force is zero if the wire is parallel to the magnetic field, meaning the angle $\theta$ is 0 or 180 degrees, as $\sin(0^{\circ})=0$.
If you double the current (I) in a long, straight wire, what happens to the magnetic field strength (B) at a fixed distance (r)?
The magnetic field strength (B) also doubles, because it is directly proportional to the current (I).
What is the fundamental magnetic property of a wire with an electric current flowing through it?
A current-carrying wire produces a magnetic field in the space around it.
At what angle ($\theta$) between a current-carrying wire and a magnetic field is the magnetic force on the wire maximized?
The force is maximized when the angle is 90 degrees, as $\sin(90^{\circ}) = 1$.
What four factors determine the magnitude of the magnetic force on a current-carrying wire?
The force magnitude is proportional to the current, the length of the wire in the field, the magnetic field's magnitude, and the angle between the current and the field.
What is the Right-Hand Rule used for in the context of a current-carrying wire?
The right-hand rule is used to determine the direction of the magnetic field created by a current-carrying wire.
How does the distance from a long, straight wire affect the strength of the magnetic field it produces?
The magnitude of the magnetic field is inversely proportional to the perpendicular distance from the central axis of the wire.
A current-carrying wire is placed in a magnetic field. If the angle between the wire and the field changes from 90° to 30°, how does the force on the wire change?
The force is reduced by half, because $\sin(30^{\circ}) = 0.5$, which is half the value of $\sin(90^{\circ}) = 1$.
What is the equation for the magnitude of the magnetic force ($F_B$) on a straight wire of length $\ell$ in a uniform magnetic field B?
The equation is $F_B = I\ell B\sin\theta$, where $\theta$ is the angle between the direction of the current and the magnetic field.
What happens to a current-carrying wire when it is placed within an external magnetic field?
The magnetic field exerts a force on the current-carrying wire.
What is the equation for the magnitude of the magnetic field (B) produced by a long, straight wire carrying current (I) at a distance (r)?
The equation is $B= rac{\mu_0}{2\pi}\frac{I}{r}$.