AP Physics C: Electricity and Magnetism Flashcards: Magnetism and Moving Charges
Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026
Review key ideas with interactive flashcards. This set includes 10 cards to help you master important concepts.
How does the presence of an electric field affect the magnetic force on a moving charge?
It doesn't; a moving charged object in a region with both fields will experience independent forces from the magnetic field and the electric field.
Card 1 of 10
All Flashcards (10)
How does the presence of an electric field affect the magnetic force on a moving charge?
It doesn't; a moving charged object in a region with both fields will experience independent forces from the magnetic field and the electric field.
Under what two conditions will a charged object experience a force from a magnetic field?
A magnetic field will exert a force on a charged object only if the object is moving and its velocity has a component perpendicular to the field.
A stationary electron is placed in a strong, uniform magnetic field. What magnetic force does it experience?
The electron experiences zero magnetic force because the force equation $\vec{F}_{B}=q(\vec{v}\times\vec{B})$ requires the charge to have a non-zero velocity.
State the equation for the magnetic force ($\vec{F}_{B}$) on a charge (q) moving with velocity ($\vec{v}$) in a magnetic field ($\vec{B}$).
The equation for the magnetic force is $\vec{F}_{B}=q(\vec{v}\times\vec{B})$.
For the magnetic force on a moving charge to be at its maximum possible value, what must be the orientation between the charge's velocity and the magnetic field?
The charge's velocity vector must be perpendicular to the magnetic field vector for the force to be at its maximum.
What is the fundamental source of a magnetic field?
A single moving charged object produces a magnetic field.
Describe the dual relationship between moving charges and magnetic fields.
A moving charge both produces its own magnetic field and experiences a force when moving through an external magnetic field.
What mathematical operation determines the direction and magnitude of the magnetic force on a moving charge?
The magnetic force's magnitude and direction are determined by the cross-product of the charge's velocity vector and the magnetic field vector.
What two vector quantities are multiplied in the cross-product to find the magnetic force on a charge?
The magnetic force is found from the cross-product of the charge's velocity vector ($\vec{v}$) and the magnetic field vector ($\vec{B}$).
A proton is moving parallel to the direction of a uniform magnetic field. What is the magnitude of the magnetic force it experiences?
The magnetic force is zero because the cross-product of two parallel vectors (velocity and magnetic field) is zero.