AP Physics C: Electricity and Magnetism Flashcards: Dielectrics
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.
State the equation that relates a material's permittivity (ε), the permittivity of free space (ε₀), and the dielectric constant (κ).
The relationship is given by the equation κ = ε / ε₀.
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State the equation that relates a material's permittivity (ε), the permittivity of free space (ε₀), and the dielectric constant (κ).
The relationship is given by the equation κ = ε / ε₀.
What is the primary effect on the electric field when a dielectric is placed between the plates of an isolated parallel-plate capacitor?
The electric field between the plates of the isolated capacitor decreases when a dielectric is placed between them.
What happens to a dielectric material when it is placed in an external electric field?
The material becomes polarized in the presence of the external electric field.
What is a dielectric material?
A dielectric is a material in which electric charges are not as free to move as they are in a conductor.
An isolated capacitor has an original electric field E₀. If a dielectric with constant κ is inserted, what is the new electric field E?
The new electric field is E = E₀ / κ, as derived from the equation κ = E₀ / E.
What is the dielectric constant (κ)?
The dielectric constant of a material relates the electric permittivity of that material (ε) to the permittivity of free space (ε₀).
How does the behavior of charges in a dielectric differ from that in a conductor?
In a dielectric, charges are not free to move throughout the material, whereas in a conductor, they move freely.
A material has a permittivity (ε) that is 5 times the permittivity of free space (ε₀). What is its dielectric constant (κ)?
The material's dielectric constant κ is 5, since κ = ε / ε₀ = 5ε₀ / ε₀ = 5.
Based on the equation κ = E₀ / E, what must be true about the value of κ for any dielectric material (not a vacuum)?
Since inserting a dielectric always decreases the electric field (E < E₀), the dielectric constant κ must be greater than 1.
How does inserting a dielectric change the properties of a capacitor?
Inserting a dielectric changes the capacitor's properties by polarizing the material and reducing the electric field between the plates.