AP Physics 2: Algebra-Based Flashcards: Capacitors
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 capacitor stores energy $U_C$ with charge Q and potential difference ΔV. If the charge is doubled to 2Q and the potential difference is also doubled to 2ΔV, what is the new stored energy?
Using the energy equation $U_{C}=\frac{1}{2}Q\Delta V$, the new energy will be $U_{C, new}=\frac{1}{2}(2Q)(2\Delta V) = 4(\frac{1}{2}Q\Delta V)$. The stored energy is quadrupled.
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A capacitor stores energy $U_C$ with charge Q and potential difference ΔV. If the charge is doubled to 2Q and the potential difference is also doubled to 2ΔV, what is the new stored energy?
Using the energy equation $U_{C}=\frac{1}{2}Q\Delta V$, the new energy will be $U_{C, new}=\frac{1}{2}(2Q)(2\Delta V) = 4(\frac{1}{2}Q\Delta V)$. The stored energy is quadrupled.
For a given capacitor, if the potential difference (ΔV) across it is doubled, what happens to the magnitude of the charge (Q) on each plate?
From the relationship $Q=C\Delta V$, if the capacitance (C) is constant and the potential difference (ΔV) is doubled, the charge (Q) on each plate must also double.
What is a parallel-plate capacitor?
A parallel-plate capacitor consists of two separated parallel conducting surfaces that can hold equal amounts of charge with opposite signs.
What is the equation for the electric potential energy stored in a capacitor?
The electric potential energy stored in a capacitor is described by the equation $U_{C}=\frac{1}{2}Q\Delta V$.
A parallel-plate capacitor's plates are moved farther apart, doubling the distance (d) between them. How does this change the capacitance (C)?
According to the equation $C=\kappa\epsilon_{0}\frac{A}{d}$, doubling the distance (d) will halve the capacitance (C), as they are inversely proportional.
How do the physical dimensions of a parallel-plate capacitor affect its capacitance?
The capacitance of a parallel-plate capacitor is proportional to the area of one of its plates and inversely proportional to the distance between its plates.
If the area (A) of a parallel-plate capacitor's plates is tripled, what is the effect on its capacitance (C)?
Based on the equation $C=\kappa\epsilon_{0}\frac{A}{d}$, tripling the area (A) will triple the capacitance (C), as they are directly proportional.
Define Capacitance (C).
Capacitance relates the magnitude of the charge (Q) stored on each plate to the electric potential difference (ΔV) created by the separation of those charges.
What two physical properties define a parallel-plate capacitor?
A parallel-plate capacitor is defined by its two parallel conducting surfaces and the separation distance between them.
What is the equation for the capacitance of a parallel-plate capacitor based on its geometry?
The equation is $C=\kappa\epsilon_{0}\frac{A}{d}$, where A is the plate area, d is the plate separation, κ is the dielectric constant, and ε₀ is the permittivity of free space.
What is the fundamental equation relating capacitance, charge, and potential difference?
The relationship is given by the equation $C=\frac{Q}{\Delta V}$, where C is capacitance, Q is the magnitude of the charge, and ΔV is the potential difference.