AP Physics 2 Unit 10 Review: Electric Force, Field, and Potential

Q: What's on the AP Physics 2 Unit 10 progress check (MCQ and FRQ)?

The AP Physics 2 Unit 10 progress check includes both MCQ and FRQ parts drawn from all 7 unit topics. The MCQ section tests concepts like electric charge, electric force, electric fields, and electric potential. The FRQ part asks you to apply those ideas quantitatively, often involving capacitors or conservation of electric energy. Practice with matched questions at AP Physics 2 Unit 10 .

Q: How do I practice AP Physics 2 Unit 10 FRQs?

AP Physics 2 Unit 10 FRQs most often pull from electric potential, electric fields, and capacitors. Questions typically ask you to derive or calculate quantities, draw or interpret field diagrams, and explain energy relationships using conservation of electric energy. To practice, work through problems that require you to connect multiple topics, like linking electric potential energy to capacitor charge storage, then check your reasoning step by step. Find practice FRQs at AP Physics 2 Unit 10 .

Q: Where can I find AP Physics 2 Unit 10 practice questions?

For AP Physics 2 Unit 10 practice questions, including multiple-choice and practice test sets, head to AP Physics 2 Unit 10 . You'll find MCQs covering electric charge, electric force, electric fields, electric potential, and capacitors, plus full practice test questions organized by topic so you can target weak spots.

Q: How should I study AP Physics 2 Unit 10?

Start with electric charge and electric force so Newton's laws feel familiar in an electrostatics context, then build toward electric potential and capacitors. Sketch field diagrams for every scenario you encounter. Practice moving between force, field, potential energy, and electric potential, since AP Physics 2 Unit 10 FRQs often require all four in one problem. After each topic, do a short set of MCQs to catch gaps early, then revisit conservation of electric energy last since it ties everything together. Organize your review at AP Physics 2 Unit 10 .

15–18% of AP multiple choice
7 topics
AP exam review verified for 2027

Unit 10 covers electric charge and Coulomb's law, conservation and transfer of charge, electric fields and field maps, electric potential energy, electric potential and equipotential lines, parallel-plate capacitors, and conservation of electric energy for moving charges.

Fiveable's AP Physics 2 Unit 10 review covers 7 topics, with guided practice questions for the unit.

start with 10.1 start unit practice

AP Physics 2 unit 10 topics

10.1

Electric Charge and Electric Force

Introduces charge as a fundamental property, the elementary charge e, the point charge model, Coulomb's law |F| = k|q1 q2|/r^2, electric permittivity, and the comparison of electric and gravitational forces.

open guide

10.2

Conservation of Electric Charge and the Process of Charging

Covers conservation of charge, charging by friction, contact, and induction, induced charge separation in neutral objects, and grounding.

open guide

10.3

Electric Fields

Defines the electric field E = F/q, covers vector superposition of fields from multiple charges, field line maps, and the distinct field behavior inside conductors versus insulators in electrostatic equilibrium.

open guide

10.4

Electric Potential Energy

Defines U_E = kq1q2/r for a pair of point charges, explains the sign convention, and extends to multi-charge systems using pairwise summation.

open guide

10.5

Electric Potential

Introduces electric potential V = kq/r as a scalar, scalar superposition, potential difference delta V = delta U_E / q, equipotential lines, and the relationship |E| = |delta V / delta r|.

open guide

10.6

Capacitors

Covers parallel-plate capacitor geometry, C = Q/delta V, C = kappa epsilon_0 A/d, the effect of dielectrics, the uniform field between plates, and stored energy U_C = (1/2) Q delta V.

open guide

10.7

Conservation of Electric Energy

Applies conservation of energy to charged particles moving through potential differences using delta U_E = q delta V and delta K = -delta U_E, with attention to sign conventions for positive and negative charges.

open guide

Practice AP Physics 2 unit 10 questions

Try AP-style questions on unit 10, then use the review notes below for anything you miss.

Example stimulus-based MCQs

open all practice

diagram

Stimulus-based practice question

A hollow conducting spherical shell of inner radius R and outer radius 2R carries a net charge of +2Q. A point charge of −Q is placed at the center of the shell. The figure shows a cross-section of the shell with the point charge at the center.

answer in practice

Question

A student claims the electric field for r < R is zero because a conducting shell shields the interior. Which choice best evaluates that claim?

Correct, because the shell redistributes charge to cancel the cavity field.

Correct, because a Gaussian surface in the conductor encloses zero charge.

Incorrect, because the central charge −Q creates a field in the cavity.

Incorrect, because the cavity field is zero only for a positive point charge.

diagram

Stimulus-based practice question

Two identical neutral metal spheres, P and Q, rest on insulating stands and are in contact. A negatively charged rod is brought near sphere P, as shown. While the rod remains in place, the spheres are separated. The rod is then removed.

answer in practice

Question

Which of the following correctly compares the final net charges on sphere P (Q_P) and sphere Q (Q_Q) after the rod is removed?

Q_P is negative and Q_Q is positive, with |Q_P| = |Q_Q|.

Q_P is negative and Q_Q is positive, with |Q_P| > |Q_Q|.

Q_P is neutral and Q_Q is neutral, because the rod never touched either sphere.

Q_P is positive and Q_Q is negative, with |Q_P| = |Q_Q|.

Example FRQs

open all FRQs

FRQ

480 V capacitor with a dielectric: sphere forces, capacitance, and energy

2. Two large, parallel conducting plates of area $A = 0.040\ \text{m}^2$ are separated by a distance $d = 6.0× 10^{-3}\ \text{m}$ , as shown in Figure 1. The plates are initially uncharged and are connected to a battery that maintains a potential difference of $\Delta V = 480\ \text{V}$ with the top plate at higher potential. The region between the plates is initially air, which can be treated as vacuum with permittivity $\varepsilon_0 = 8.85× 10^{-12}\ \text{F/m}$ . A small insulating sphere of mass $m = 2.0× 10^{-4}\ \text{kg}$ carrying charge $q = +3.0× 10^{-9}\ \text{C}$ is released from rest midway between the plates. Take $g = 9.8\ \text{m/s}^2$ .

Figure 1. Parallel-plate capacitor connected to a 480 V battery with a positively charged insulating sphere released midway between the plates.

Figure dot. Force diagram. Dot represents the center of mass of the charged insulating sphere just after release.

On the dot shown in Figure dot, representing the charged sphere just after it is released, draw and label the forces that are exerted on the sphere. Each force must be represented by a distinct arrow starting on, and pointing away from, the dot.

Derive an expression for the magnitude of the electric field $E$ between the plates in terms of $\Delta V$ and $d$ . Begin your derivation by writing a fundamental physics principle or an equation from the reference information. Then use your result to derive an expression for the magnitude of the net force on the sphere in terms of $q$ , $\Delta V$ , $d$ , $m$ , and $g$ .

Figure 2. Axes for electric potential V as a function of vertical position y between the plates (y=0 at bottom plate, y=d at top plate).

On the axes provided in Figure 2, sketch the electric potential $V(y)$ between the plates as a function of vertical position $y$ , where $y = 0$ at the bottom plate and $y = d$ at the top plate. Clearly indicate on your sketch the values $V(0)$ and $V(d)$ , and draw an arrow on your sketch to indicate the direction of the electric field.

Indicate whether each of the following quantities increases, decreases, or remains the same when the dielectric is inserted while the battery stays connected. A dielectric slab of thickness $t = 6.0× 10^{-3}\ \text{m}$ (equal to the plate separation) and relative permittivity $\kappa = 4.0$ is inserted to completely fill the region between the plates while the battery remains connected and maintains $\Delta V = 480\ \text{V}$ . The sphere is again placed midway between the plates and released from rest.

Given values: $A = 0.040\ \text{m}^2$ , $d = 6.0× 10^{-3}\ \text{m}$ , $\Delta V = 480\ \text{V}$ , $\varepsilon_0 = 8.85× 10^{-12}\ \text{F/m}$ , $\kappa = 4.0$ , $m = 2.0× 10^{-4}\ \text{kg}$ , $q = +3.0× 10^{-9}\ \text{C}$ , $g = 9.8\ \text{m/s}^2$ .

The magnitude of the electric field between the plates
Increases
Decreases
Remains the same

The magnitude of the charge on the top plate
Increases
Decreases
Remains the same

The energy stored in the capacitor
Increases
Decreases
Remains the same

Briefly justify each answer. Your justification must reference conservation of charge and/or the relationship between $\Delta V$ , $E$ , capacitance, and energy. Then calculate the new energy stored in the capacitor after the dielectric is inserted.

write this FRQ more Representations FRQs in this unit

FRQ

Dielectric permittivity determination in parallel-plate capacitors

3. In Experiment 1, a student is given a parallel-plate capacitor with square conducting plates. The plates can be separated by an adjustable distance d. The region between the plates can be either air or completely filled with a slab of dielectric material. The student is asked to determine the permittivity of the dielectric material and relate the results to electric field and electric potential in the capacitor.

Describe a procedure for collecting data that would allow the student to determine the permittivity $\varepsilon$ of the dielectric material. In your description, include the measurements to be made. Include any steps necessary to reduce experimental uncertainty.

Describe how the collected data could be analyzed to determine $\varepsilon$ . Include references to appropriate equations and to relationships between measured and known quantities.

Figure 1. Parallel-plate capacitor circuit for measuring charge q and potential difference ΔV with adjustable plate separation d and optional dielectric slab filling the gap.

Figure 2. Blank graphing grid for a straight-line plot used to determine capacitance C from measurements of charge q and potential difference ΔV.

DeltaV (V)	q (x10^-8 C)
50.0	0.46
100.0	0.91
150.0	1.36
200.0	1.82
250.0	2.27

In Experiment 2, the student sets the plate separation to $d = 3.00× 10^{-3}\ \text{m}$ and fully inserts the dielectric so it completely fills the gap between the plates. For each trial, the student charges the capacitor to an absolute potential difference $\Delta V$ , then disconnects the power supply and uses the electrometer to measure the charge $q$ on one plate. Table 1 contains the data collected.

Indicate two quantities, either measured quantities from Table 1 or additional calculated quantities, that could be graphed to produce a straight line that could be used to determine the capacitance $C$ of the capacitor.

Vertical axis: Horizontal axis:

ii.

On Figure 2, create a graph of the quantities indicated in part C(i) that can be used to determine $C$ .

•

Use Table 2 to record the data points or calculated quantities that you will plot.

•

Clearly label the axes, including units as appropriate.

•

Plot the points you recorded in Table 2.

iii.

Draw a best-fit line for the data graphed in part C(ii).

Using the best-fit line that you drew in part C(iii), calculate an experimental value for the capacitance $C$ . Using the best-fit line from part C(iii), the student determines that the slope of the graph is $9.10× 10^{-11}\ \text{C/V}$ .

write this FRQ more Experimental Design FRQs in this unit

FRQ

Charge redistribution and electrostatic forces

1. Two small conducting spheres, Sphere A and Sphere B, are mounted on insulating stands and can be treated as point charges, as shown in Figure 1. Sphere A has mass $m_A = 4.0× 10^{-3}\ \text{kg}$ and initial charge $q_{A,i} = +6.0\ \text{nC}$ . Sphere B has mass $m_B = 4.0× 10^{-3}\ \text{kg}$ and initial charge $q_{B,i} = -2.0\ \text{nC}$ . The centers of the spheres are separated by a distance $r = 0.40\ \text{m}$ in air, which may be treated as vacuum with permittivity $\varepsilon_0 = 8.85× 10^{-12}\ \text{F/m}$ . The spheres are then touched together and separated again so that the final charges on the two identical conducting spheres are equal. Ignore air breakdown and assume the spheres are small compared with $r$ .

Figure 1. Two identical small conducting spheres on insulating stands separated by r = 0.40 m along the +x direction.

Figure 2. Force-direction vectors at Sphere A due to Sphere B (electric and gravitational).

Figure 3. Direction of the net electric field at the midpoint P between two spheres.

Complete the following tasks in Figures 2 and 3.

•

Indicate the direction of the electric force exerted on Sphere A by Sphere B in Figure 2.

•

Indicate the direction of the gravitational force exerted on Sphere A by Sphere B in Figure 2.

•

Indicate the direction of the net electric field at the midpoint point P between the spheres in Figure 3.

ii.

After the spheres are touched together and separated, the final charges on the identical conducting spheres are equal.

Derive an expression for the magnitude of the net electric field at the midpoint point P after the spheres are separated, in terms of $\varepsilon_0$ , $r$ , and the initial charges $q_{A,i}$ and $q_{B,i}$ . Begin your derivation by writing a fundamental physics principle or an equation from the reference information.

Figure 4. Parallel-plate capacitor (A = 0.020 m^2, d = 2.0×10^−3 m) connected to a 120 V battery; dielectric slab inserted to fully fill the plate gap.

Indicate whether the magnitude of the electric field between the plates increases, decreases, or remains the same after the dielectric is inserted. A parallel-plate capacitor has plate area $A = 0.020\ \text{m}^2$ and plate separation $d = 2.0× 10^{-3}\ \text{m}$ , as illustrated in Figure 4. The capacitor is connected to a battery that maintains a constant potential difference $\Delta V = 120\ \text{V}$ . The capacitor is initially filled with vacuum (permittivity $\varepsilon_0 = 8.85× 10^{-12}\ \text{F/m}$ ). A dielectric slab with dielectric constant $\kappa = 3.0$ is then inserted fully between the plates while the capacitor remains connected to the battery.

Increases
Decreases
Remains the same

Justify your answer.

write this FRQ more Mathematical Routines FRQs in this unit

AP Physics 2 unit 10 practice test

A timed, AP-style test built only from unit 10 questions — multiple choice plus free response, scored with AI feedback. Use the standard format or build your own.

Take the unit 10 practice test

Unit 10 review notes

10.1

Electric Charge and Coulomb's Law

Charge is a fundamental property of matter, quantized in units of the elementary charge e = 1.602 x 10^-19 C. Protons carry +e, electrons carry -e, and neutrons carry no charge. Coulomb's law gives the magnitude of the electrostatic force between two point charges: |F_E| = k|q1 q2|/r^2, where k = 8.99 x 10^9 N m^2/C^2. The force is attractive for opposite signs and repulsive for like signs, and it falls off as 1/r^2. Electric permittivity epsilon_0 appears in the equivalent form |F_E| = |q1 q2| / (4 pi epsilon_0 r^2). For any object with both mass and charge, the gravitational force is almost always negligible compared to the electrostatic force at small scales; gravity dominates at large scales only because macroscopic objects are nearly electrically neutral.

Elementary charge: e = 1.602 x 10^-19 C; the smallest indivisible unit of charge, carried by a proton (+e) or electron (-e).
Point charge model: Treats a charged object as if all its charge is concentrated at a single point, valid when the object's size is negligible compared to the distances involved.
Coulomb's law: |F_E| = k|q1 q2|/r^2; force is proportional to each charge and inversely proportional to the square of the separation distance.
Electric permittivity: epsilon_0 = 8.85 x 10^-12 F/m; measures how easily a medium is polarized; appears in the denominator of Coulomb's law as 4 pi epsilon_0.
Electric vs. gravitational force: Both follow inverse-square laws, but electrostatic forces can be attractive or repulsive while gravity is always attractive; electrostatic forces handle at atomic and molecular scales.

If the distance between two charges doubles, by what factor does the electrostatic force change? (Answer: it decreases by a factor of 4, since force is proportional to 1/r^2.)

Property	Gravitational Force	Electrostatic Force
Source	Mass	Electric charge
Direction	Always attractive	Attractive or repulsive
Law	F = Gm1m2/r^2	F = k\|q1 q2\|/r^2
Dominates at	Large (astronomical) scales	Small (atomic/molecular) scales

10.2

Conservation of Charge and Charging Methods

The net charge of an isolated system never changes; any change in a system's charge requires a transfer of charge to or from its surroundings. Charging by friction transfers electrons between materials based on their positions in the triboelectric series. Charging by contact (conduction) transfers electrons when objects touch. Charging by induction redistributes charge within a neutral object without direct contact, and grounding allows excess charge to flow to or from Earth, leaving the object with a net charge. Induced charge separation can occur in neutral objects and does not change their net charge.

Conservation of charge: The total charge of an isolated system is constant; charge is neither created nor destroyed, only transferred.
Charging by friction: Electrons transfer between two materials rubbed together; the material that gains electrons becomes negative, the one that loses electrons becomes positive.
Charging by induction: A nearby charged object redistributes charges in a neutral conductor without touching it; grounding during induction leaves the conductor with a net charge opposite to the inducing charge.
Induced charge separation: The electrostatic force from an external charge rearranges charges within a neutral object, creating a polarized distribution without changing the net charge.
Grounding: Connecting a charged object to Earth allows charge to flow until the object reaches electrical neutrality or a defined charge state.

A neutral metal sphere is brought near a positively charged rod without touching. The near side of the sphere becomes negative. If the sphere is then grounded while the rod is still nearby, what is the sphere's net charge after the ground connection is removed and the rod is taken away? (Answer: the sphere is left with a net negative charge.)

10.3

Electric Fields

The electric field at a point is defined as E = F_E / q, where q is a small positive test charge that does not disturb the field. Fields point away from positive source charges and toward negative source charges. For a single point charge, E = kq/r^2. The net field from multiple charges is the vector sum of individual fields (superposition). In electrostatic equilibrium, the field inside a solid conductor is zero and the field at the surface is perpendicular to the surface; all excess charge resides on the surface. Inside an insulator, the field can be nonzero. Electric field line maps show direction and relative magnitude: denser lines indicate stronger fields.

Electric field definition: E = F_E / q; the force per unit positive test charge at a point in space; units are N/C.
Superposition principle: The net electric field at any point is the vector sum of the fields produced by each individual charge.
Field inside a conductor: Zero in electrostatic equilibrium; any excess charge distributes on the outer surface, and the field at the surface is perpendicular to it.
Field inside an insulator: Can be nonzero because charge is distributed throughout the volume, not just on the surface.
Electric field lines: Visual representation of the field; direction shows force on a positive test charge, and line density indicates field magnitude.

Two equal positive charges are placed 0.2 m apart. Where along the line connecting them is the net electric field zero? (Answer: at the midpoint, by symmetry, since the two equal fields point in opposite directions and cancel.)

10.4

Electric Potential Energy

The electric potential energy of a two-charge system equals the work an external agent must do to bring the charges from infinitely far apart to their current separation: U_E = kq1q2/r. The sign of U_E depends on the product q1q2: positive for like charges (energy stored in repulsion) and negative for opposite charges (energy released in attraction). For a system of more than two charges, sum the potential energy of every unique pair: U_total = sum of k qi qj / r_ij for all i < j. The reference point is U_E = 0 at infinite separation.

Electric potential energy formula: U_E = kq1q2/r; positive when charges have the same sign, negative when they have opposite signs.
Work to assemble charges: U_E equals the work done by an external force to bring charges from infinity to their current positions against (or with) the electric force.
Pairwise superposition: For a system of N charges, total U_E is the sum of kqiqj/rij for every unique pair; each pair is counted once.
Sign convention: Negative U_E means the configuration is energetically favorable (charges attracted); positive U_E means work was done against repulsion.

Three charges +q, +q, and -q are placed at the corners of an equilateral triangle with side length d. What is the sign of the total electric potential energy of the system? (Hint: identify the three pairs and their signs, then sum.)

10.5

Electric Potential and Equipotential Lines

Electric potential V is the electric potential energy per unit charge at a point: V = U_E / q. For a point charge, V = kq/r. Because potential is a scalar, contributions from multiple charges add algebraically: V = k sum(qi/ri). Potential difference delta V = delta U_E / q tells how much energy per coulomb changes when a charge moves between two points. The average electric field magnitude between two points is |E| = |delta V / delta r|, so field vectors point from high to low potential. Equipotential lines (isolines) connect points of equal V and are always perpendicular to field vectors. No work is done moving a charge along an equipotential. Conductors in electrostatic equilibrium are equipotential surfaces.

Electric potential: V = U_E / q; scalar quantity in volts (V = J/C); for a point charge, V = kq/r.
Scalar superposition: Total potential from multiple charges is V = k sum(qi/ri); add algebraically, not as vectors.
Potential difference: delta V = delta U_E / q; the change in potential energy per coulomb when a charge moves between two points.
Equipotential lines: Lines of equal electric potential; always perpendicular to electric field vectors; no work is done moving a charge along them.
Field-potential relationship: |E| = |delta V / delta r|; the electric field points in the direction of decreasing potential.

A positive charge moves from a region of high potential to low potential. Does its electric potential energy increase or decrease? Does it speed up or slow down? (Answer: U_E decreases; kinetic energy increases; the charge speeds up.)

Feature	Electric Field	Electric Potential
Type	Vector	Scalar
Formula (point charge)	E = kq/r^2	V = kq/r
Superposition	Vector sum	Algebraic sum
Relationship	Points from high to low V	Decreases in direction of E
Equipotentials	Perpendicular to field lines	Lines/surfaces of constant V

10.6

Capacitors

A parallel-plate capacitor consists of two conducting plates that store equal and opposite charge Q separated by a gap d. Capacitance is defined as C = Q / delta V and depends only on geometry and material: C = kappa epsilon_0 A / d, where kappa is the dielectric constant of the material between the plates, A is the plate area, and d is the separation. The uniform electric field between the plates is E = Q / (kappa epsilon_0 A). Inserting a dielectric increases capacitance by reducing the effective field through induced polarization. Energy stored in a capacitor is U_C = (1/2) Q delta V = (1/2) C (delta V)^2 = Q^2 / (2C).

Capacitance definition: C = Q / delta V; the ratio of stored charge to the potential difference across the plates; units are farads (F).
Parallel-plate capacitance: C = kappa epsilon_0 A / d; increases with larger plate area, decreases with larger gap, increases with higher dielectric constant.
Dielectric constant kappa: A dimensionless factor greater than 1 that multiplies epsilon_0 when a material fills the gap; increases capacitance by reducing the electric field for a given charge.
Stored energy: U_C = (1/2) Q delta V = (1/2) C (delta V)^2 = Q^2 / (2C); energy is stored in the electric field between the plates.
Uniform field between plates: E = Q / (kappa epsilon_0 A); constant in magnitude and direction between ideal parallel plates, enabling projectile-like analysis of charged particles.

A capacitor is charged to voltage delta V and then disconnected from the battery. If the plate separation is doubled, what happens to the capacitance, the voltage, and the stored energy? (Answer: C halves, delta V doubles since Q is fixed, and U_C doubles.)

10.7

Conservation of Electric Energy

When a charged object moves between two points with different electric potentials, its electric potential energy changes by delta U_E = q delta V. Because the electrostatic force is conservative, energy is conserved: any decrease in U_E appears as an increase in kinetic energy, and vice versa. For a charge moving freely in an electric field, delta K = -delta U_E. This is the electric analog of conservation of mechanical energy. Sign conventions matter: a positive charge moving from high to low potential loses potential energy and gains kinetic energy; a negative charge moving from high to low potential gains potential energy and loses kinetic energy.

Energy change formula: delta U_E = q delta V; the change in electric potential energy equals the charge times the potential difference.
Conservation of energy: delta K + delta U_E = 0 for a charge moving freely in an electric field; kinetic and potential energy trade off.
Sign convention for charges: Positive charges accelerate from high to low potential (losing U_E, gaining K); negative charges accelerate from low to high potential.
Work done by electric field: W = -delta U_E = q delta V; positive work by the field increases kinetic energy.

An electron (charge -e) moves from a point at V = 0 V to a point at V = +100 V. Does it speed up or slow down? (Answer: delta U_E = (-e)(+100) < 0, so U_E decreases and K increases; the electron speeds up.)

Key terms

Term	Definition
conservation of charge	The net charge of an isolated system remains constant; any change in a system's charge requires a transfer of charge to or from its surroundings.
induced charge separation	The redistribution of charges within a system caused by the electrostatic force from a nearby charged object, resulting in polarization without changing the system's net charge.
superposition principle	The net electric field or force at a point due to multiple charges is the vector sum of the individual contributions; electric potential adds as a scalar sum.
electrostatic equilibrium	A state in which excess charge on a conductor is stationary, the electric field inside the conductor is zero, and all excess charge resides on the outer surface.
surface charge distribution on conductors	In electrostatic equilibrium, all excess charge on a solid conductor resides on the outer surface, with none in the interior.
equipotential lines	Lines connecting points of equal electric potential; always perpendicular to electric field vectors; no work is done moving a charge along them.
equipotential surface	A surface on which every point is at the same electric potential; conductors in electrostatic equilibrium are equipotential surfaces.
charge-voltage relationship	C = Q / delta V; defines capacitance as the ratio of stored charge to the potential difference across the capacitor plates.
work-energy theorem	In electrostatics, the net work done by the electric force on a charge equals its change in kinetic energy; combined with delta U_E = q delta V, this gives delta K = -delta U_E.
Work (W)	Energy transferred by a force; the work done by the electric force on a charge moving through a potential difference is W = q delta V = -delta U_E.
Electroscope	A device that detects electric charge; its leaves spread apart when charged and return together when charge is removed or neutralized.

How to review unit 10

Topics students miss most

Miss rates come from Fiveable multiple-choice practice.

10.7

Conservation of Electric Energy

52%109 tries

10.1

Electric Charge and Electric Force

45%530 tries

10.2

Conservation of Electric Charge and the Process of Charging

26%284 tries

Common unit 10 mistakes

Treating electric potential like a vector

Electric potential V is a scalar. When finding the total potential from multiple charges, add the values algebraically (with signs), not as vectors. Only electric field and electric force require vector addition.

Confusing electric potential with electric potential energy

V = U_E / q is the energy per unit charge at a point in space; it does not depend on a test charge. U_E = qV is the actual energy of a specific charge q at that location. Mixing up the two leads to errors in both calculation and reasoning.

Ignoring the sign of q in energy problems

In delta U_E = q delta V, the sign of q matters. A negative charge moving from low to high potential has a negative delta U_E, meaning it gains kinetic energy. Always substitute the signed value of q, not just its magnitude.

Assuming the field inside a conductor is always zero

The field inside a conductor is zero only in electrostatic equilibrium. Inside an insulator, the field can be nonzero because charge is distributed throughout the volume, not just on the surface.

Applying Coulomb's law to extended charge distributions

Coulomb's law in the form F = kq1q2/r^2 applies to point charges or spherically symmetric distributions. For other geometries, use field and potential reasoning rather than direct Coulomb's law calculations.

How this unit shows up on the AP exam

Translating between representations

AP Physics 2 free-response questions frequently ask you to move between field vector maps, equipotential maps, force diagrams, and energy bar charts for the same physical situation. Practice reading a field map and constructing the corresponding equipotential diagram, or using delta U_E = q delta V to fill in an energy bar chart for a charge moving between two labeled equipotentials.

Qualitative reasoning about charge and field changes

Multiple-choice and free-response items often change one variable in a capacitor or charge configuration and ask you to predict the effect on other quantities. Be ready to reason through how doubling plate separation, inserting a dielectric, or changing the sign of a charge affects C, Q, delta V, E, U_C, and the force on a nearby charge, using the relevant equations as reasoning tools rather than just calculation shortcuts.

Conservation of energy for charged particles

A common task type presents a charged particle moving between two points of known potential and asks for its final speed or kinetic energy change. The key skill is correctly applying delta U_E = q delta V with the signed charge value, then using delta K = -delta U_E. Watch for negative charges, which behave opposite to positive charges when moving through the same potential difference.

More ways to review

Topic study guides

Open the individual guides for Unit 10 when you want a closer review of one topic.

browse guides

Practice questions

Use AP-style practice after you review the notes so you can check what you understand.

start practice

FRQ practice

Practice free-response reasoning and compare your answer with scoring guidance.

practice FRQs

Cram archive videos

Watch past review streams filtered to Unit 10 when you want a video walkthrough.

open videos

Official unit cheatsheet

Open the Fiveable one-page unit review, then explore visual cheatsheets for a quick refresher.

open unit cheatsheet

Score calculator

Estimate your broader AP score goal after you review the course and exam format.

open calculator

Unit 10 printables

Print the unit cheatsheets ($3) or unit exams ($5) for Unit 10. Yours to keep, no subscription needed.

get printables

Frequently Asked Questions

What's on the AP Physics 2 Unit 10 progress check (MCQ and FRQ)?

The AP Physics 2 Unit 10 progress check includes both MCQ and FRQ parts drawn from all 7 unit topics. The MCQ section tests concepts like electric charge, electric force, electric fields, and electric potential. The FRQ part asks you to apply those ideas quantitatively, often involving capacitors or conservation of electric energy. Practice with matched questions at AP Physics 2 Unit 10.

How do I practice AP Physics 2 Unit 10 FRQs?

AP Physics 2 Unit 10 FRQs most often pull from electric potential, electric fields, and capacitors. Questions typically ask you to derive or calculate quantities, draw or interpret field diagrams, and explain energy relationships using conservation of electric energy. To practice, work through problems that require you to connect multiple topics, like linking electric potential energy to capacitor charge storage, then check your reasoning step by step. Find practice FRQs at AP Physics 2 Unit 10.

Where can I find AP Physics 2 Unit 10 practice questions?

For AP Physics 2 Unit 10 practice questions, including multiple-choice and practice test sets, head to AP Physics 2 Unit 10. You'll find MCQs covering electric charge, electric force, electric fields, electric potential, and capacitors, plus full practice test questions organized by topic so you can target weak spots.

How should I study AP Physics 2 Unit 10?

Start with electric charge and electric force so Newton's laws feel familiar in an electrostatics context, then build toward electric potential and capacitors. Sketch field diagrams for every scenario you encounter. Practice moving between force, field, potential energy, and electric potential, since AP Physics 2 Unit 10 FRQs often require all four in one problem. After each topic, do a short set of MCQs to catch gaps early, then revisit conservation of electric energy last since it ties everything together. Organize your review at AP Physics 2 Unit 10.

Ready to review Unit 10?Start with the notes, check the topic cards, and use the practice or resource links when they are available for this course.

start unit practice review topics

Unit 9Back

NextUnit 11Unit 11 – Electric Circuits