# AP Physics C: Electricity and Magnetism exam guide > Calculus-based electricity and magnetism across the six units of the revised framework, from Gauss's law to induction. - Canonical page: https://www.arcadesacademy.com/exams/ap-physics-c-electricity-and-magnetism - Markdown source: https://www.arcadesacademy.com/exams/ap-physics-c-electricity-and-magnetism/llms.txt - Exam family: AP exams - Governing body: College Board - Official exam information: https://apstudents.collegeboard.org/courses/ap-physics-c-electricity-and-magnetism - Who takes it: High school students who have taken or are taking calculus and mechanics, typically those planning to study engineering or the physical sciences. - Follows the fall 2024 course and exam description, from 15 May 2025 - Guide structure last checked against official sources: August 30, 2026 ## Overview AP Physics C: Electricity and Magnetism is a calculus-based course covering electrostatics, conductors and capacitors, circuits, magnetic fields, and electromagnetic induction. Vector calculus at the level of Gauss's law and Ampere's law is used throughout, and integration over charge and current distributions is a routine skill rather than an occasional one. In the revised framework effective fall 2024, the course is organized into six units numbered 8 through 13, continuing the numbering from AP Physics C: Mechanics, which College Board treats as a functional prerequisite. The exam was lengthened to three hours with a longer multiple-choice section and four free-response questions. Arcade Academy is an independent study workspace. Because the framework and exam were revised recently, treat the official Course and Exam Description and exam page as authoritative for unit organization, published weightings, and current timing, and use the unit pages below to organize problem practice. ## Exam format - **Total time:** 3 hours - **Section I:** 42 multiple-choice questions in 1 hour 25 minutes, 50% of the exam score - **Section II:** 4 free-response questions, 50% of the exam score - **Format update:** The multiple-choice count and per-section timing changed beginning with the May 2027 exam; confirm the current numbers on the official exam page - **Delivery:** Hybrid digital: multiple-choice questions are answered and free-response prompts are read in College Board's Bluebook app, and free-response answers are handwritten in a paper booklet - **Calculator:** Permitted on the exam; an equations and reference information sheet is provided - **Prerequisites:** Calculus is used throughout, and College Board treats AP Physics C: Mechanics as a functional prerequisite - **Score scale:** 1 to 5 ## Scoring The multiple-choice and free-response sections each contribute half of a composite score, which College Board converts to the reported 1 to 5 scale using cut points set for that year's exam. This exam is scored separately from AP Physics C: Mechanics, and colleges set their own credit and placement policies for each. ## Units AP Physics C: Electricity and Magnetism is organized into 6 units. Each one below lists its published weighting where the governing body publishes one, the topics it covers, and study tips specific to it. ### 1. Unit 8: Electric Charges, Fields, and Gauss's Law - Position: 1 of 6 - Page: https://www.arcadesacademy.com/exams/ap-physics-c-electricity-and-magnetism/unit-8-electric-charges-fields-and-gausss-law Unit 8 builds electrostatics from charge through field, culminating in Gauss's law. The distinctive skill is computing the field of a continuous charge distribution, either by direct integration or by exploiting symmetry with a well-chosen Gaussian surface. Recognizing which method a given geometry calls for is itself a tested judgment. #### Topics - **Electric charge and charging processes** — Conservation and quantization of charge, and charging by friction, conduction, and induction. - **Coulomb's law and superposition** — Force between point charges and the vector sum of contributions from multiple charges. - **Electric fields** — Field as force per unit charge, field-line representations, and fields of standard configurations. - **Fields of continuous charge distributions** — Integrating over lines, rings, disks, and shells to find the resulting field. - **Electric flux** — Flux through a surface, its dependence on orientation, and evaluating it for symmetric geometries. - **Gauss's law** — Relating enclosed charge to flux, and using spherical, cylindrical, and planar symmetry to find fields quickly. #### Study tips - Practice choosing the Gaussian surface first and justify the choice from the symmetry of the distribution. - Work at least one field-by-integration problem for a ring and for a rod so the setup is familiar. - Check limiting cases (far away, on axis, at the center) to validate any field expression you derive. ### 2. Unit 9: Electric Potential - Position: 2 of 6 - Page: https://www.arcadesacademy.com/exams/ap-physics-c-electricity-and-magnetism/unit-9-electric-potential Unit 9 develops the energy view of electrostatics. Electric potential energy and potential are defined by integrating field along a path, and field is recovered by differentiating potential. Because potential is a scalar, it is often the faster route to a field for complicated distributions. #### Topics - **Electric potential energy** — Work done by the electric force, and the energy of assembling a configuration of charges. - **Electric potential** — Potential as energy per unit charge, and its computation for point charges and distributions. - **Potential from field and field from potential** — Integrating the field along a path to obtain potential, and differentiating potential to recover the field. - **Equipotential surfaces** — Reading equipotential maps, their perpendicular relationship to field lines, and the spacing that indicates field strength. - **Conservation of electric energy** — Tracking energy for charges moving in a field, and combining electric with mechanical energy. #### Study tips - Compute potential first for complicated distributions, then differentiate; it is usually far less algebra than a vector integral. - Practice sketching equipotentials alongside field lines for standard configurations. - Keep the sign of work and potential energy straight by naming the charge sign and the direction of motion explicitly. ### 3. Unit 10: Conductors and Capacitors - Position: 3 of 6 - Page: https://www.arcadesacademy.com/exams/ap-physics-c-electricity-and-magnetism/unit-10-conductors-and-capacitors Unit 10 covers the behavior of conductors in electrostatic equilibrium and the devices that exploit it. Charge resides on conductor surfaces, the interior field vanishes, and charge redistributes when conductors are connected. Capacitance, stored energy, and dielectrics complete the unit. #### Topics - **Electrostatics with conductors** — Why the field inside a conductor in equilibrium is zero and how surface charge arranges itself. - **Redistribution of charge between conductors** — What happens when two charged conductors are connected, and the role of potential in the final state. - **Capacitance** — Definition of capacitance and its calculation for parallel-plate, cylindrical, and spherical geometries. - **Energy stored in capacitors** — The several equivalent expressions for stored energy, and energy density in the field. - **Dielectrics** — How an inserted dielectric changes capacitance, field, and stored energy under fixed charge or fixed voltage. #### Study tips - Work dielectric problems twice: once with the battery connected and once disconnected, since the answers differ. - Derive parallel-plate capacitance from Gauss's law so the result is reconstructable. - Track which quantity is held constant in every capacitor problem before deciding what changes. ### 4. Unit 11: Electric Circuits - Position: 4 of 6 - Page: https://www.arcadesacademy.com/exams/ap-physics-c-electricity-and-magnetism/unit-11-electric-circuits Unit 11 covers steady-state and time-dependent direct-current circuits. Resistors in series and parallel and Kirchhoff's rules handle the steady case, while RC circuits introduce exponential charging and discharging with a characteristic time constant. Sketching and interpreting those exponential curves is a frequent exam task. #### Topics - **Current, resistivity, and resistance** — Current as charge flow rate, and how geometry and material set resistance. - **Series and parallel combinations** — Equivalent resistance and capacitance, and how current and potential difference distribute. - **Kirchhoff's rules** — Junction and loop rules as statements of charge and energy conservation, applied to multiloop circuits. - **Power and internal resistance** — Energy dissipation in resistors, terminal voltage, and the effect of a battery's internal resistance. - **RC circuits** — Exponential charging and discharging, the time constant, and the initial and final behavior of the circuit. #### Study tips - Learn the two limiting behaviors of a capacitor in a circuit: uncharged behaves like a wire, fully charged behaves like a break. - Sketch charge and current versus time for both charging and discharging and label the time constant on each. - Redraw multiloop circuits before applying Kirchhoff's rules, and assign loop directions before writing equations. ### 5. Unit 12: Magnetic Fields - Position: 5 of 6 - Page: https://www.arcadesacademy.com/exams/ap-physics-c-electricity-and-magnetism/unit-12-magnetic-fields Unit 12 covers magnetic force and the fields that produce it. Forces on moving charges and current-carrying wires lead into the Biot-Savart law for arbitrary current elements and Ampere's law for symmetric configurations. As with Gauss's law, recognizing when symmetry makes Ampere's law usable is the central judgment. #### Topics - **Magnetic force on moving charges** — The velocity-dependent force, circular and helical paths, and the velocity selector configuration. - **Magnetic force on current-carrying wires** — Force on a straight or curved wire in a field, and torque on a current loop. - **Biot-Savart law** — Field from a current element, and integrating it for straight segments, arcs, and loops. - **Ampere's law** — Using symmetry to find the field of long wires, solenoids, and toroids. - **Fields of standard current configurations** — Comparing the field patterns of a straight wire, a loop, and a solenoid. #### Study tips - Drill the right-hand rules in short daily sessions; three-dimensional orientation errors are the dominant loss here. - Practice choosing an Amperian loop and justifying the choice from the symmetry present. - Contrast Biot-Savart with Ampere's law explicitly: one always works but is slower, the other is fast only with symmetry. ### 6. Unit 13: Electromagnetic Induction - Position: 6 of 6 - Page: https://www.arcadesacademy.com/exams/ap-physics-c-electricity-and-magnetism/unit-13-electromagnetic-induction Unit 13 closes the course with changing fields. Magnetic flux, Faraday's law, and Lenz's reasoning connect a changing flux to an induced potential difference and current. Inductance, energy stored in an inductor, and LR and LC circuits extend the treatment to time-dependent circuits. #### Topics - **Magnetic flux** — Flux through a surface and the three ways it can change: field strength, area, or orientation. - **Faraday's law and Lenz's law** — Induced potential difference from the rate of flux change, and the direction that opposes the change. - **Motional emf and induced forces** — Emf from a conductor moving through a field, and the retarding force that results. - **Inductance** — Self-inductance, the energy stored in an inductor, and the field energy density. - **LR circuits** — Exponential current growth and decay with an inductor, and the circuit time constant. - **LC circuits** — Oscillation between capacitor and inductor energy, and the angular frequency of the oscillation. #### Study tips - Identify which flux factor is changing before applying Faraday's law; this single habit prevents most errors. - Practice stating the induced current direction in words using opposition to the change, then verify with a rule. - Compare RC and LR circuits side by side; the mathematics is parallel and learning them together halves the work. ## Study strategies - Build fluency with the two symmetry laws, Gauss's law and Ampere's law, since choosing the right surface or loop is what makes hard problems tractable. - Practice setting up integrals over continuous charge and current distributions, because recognizing the setup is worth more exam points than finishing the algebra. - Work RC, LR, and LC circuits together as one family, since their differential equations and exponential or oscillatory solutions mirror each other. - Rehearse the right-hand rules on a schedule; they decay quickly and cost very little to maintain. - Solve symbolically and check limiting cases, which both validates answers and matches how many exam questions are asked. - Use the official Course and Exam Description for unit organization and published weightings, since the framework was revised recently. ## Frequently asked questions ### How is the AP Physics C: Electricity and Magnetism Exam structured? The exam runs 3 hours and is split evenly between a multiple-choice section worth 50% of the score and a free-response section of 4 questions worth the other 50%. The multiple-choice count and section timing changed beginning with the May 2027 exam, so confirm current numbers on the official exam page. ### Do I need AP Physics C: Mechanics first? College Board treats mechanics as a functional prerequisite, and the revised framework numbers the Electricity and Magnetism units 8 through 13 to continue from it. The two are separate exams with separate scores, but the energy, force, and calculus habits from mechanics carry over directly. ### Which topics do students find most challenging? College Board does not rank difficulty. Students commonly report that field calculations for continuous distributions, the geometry of magnetic force problems, and induction direction questions demand the most practice. Let your own practice results set priorities. ### How is the exam scored? Both sections contribute equally to a composite score that is converted to the reported 1 to 5 scale using cut points set each year. Credit and placement decisions belong to individual colleges, and a college may grant credit for this exam without granting it for mechanics. ### When do students usually begin exam preparation? Because the course is problem-driven, the common approach is continuous problem practice through the year followed by cumulative timed practice starting roughly two months before the exam, rather than a late content review. ### Is Arcade Academy affiliated with College Board? No. AP® is a registered trademark of College Board, which was not involved in the production of, and does not endorse, this site. Arcade Academy is an independent educational resource. ## Related exam guides - [AP Physics C: Mechanics](https://www.arcadesacademy.com/exams/ap-physics-c-mechanics): Calculus-based mechanics across the seven units of the revised framework, from kinematics to oscillations. - [AP Physics 2: Algebra-Based](https://www.arcadesacademy.com/exams/ap-physics-2): Cover the seven units of the revised AP Physics 2 framework, thermodynamics through modern physics, with published weightings. - [AP Calculus BC](https://www.arcadesacademy.com/exams/ap-calculus-bc): All ten AP Calculus BC units with published exam weightings, including parametric and polar functions and infinite series. ## Independence and trademark notice AP® is a registered trademark of College Board, which was not involved in the production of, and does not endorse, this site. Arcade Academy is an independent educational resource. Confirm current exam format, dates, and policies with College Board directly. AP® is a registered trademark of College Board, which was not involved in the production of, and does not endorse, this site. Arcade Academy is an independent educational resource.