AP Physics C E&M Full Mock Test 2 — Electrostatics and Capacitor Geometry Focus
AP Physics C E&M Full Mock 2 emphasises electrostatics: Gauss's law derivations, electric potential integrals, and capacitor geometry derivations in FRQ format.
About Full Mock 2
Full Mock 2 for AP Physics C: Electricity & Magnetism concentrates the most challenging questions on electrostatics — Units 8, 9, and 10 — while maintaining coverage of all six units in the full 35 MCQ + 3 FRQ format. Students who found Gauss's law derivations, potential integrations, or capacitance geometry problems to be sources of difficulty in Mock 1 will find Mock 2 provides intensive targeted practice in these areas.
Electrostatics Emphasis: Key Areas Tested
Gauss's Law Derivations (Unit 8)
Mock 2 includes multiple FRQ and MCQ items requiring full Gauss's law setups for non-trivial geometries. Expect problems involving:
- Non-uniform volume charge distributions where Q_enc requires integration: Q_enc = ∫ρ(r) dV over the enclosed volume
- Conducting shells with cavities — requiring multiple Gaussian surfaces at different radii
- Comparison of E(r) for conducting versus insulating spheres with the same total charge
Electric Potential Integrations (Unit 9)
Potential calculations in Mock 2 go beyond on-axis symmetry. Problems include computing V at points off the symmetry axis using scalar superposition, evaluating ΔV by integrating E along a specified path in a non-uniform field, and verifying continuity of V at boundaries between regions with different charge distributions.
Capacitor Geometry Derivations (Unit 10)
The FRQs in Mock 2 include full capacitance derivations as subparts — beginning from Gauss's law, proceeding through the E field, integrating for V, and computing C = Q/V. Both cylindrical and spherical capacitor geometries appear. Energy storage and the effect of dielectric insertion are tested as follow-on parts of these derivations.
MCQ and FRQ Distribution
In Mock 2, approximately 55% of MCQ items draw primarily from Units 8–10, while the remaining 45% maintain coverage of Units 11–13 at standard difficulty. The three FRQs are weighted toward electrostatics: two of the three have electrostatics as the dominant topic, with one focusing on circuit analysis and induction for balance.
Who Should Prioritise Mock 2
Mock 2 is particularly valuable for students who:
- Scored well on Units 11–13 in Mock 1 but lost points on Units 8–10 derivations
- Need additional practice with Gaussian surface arguments and the step-by-step capacitance derivation process
- Want to consolidate electrostatics before building confidence in magnetism and induction
Key Takeaway from Mock 2
By the end of Mock 2, students should be able to derive the capacitance of any geometry presented from first principles using Gauss's law — not by recalling a formula. This derivation competency is the foundation AP-style FRQ graders look for, and it directly transfers to Unit 12 (where Ampere's law derivations follow an analogous structure) and Unit 13 (where flux integrals build on the same surface integral framework).