AP Physics 2 Units 2027
AP Physics 2 has 7 units, numbered 9 through 15, containing 46 topic lessons. Units 9–11 each carry a 15–18% multiple-choice weighting range; Units 12–15 each carry 12–15%. Use this page to compare units, understand how the physics connects and decide where your review time should go.
What are the 7 AP Physics 2 units?
The seven units are Thermodynamics; Electric Force, Field, and Potential; Electric Circuits; Magnetism and Electromagnetism; Geometric Optics; Waves, Sound, and Physical Optics; and Modern Physics. They form one connected second-course sequence rather than seven isolated chapters.
Why does AP Physics 2 start with Unit 9?
The numbering continues from the first-course sequence: Units 1–8 cover the first-course mechanics and fluids foundation, so this second-course sequence begins at Unit 9 and continues through Unit 15. Starting at 9 does not mean that seven Physics 2 units are missing.
All 7 units at a glance
Start with the unit whose models or representations are weakest. Weighting is useful for planning, but it should not replace evidence from your own mistakes.
Thermodynamics
State variables, microscopic models, P–V diagrams, heat/work/internal energy and entropy.
Electric Force, Field, and Potential
Charge interactions, vector fields, scalar potential, capacitors and electric-energy reasoning.
Electric Circuits
Current, potential difference, resistance, power, network conservation and RC transients.
Magnetism and Electromagnetism
Magnetic-field direction, force on charges/currents, magnetic flux and electromagnetic induction.
Geometric Optics
Ray diagrams, reflection/refraction, image formation, focal length and optical sign conventions.
Waves, Sound, and Physical Optics
Wave propagation, phase, sound, polarization, interference, diffraction and physical optics.
Modern Physics
Photons, matter waves, atomic energy levels, spectra, radiation and nuclear processes.
Topic count, weighting and the skill that usually matters most
The examples show the kind of reasoning each unit demands; they are not a complete list of what can be tested.
| Unit | Topics | MCQ weighting | Approx. pacing | Representation to master | Real study example |
|---|---|---|---|---|---|
| 9 · Thermodynamics | 6 | 15–18% | 10–16 class periods | P–V diagrams; heating/cooling graphs; energy-flow diagrams | Read a P–V path and decide the signs of work, heat transfer and internal-energy change. |
| 10 · Electric Force, Field, and Potential | 7 | 15–18% | 14–21 class periods | field vectors; field-line/equipotential maps; energy-vs-position reasoning | Compare electric field and potential at several locations around a charge distribution. |
| 11 · Electric Circuits | 8 | 15–18% | 12–20 class periods | circuit schematics; I–V graphs; exponential RC curves | Predict how removing one branch changes current and bulb power elsewhere in a network. |
| 12 · Magnetism and Electromagnetism | 4 | 12–15% | 10–13 class periods | magnetic-field/force vectors; flux diagrams; emf-time graphs | Use a changing magnetic flux to predict induced-current direction and induced emf. |
| 13 · Geometric Optics | 4 | 12–15% | 8–12 class periods | ray diagrams; image geometry; refraction sketches | Construct principal rays to locate an image and determine whether it is real or virtual. |
| 14 · Waves, Sound, and Physical Optics | 9 | 12–15% | 14–23 class periods | wave snapshots; displacement-time graphs; interference/diffraction patterns | Predict how changing wavelength or slit spacing changes an interference or diffraction pattern. |
| 15 · Modern Physics | 8 | 12–15% | 14–22 class periods | energy-level diagrams; spectra; photoelectric and decay graphs | Use photon energy and an energy-level diagram to predict emitted or absorbed wavelengths. |
| Total | 46 | All seven units are represented by dedicated hubs and topic lessons. | |||
Fields, energy and waves keep reappearing
The fastest improvement comes from recognizing ideas that migrate from one unit to another instead of relearning each chapter from zero.
On a small screen, swipe the map horizontally to keep every label readable.
Energy thread
Thermal internal energy → electric potential energy → circuit power → photon and nuclear energy. Track what the system stores, transfers and dissipates.
Field thread
Electric fields establish the language used again in magnetic fields and electromagnetic induction. Direction, source and interaction stay central.
Wave thread
Periodic waves, phase, interference and diffraction lead naturally into electromagnetic waves and the wave-particle questions of modern physics.
Representation thread
Diagrams, graphs, equations and verbal claims must describe the same physical model in every unit.
What is inside each unit
Use these compact lists to locate a topic quickly. The syllabus and curriculum page owns the complete course-planning view.
Unit 9 · Thermodynamics15–18%
Unit 10 · Electric Force, Field, and Potential15–18%
Unit 11 · Electric Circuits15–18%
Unit 12 · Magnetism and Electromagnetism12–15%
Unit 13 · Geometric Optics12–15%
Unit 14 · Waves, Sound, and Physical Optics12–15%
Which unit should you review first?
Do not rank units by reputation alone. Rank them by the combination of weighting, weakness and repeated error type.
Measure weakness
Use topic MCQs and FRQs to identify where your model selection or representation breaks down.
Consider weighting
Units 9–11 have the largest individual weighting ranges, but all seven units matter.
Repair the skill
Fix graph interpretation, vector direction, experiment design or written justification—not only the formula.
Retest mixed
Return to mixed questions so the same concept is recognized in a new context.
Students often find Unit 10 difficult because field is a vector while potential is a scalar, Unit 11 because network relationships interact, Unit 14 because phase and path difference are easy to confuse, and Unit 15 because several models of light and matter must coexist. Use your own error log to decide what is actually hardest for you.
AP Physics 2 units: fast answers
Use these short answers for the questions students most often need before choosing what to study.
How many units are in AP Physics 2?
There are 7 units, numbered 9 through 15, containing 46 topics in this learning system.
Why are there no Units 1–8 on this page?
The numbering is continuous across the two-course sequence. The first course uses Units 1–8, so Physics 2 begins with Unit 9.
Which units have the largest weighting ranges?
Units 9, 10 and 11 each carry a 15–18% multiple-choice weighting range. Units 12–15 each carry 12–15%.
Which AP Physics 2 unit is hardest?
There is no universal hardest unit. Difficulty depends on whether your weaker skill is field reasoning, circuit networks, wave phase/interference, modern-physics models, graphs or written justification.
Should I study the units in numerical order?
For a first pass, numerical order is useful because ideas build across energy, fields, circuits and waves. For review, prioritize the units and skills your practice results show are weakest.
Where is the complete AP Physics 2 curriculum?
The syllabus and curriculum page lists all 46 topics plus prerequisites, mathematics, labs, pacing and an assessment workflow.