AP Physics 2 Study Guide

The course picks up where Physics 1 leaves off and turns toward the electromagnetic and thermal world. You begin with thermodynamics — gas laws, the kinetic theory of temperature, and how energy moves as heat and work — then spend the bulk of the year on electricity and magnetism: the electric force between charges, the fields and potentials they create, the circuits built from them, and the deep link between moving charge and magnetism.

The final stretch covers optics (how light reflects, refracts, and interferes) and modern physics (photons, atomic energy levels, and the early quantum and nuclear ideas). The unifying habit across all of it is field thinking: instead of tracking pushes and pulls, you describe the invisible field a source sets up and ask what it does to anything placed inside it.

The six units are weighted fairly evenly on the multiple-choice section, but the spread still matters when you budget study time:

• Thermodynamics — ~18%
• Electric Circuits — ~18%
• Modern Physics — ~18%
• Electric Force, Field, and Potential — ~16%
• Geometric and Physical Optics — ~16%
• Magnetism and Electromagnetic Induction — ~14%

The takeaway: there is no single dominant unit, so neglecting any one of them quietly forfeits a real slice of the exam. Electricity in its various forms — fields, potential, and circuits — together makes up the largest theme, and it underpins both magnetism and modern physics, so build that foundation first.

Physics 2 is a conceptual reasoning exam built on a smaller set of equations than you might expect. A routine that works:

1. Draw the field or the ray. For E&M, sketch the field lines and equipotentials; for optics, draw the ray diagram. The picture decides the sign and direction before any number does.
2. Track energy across domains. Thermodynamics, circuits, and photons all come back to energy conservation. Practice writing where energy enters, leaves, and is stored.
3. Work in mixed sets. Studying one unit at a time hides the real skill, which is recognizing which model a scenario calls for. Mixed practice forces that choice.
4. Review with full solutions. The free-response section asks you to justify claims and design or critique experiments, so reading why an answer works — and why a tempting wrong one fails — pays off more than rushing to the next problem.

• Confusing electric field with electric potential — one is a vector that points, the other a scalar that adds, and mixing them wrecks both the math and the reasoning.
• Sign and direction errors with charge and current, especially forgetting that conventional current and electron flow point opposite ways.
• Misreading circuits by treating series and parallel branches interchangeably instead of tracing the actual paths for current and voltage.
• Forgetting that real images and virtual images behave differently, and sloppy sign conventions in the thin-lens and mirror equations.
• Vague free-response justifications. "The charge moves" earns little; "the field points away from the positive plate, so the positive charge accelerates toward the negative plate" earns the point.

Every unit below has a focused practice set with full written explanations and a rationale for every wrong choice, plus a worked-solutions page you can read straight through. Start with a unit you're shaky on, then take a mixed set across the whole subject to pressure-test your model selection before exam day. It's free and needs no account.