--- title: "Unit 15 – Modern Physics - AP Physics 2" description: "Review Unit 15 – Modern Physics for AP Physics 2 with Fiveable study guides and practice resources." canonical: "https://fiveable.me/ap-physics-2-revised/unit-15" type: "unit" subject: "AP Physics 2" unit: "Unit 15 – Modern Physics" --- # Unit 15 – Modern Physics - AP Physics 2 ## Overview Unit 15 – Modern Physics ## Study Guides - [15.1 Quantum Theory and Wave-Particle Duality](/ap-physics-2-revised/unit-15/1-quantum-theory-and-wave-particle-duality/study-guide/LU54fgTuvW1xw63V) - [15.2 The Bohr Model of Atomic Structure](/ap-physics-2-revised/unit-15/2-the-bohr-model-of-atomic-structure/study-guide/gzEFr1ron8hpACPx) - [15.3 Emission and Absorption Spectra](/ap-physics-2-revised/unit-15/3-emission-and-absorption-spectra/study-guide/QvJsunuWugAm3bOk) - [15.4 Blackbody Radiation](/ap-physics-2-revised/unit-15/4-blackbody-radiation/study-guide/jcWRJUVghpDEK71c) - [15.5 The Photoelectric Effect](/ap-physics-2-revised/unit-15/5-the-photoelectric-effect/study-guide/OLYoFyn8nutvrlZD) - [15.6 Compton Scattering](/ap-physics-2-revised/unit-15/6-compton-scattering/study-guide/OoE2k26dtiHSsZEf) - [15.7 Fission, Fusion, and Nuclear Decay](/ap-physics-2-revised/unit-15/7-fission-fusion-and-nuclear-decay/study-guide/nVULWHgdGjkiGhbI) - [15.8 Types of Radioactive Decay](/ap-physics-2-revised/unit-15/8-types-of-radioactive-decay/study-guide/yQriAHMZEcNvi6kE) ## FAQs ### What topics are covered in AP Physics 2 Unit 15? AP Physics 2 Unit 15 covers 8 topics in Modern Physics: Quantum Theory and Wave-Particle Duality, the Bohr Model of Atomic Structure, Emission and Absorption Spectra, Blackbody Radiation, the Photoelectric Effect, Compton Scattering, Fission, Fusion, and Nuclear Decay, and Types of Radioactive Decay. Together these topics explain how quantum theory replaced classical physics at the atomic and subatomic scale. See all 8 topics at [/ap-physics-2-revised/unit-15](/ap-physics-2-revised/unit-15). ### How much of the AP Physics 2 exam is Unit 15? Unit 15: Modern Physics makes up 12-15% of the AP Physics 2 exam, making it one of the more heavily weighted units. It covers quantum theory, the photoelectric effect, atomic structure, nuclear decay, fission, and fusion. Expect several multiple-choice questions and potential FRQ components drawn from these topics on exam day. ### What's on the AP Physics 2 Unit 15 progress check (MCQ and FRQ)? The AP Physics 2 Unit 15 progress check includes both MCQ and FRQ parts drawn from all 8 Modern Physics topics. The MCQ section tests conceptual understanding of the photoelectric effect, Compton scattering, blackbody radiation, atomic structure, and nuclear decay. The FRQ part asks you to apply quantum theory reasoning, interpret spectra, or work through nuclear processes quantitatively. Practice with matched questions at [/ap-physics-2-revised/unit-15](/ap-physics-2-revised/unit-15). ### How do I practice AP Physics 2 Unit 15 FRQs? The best way to practice AP Physics 2 Unit 15 FRQs is to focus on the topics that generate the most free-response questions: the photoelectric effect, emission and absorption spectra, and nuclear decay processes. FRQs in this unit typically ask you to explain phenomena using quantum theory, calculate photon energy or stopping voltage, or analyze nuclear equations. Practice by writing out full explanations, not just plugging numbers, since College Board awards points for reasoning. Find Unit 15 FRQ practice at [/ap-physics-2-revised/unit-15](/ap-physics-2-revised/unit-15). ### Where can I find AP Physics 2 Unit 15 practice questions? For AP Physics 2 Unit 15 practice questions, including multiple-choice and practice test sets, head to [/ap-physics-2-revised/unit-15](/ap-physics-2-revised/unit-15). There you'll find MCQ practice covering the photoelectric effect, Bohr model, Compton scattering, blackbody radiation, and nuclear decay, plus FRQ-style problems. Mixing MCQ and FRQ practice is the most effective way to prepare for the 12-15% of exam questions this unit represents. ### How should I study AP Physics 2 Unit 15? Start with the photoelectric effect and quantum theory since those concepts anchor everything else in Unit 15. Once you understand wave-particle duality and discrete energy levels, the Bohr model of atomic structure and emission spectra will click into place. From there, work through Compton scattering and blackbody radiation, then finish with fission, fusion, and radioactive decay. A few concrete steps that help: draw energy-level diagrams for the Bohr model, practice writing and balancing nuclear equations for decay types, and do timed MCQ sets to reinforce the conceptual reasoning College Board tests. Unit 15 is 12-15% of the exam, so it's worth steady, spaced review rather than a last-minute cram. Find study resources at [/ap-physics-2-revised/unit-15](/ap-physics-2-revised/unit-15). ## Structured Data ```json {"@context":"https://schema.org","@type":"FAQPage","inLanguage":"en","mainEntity":[{"@type":"Question","@id":"https://fiveable.me/ap-physics-2-revised/unit-15#what-topics-are-covered-in-ap-physics-2-unit-15","name":"What topics are covered in AP Physics 2 Unit 15?","acceptedAnswer":{"@type":"Answer","text":"AP Physics 2 Unit 15 covers 8 topics in Modern Physics: Quantum Theory and Wave-Particle Duality, the Bohr Model of Atomic Structure, Emission and Absorption Spectra, Blackbody Radiation, the Photoelectric Effect, Compton Scattering, Fission, Fusion, and Nuclear Decay, and Types of Radioactive Decay. Together these topics explain how quantum theory replaced classical physics at the atomic and subatomic scale. 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The MCQ section tests conceptual understanding of the photoelectric effect, Compton scattering, blackbody radiation, atomic structure, and nuclear decay. The FRQ part asks you to apply quantum theory reasoning, interpret spectra, or work through nuclear processes quantitatively. Practice with matched questions at /ap-physics-2-revised/unit-15."}},{"@type":"Question","@id":"https://fiveable.me/ap-physics-2-revised/unit-15#how-do-i-practice-ap-physics-2-unit-15-frqs","name":"How do I practice AP Physics 2 Unit 15 FRQs?","acceptedAnswer":{"@type":"Answer","text":"The best way to practice AP Physics 2 Unit 15 FRQs is to focus on the topics that generate the most free-response questions: the photoelectric effect, emission and absorption spectra, and nuclear decay processes. FRQs in this unit typically ask you to explain phenomena using quantum theory, calculate photon energy or stopping voltage, or analyze nuclear equations. Practice by writing out full explanations, not just plugging numbers, since College Board awards points for reasoning. Find Unit 15 FRQ practice at /ap-physics-2-revised/unit-15."}},{"@type":"Question","@id":"https://fiveable.me/ap-physics-2-revised/unit-15#where-can-i-find-ap-physics-2-unit-15-practice-questions","name":"Where can I find AP Physics 2 Unit 15 practice questions?","acceptedAnswer":{"@type":"Answer","text":"For AP Physics 2 Unit 15 practice questions, including multiple-choice and practice test sets, head to /ap-physics-2-revised/unit-15. There you'll find MCQ practice covering the photoelectric effect, Bohr model, Compton scattering, blackbody radiation, and nuclear decay, plus FRQ-style problems. Mixing MCQ and FRQ practice is the most effective way to prepare for the 12-15% of exam questions this unit represents."}},{"@type":"Question","@id":"https://fiveable.me/ap-physics-2-revised/unit-15#how-should-i-study-ap-physics-2-unit-15","name":"How should I study AP Physics 2 Unit 15?","acceptedAnswer":{"@type":"Answer","text":"Start with the photoelectric effect and quantum theory since those concepts anchor everything else in Unit 15. Once you understand wave-particle duality and discrete energy levels, the Bohr model of atomic structure and emission spectra will click into place. From there, work through Compton scattering and blackbody radiation, then finish with fission, fusion, and radioactive decay. A few concrete steps that help: draw energy-level diagrams for the Bohr model, practice writing and balancing nuclear equations for decay types, and do timed MCQ sets to reinforce the conceptual reasoning College Board tests. Unit 15 is 12-15% of the exam, so it's worth steady, spaced review rather than a last-minute cram. Find study resources at /ap-physics-2-revised/unit-15."}}]} ```