AP Physics 2 FRQ Practice by Topic 2027
Every topic has four substantial free-response tasks: Mathematical Routines, Translation Between Representations, Experimental Design and Analysis, and Qualitative/Quantitative Translation. Select one topic, write the response before opening guidance, then use the evidence checklist or self-grader to find what your reasoning is missing.
What do the four AP Physics 2 FRQ practice modes test?
The four sets force you to calculate, translate representations, design/analyze experiments, and connect qualitative predictions to quantitative relationships. That prevents FRQ practice from becoming four copies of the same algebra problem.
One topic at a time keeps the page focused
Lesson pages link directly to the matching set; the base FRQ page remains a directory rather than rendering all 184 prompts at once.
Compton Scattering FRQ Set
Compton scattering is a photon–electron collision in which energy and two-dimensional momentum are conserved; the scattered photon generally leaves with lower energy, lower momentum and longer wavelength, with the wavelength shift set by scattering angle.
Use full quantitative and qualitative two-dimensional momentum conservation. Do not reduce a noncollinear photon–electron event to a one-dimensional scalar momentum equation.
Situation: A student analyzes this Compton Scattering situation: X-ray photons scattered by electrons show an angle-dependent wavelength increase that classical wave-only scattering cannot explain.
- State the governing model and define the system or physical quantities that matter.
- Starting from Δλ = (h/mec)(1 − cosθ), derive a symbolic expression for a requested target quantity before substituting numbers.
- Explain how the result changes when one relevant variable is multiplied by a factor while the other model conditions remain fixed.
- Give one units, sign/direction, limiting-case or order-of-magnitude check that could expose an incorrect result.
Open reasoning and scoring evidence
- The response must select Δλ = (h/mec)(1 − cosθ) only when Compton scattering of a photon from an approximately free electron.
- Symbols should be consistent with: Δλ=λf−λi wavelength increase (m); h Planck constant; me electron mass; c light speed; θ photon scattering angle.
- The proportional comparison must follow the functional dependence of the selected relationship rather than an unrelated equation.
- The final check must be physically interpretable, not just a calculator repeat.
Situation: Consider A momentum-vector diagram is required when the scattered photon and recoil electron leave in different directions; scalar momentum magnitudes alone are not enough. The same physics must be represented verbally, graphically and mathematically.
- Draw or describe a labeled physical representation showing the important objects, directions, boundaries or measured quantities.
- Sketch the graph or spatial representation that best displays the predicted behavior; label axes, signs and important features.
- Write a relationship consistent with the representation, using pγ = h/λ when its condition “incident or scattered photon momentum” is satisfied.
- Explain one explicit connection among the diagram/graph, the equation and the physical meaning of Compton scattering.
Open reasoning and scoring evidence
- The representation must encode the actual physical situation rather than act as decoration.
- Graph features such as slope, area, intercept, curvature, maxima/minima or direction must be linked to the relevant model.
- A valid equation must use variables/units consistently: pγ photon momentum (kg·m/s); h Planck constant; λ photon wavelength (m).
- Compton scattering means an interaction in which a photon scatters from an approximately free electron and transfers energy and momentum to it; the explanation should use that meaning to connect the representations.
Situation: Design an investigation for this target: Analyze measured scattered-photon wavelength versus angle; compare with the Compton-shift prediction and use vector momentum/energy conservation to test a selected event.
- State the independent variable, dependent variable and at least two quantities that must be controlled or measured.
- Describe a feasible apparatus/procedure that produces repeated measurements across a useful range of the independent variable.
- Choose a graph or linearization whose slope/intercept/shape tests a relationship such as Eγ = hc/λ and explain the expected trend.
- Explain how repeats, uncertainty and one plausible systematic effect influence the strength of the conclusion.
Open reasoning and scoring evidence
- The procedure must vary one intended cause while controlling plausible competing causes.
- Measurements must be sufficient to test a relationship rather than produce one isolated value.
- The graph choice must follow the expected functional dependence and connect a graph feature to a physical quantity.
- Uncertainty discussion must affect the evidence claim; simply saying “human error” is not enough.
Situation: Compare two valid Compton Scattering scenarios based on X-ray photons scattered by electrons show an angle-dependent wavelength increase that classical wave-only scattering cannot explain. In the second scenario, one relevant variable changes while the model remains valid.
- Predict whether the target physical quantity increases, decreases or remains unchanged before doing algebra.
- Justify the prediction using the physical meaning of scattering angle (the angle between the incident photon direction and the outgoing photon direction).
- Use Δλ = (h/mec)(1 − cosθ) or another appropriate relationship from this topic to determine a symbolic factor or ratio.
- State the model boundary that must remain satisfied: Use full quantitative and qualitative two-dimensional momentum conservation. Do not reduce a noncollinear photon–electron event to a one-dimensional scalar momentum equation.
Open reasoning and scoring evidence
- The qualitative prediction should appear before the quantitative calculation and should not depend on hindsight.
- The justification must name a physical cause/model, not simply restate that one variable became larger or smaller.
- The symbolic ratio must follow the correct functional dependence and preserve what is held fixed.
- A complete answer states the boundary/assumption so the comparison is not overgeneralized.
Use the FRQ Self-Grader to check evidence quality, then switch to a different topic or a full model exam. Do not improve the response merely by copying phrases from the scoring guide.
AP Physics 2 FRQ practice questions
How many FRQs are available per topic?
Four original multipart FRQs per topic, for 184 topic FRQs across all 46 topics.
Why are there four different FRQ modes?
They deliberately exercise different physics actions: mathematical reasoning, representation translation, experimental/data reasoning and qualitative-to-quantitative reasoning.
Should I open the reasoning guide while writing?
No. Finish a defensible response first. Open the guide only after you have committed to your model, representation and evidence.
Are drafts uploaded or stored on a server?
No server submission is used. The optional response workspace stores drafts only in your own browser when local storage is available.
How should I score my response?
Use the task-specific reasoning guide plus the separate FRQ Self-Grader. Look for explicit evidence, not just a correct final number.
When should I move to full practice exams?
After you can produce complete topic-level responses without relying on the guide. Full exams test whether you can identify the model without a topic heading.