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University Physics III

University Physics III · Quantum Physics · 9.03

Photon momentum and Compton scattering

Photon momentum h over λ, relativistic two-body scattering kinematics, the Compton shift as h over m c times one minus cosine θ with h over m c equal to 2.43 pm for an electron, and radiation pressure; the free-electron approximation fails for tightly bound inner-shell electrons, which return the unshifted line.

Course-map guide · not a complete lesson or simulation

Scope & orientation

What this subsection covers

Photon momentum h over λ, relativistic two-body scattering kinematics, the Compton shift as h over m c times one minus cosine θ with h over m c equal to 2.43 pm for an electron, and radiation pressure; the free-electron approximation fails for tightly bound inner-shell electrons, which ret…

A strong response uses wavefunction and probability-density plots and states where the model stops being reliable.

Reasoning checklist

Evidence, assumptions and limits

01

Assumptions to state

State the system, observable, approximation, and conditions held fixed before using a model.

02

Evidence to collect

Does stopping potential vary linearly with frequency, and what value of h and work function does the fit support?

Read the complete note

Does stopping potential vary linearly with frequency, and what value of h and work function does the fit support? Useful evidence includes stopping-potential data at several source frequencies, a linear fit with slope h/e and intercept minus φ/e, residuals, propagated uncertainty, and a stated range of validity.

03

Limits to state

This GioPhysics course map is an adaptable learning sequence, not academic credit, accreditation, or a universal university syllabus.

Read the complete note

This GioPhysics course map is an adaptable learning sequence, not academic credit, accreditation, or a universal university syllabus. Third-semester content is the least standardised of the introductory sequence: departments place oscillations, waves, optics, and thermal physics differently, and the modern-physics units here are a bounded survey rather than a complete course in relativity, quantum mechanics, atomic, nuclear, or particle physics. Follow your institution's published scope, notation, laboratory programme, and assessment rules. A result should be checked against units, signs, limiting cases, and the conditions under which its model was derived.

Diagram & examples

Work the claim before choosing an equation

Interactive concept map

Follow the model from claim to evidence.

01 · Physical claimPhoton momentum and Compton scattering

Photon momentum h over λ, relativistic two-body scattering kinematics, the Compton shift as h over m c times one minus cosine θ with h over m c equal to 2.43 pm for an electron, and radiation pressure.

Read the complete note

Photon momentum h over λ, relativistic two-body scattering kinematics, the Compton shift as h over m c times one minus cosine θ with h over m c equal to 2.43 pm for an electron, and radiation pressure; the free-electron approximation fails for tightly bound inner-shell electrons, which return the unshifted line.

02 · RepresentationThe subsection's claim

Model, evidence, and boundary

03 · TestPrediction before measurement

Which response about Photon momentum and Compton scattering is most defensible?

04 · Evidence & boundaryDecide, then qualify

Does stopping potential vary linearly with frequency, and what value of h and work function does the fit support?

Read the complete note

Does stopping potential vary linearly with frequency, and what value of h and work function does the fit support? Useful evidence includes stopping-potential data at several source frequencies, a linear fit with slope h/e and intercept minus φ/e, residuals, propagated uncertainty, and a stated range of validity.

Interactive diagram for Photon momentum and Compton scattering: follow the physical claim through its representation, proposed test, evidence, and model boundary.

modelModel, evidence, and boundary turns the stated idea into a representation that can make a prediction.

Example questions

Try the reasoning before revealing the structure.

Diagram check

Which response about Photon momentum and Compton scattering is most defensible?

Quick check

Test the reasoning, not recall

Which response about Photon momentum and Compton scattering is most defensible?

Choose an answer to test the model.