Parent plan · Week 21 · Modern Physics — connect, calculate and revise — Physics & Environmental Science

Units to teach or revisit

Chapter 7 · Modern Physics

Assigned readings

The right model depends on the evidence and the event

Develop this chapter question: Which observations require models beyond everyday mechanics?

This week’s goals

Explain models, objects, arrows and axes before substituting values.
Conserve the relevant charge, momentum, matter and energy account.
Apply independently, state limits and revise from evidence.

Read The right model depends on the evidence and the event at chapter launch and revisit it alongside this week’s linked units, figures and investigation.

Five flexible sessions, normally 50–60 minutes. Two core unit sessions are scheduled, with a third for selected demanding topics. Sample week uses a complete 90-minute paper plus about 30 minutes of corrections within two ordinary-hour equivalents.

Session 1 · Extended calculation and transfer — Relativity, Light Speed & Model Limits

Use the linked chapter reading, unit explanations, figures and notebook.

Your task

Reconstruct a worked method without looking at its answer. Then solve this changed case, show intermediate steps and units, explain a limit and compare a second method where appropriate: A process has proper duration 3.0 μs and moves at 0.80c relative to a lab. Find γ and lab duration; a rest 10 m object moving parallel at that speed has what lab length?

Prepare the assigned explanation and identify the question.
Trace a model or graph, labeling its quantities and units.
Attempt the assigned reasoning and calculation before opening guidance.
Compare with criteria and retain an explained correction.

Hint and response guidance

Name the objects, quantities, boundary and assumptions before choosing a relationship. Use the matching figure to check each step.

γ=1/√0.36=5/3. Lab duration=5.0 μs; length=10/(5/3)=6.0 m, with simultaneous endpoints in the lab.

Use the supplied evidence and correct quantity/units.
Explain the relevant mechanism or relationship.
Show intermediate working or a labeled model.
State an assumption, limitation or useful next test.

Session 2 · Mass–Energy, Nuclear Reactions & Radiation Evidence — build the model

Use the linked chapter reading, unit explanations, figures and notebook.

Your task

Read the chapter background and unit language. Draw a first model, study the core explanation and Parts 1–2, trace each figure and attempt the visual questions/checks. Complete a first worked case with its answer covered.

Prepare the assigned explanation and identify the question.
Trace a model or graph, labeling its quantities and units.
Attempt the assigned reasoning and calculation before opening guidance.
Compare with criteria and retain an explained correction.

Hint and response guidance

Name the objects, quantities, boundary and assumptions before choosing a relationship. Use the matching figure to check each step.

A counts nucleons rather than exact rest mass. Different binding energies change the complete rest-mass total. Energy input is required for that channel under the stated account; the simple released-energy value is negative.

Use the supplied evidence and correct quantity/units.
Explain the relevant mechanism or relationship.
Show intermediate working or a labeled model.
State an assumption, limitation or useful next test.

Session 3 · Mass–Energy, Nuclear Reactions & Radiation Evidence — apply and explain

Use the linked chapter reading, unit explanations, figures and notebook.

Your task

Study Parts 3–4 and selected source-model prompts, then attempt the whole-unit application, illustrated practice and changed independent case. Explain a correction, revise the opening model and complete the exit check.

Prepare the assigned explanation and identify the question.
Trace a model or graph, labeling its quantities and units.
Attempt the assigned reasoning and calculation before opening guidance.
Compare with criteria and retain an explained correction.

Hint and response guidance

Name the objects, quantities, boundary and assumptions before choosing a relationship. Use the matching figure to check each step.

Energy≈0.0015×931.5=1.397 MeV/event. Dose also needs energy deposited, exposed mass, radiation characteristics and geometry; count rate includes detector efficiency/background and is not dose.

Use the supplied evidence and correct quantity/units.
Explain the relevant mechanism or relationship.
Show intermediate working or a labeled model.
State an assumption, limitation or useful next test.

Session 4 · Extended calculation and transfer — Mass–Energy, Nuclear Reactions & Radiation Evidence

Use the linked chapter reading, unit explanations, figures and notebook.

Your task

Reconstruct a worked method without looking at its answer. Then solve this changed case, show intermediate steps and units, explain a limit and compare a second method where appropriate: A supplied reaction releases 0.0015 u of rest-mass equivalent per event. Estimate energy in MeV, then explain why a detector count rate cannot directly give absorbed dose.

Prepare the assigned explanation and identify the question.
Trace a model or graph, labeling its quantities and units.
Attempt the assigned reasoning and calculation before opening guidance.
Compare with criteria and retain an explained correction.

Hint and response guidance

Name the objects, quantities, boundary and assumptions before choosing a relationship. Use the matching figure to check each step.

Energy≈0.0015×931.5=1.397 MeV/event. Dose also needs energy deposited, exposed mass, radiation characteristics and geometry; count rate includes detector efficiency/background and is not dose.

Use the supplied evidence and correct quantity/units.
Explain the relevant mechanism or relationship.
Show intermediate working or a labeled model.
State an assumption, limitation or useful next test.

Session 5 · Photoelectric Model from Data — plan and examine records

Use the linked chapter reading, unit explanations, figures and notebook.

Your task

Read the full investigation. Define question, boundary, variables, units and route. Use a suitable supervised method or the complete supplied-data route, preserving all records and a first model.

Prepare the assigned explanation and identify the question.
Trace a model or graph, labeling its quantities and units.
Attempt the assigned reasoning and calculation before opening guidance.
Compare with criteria and retain an explained correction.

Hint and response guidance

Name the objects, quantities, boundary and assumptions before choosing a relationship. Use the matching figure to check each step.

The work function is 2 eV. Above threshold Kmax=Ephoton−2 eV; a 1.5 eV photon lacks sufficient energy. Higher intensity at 3 eV gives more electrons but the same maximum energy. Multiphoton regimes are outside this model. Preserve the original observations, intermediate working and a labeled mechanism. Report the relevant boundary and model assumptions, discuss an alternative explanation, and identify the next useful measurement; do not replace unexpected data with the illustrative record.

Use the supplied evidence and correct quantity/units.
Explain the relevant mechanism or relationship.
Show intermediate working or a labeled model.
State an assumption, limitation or useful next test.

Submit this week

Labeled first/revised models and intermediate calculations.
Assigned practice and assessed attempts with explained corrections.
Investigation record/report when assigned, identifying supplied versus collected data.

Parent / teacher weekly conference

Use actual written work to adjust support. Do not count a copied solution as independent mastery. Extend or redistribute time where needed; home-study records do not certify supervised or mandated laboratory requirements.

Can each relevant symbol and unit be explained?
Does the calculation conserve the appropriate quantities?
Can the learner solve a changed case and explain an assumption?

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