| Lesson Plan |
| Grade: Year 12 |
Date: 01/12/2025 |
| Subject: Physics |
| Lesson Topic: recall and use hf = Φ + 21mvmax2 |
Learning Objective/s:
- Describe the relationship between photon frequency, energy, and momentum.
- Apply the photoelectric equation hf = Φ + ½ mvmax² to calculate kinetic energy and electron speed.
- Calculate photon energy and momentum for given wavelengths using E = hf and p = h/λ.
- Interpret photon‑energy tables and relate them to real‑world applications such as solar cells.
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Materials Needed:
- Projector and screen
- Whiteboard and markers
- Printed worksheet with photon data table
- Calculator or computer with spreadsheet
- Laser pointer or LED for demonstration (optional)
- Student notebooks
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Introduction:
Begin with a quick demonstration of a laser pointer illuminating a metal surface, asking students what they observe. Review the concepts of energy and momentum of light and recall the equation E = hf. State that by the end of the lesson they will be able to use the photoelectric equation to predict electron speeds.
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Lesson Structure:
- Do‑now (5') – Students convert a given wavelength to frequency and energy.
- Mini‑lecture (10') – Derive photon momentum p = h/λ and introduce the photoelectric equation.
- Guided example (12') – Work through the 400 nm metal work‑function problem, prompting students to fill steps on the board.
- Group activity (15') – Teams calculate energy and momentum for different colours using the provided table and complete a worksheet.
- Concept check (5') – Quick clicker quiz on the meaning of Φ and vmax.
- Summary discussion (8') – Students explain why light intensity affects electron count but not vmax.
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Conclusion:
Recap the key links between frequency, photon energy, momentum and the photoelectric equation. Ask each student to write one exit‑ticket answer: the maximum kinetic energy for a photon of 500 nm. Assign homework to solve three additional photoelectric problems from the textbook.
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