Lesson Plan

• Describe the relationship between photon frequency, work function, and the maximum kinetic energy of emitted electrons.
• Explain why the maximum kinetic energy is independent of light intensity.
• Analyse how photoelectric current varies with light intensity and relate it to photon flux.
• Apply Einstein’s photoelectric equation to solve quantitative problems.

• Projector and screen
• Whiteboard and markers
• Printed worksheet with practice problems
• Monochromatic light source or laser pointer
• Photoelectric effect simulation (e.g., PhET)
• Calculators

Begin with a quick demonstration of a laser shining on a metal surface to spark curiosity about why light can eject electrons. Recall students’ prior knowledge of energy quantisation and the equation E = hν. State that by the end of the lesson they will be able to explain the distinct roles of frequency and intensity in the photoelectric effect.

1. Do‑Now (5′): Short quiz on photon energy and work function.
2. Concept Review (10′): Teacher explains Einstein’s photoelectric equation and the threshold frequency.
3. Interactive Simulation (15′): Students explore how changing frequency vs. intensity affects K_max and current, recording observations.
4. Guided Practice (10′): Work through a sample problem calculating K_max for different frequencies while keeping intensity constant.
5. Think‑Pair‑Share (5′): Discuss why increasing intensity changes current but not K_max.
6. Formative Check (5′): Exit ticket – one sentence answer to the lesson’s central question.

Summarise that photon frequency determines the energy each electron can receive, while intensity controls how many photons (and thus electrons) arrive per second. Collect exit tickets to gauge understanding and assign a worksheet for homework that reinforces calculations of K_max and photoelectric current.