Lesson Plan

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Lesson Plan
Grade: Date: 17/01/2026
Subject: Physics
Lesson Topic: recall and use W = ½ QV = ½ CV²
Learning Objective/s:
  • Recall the definition of capacitance and the relationship C = Q/V.
  • Derive and apply the energy‑storage formula W = ½ QV = ½ CV².
  • Convert between µF, F, V and J and calculate the energy stored in a given capacitor.
  • Identify and avoid common mistakes when using the energy formula.
  • Explain at least one real‑world application of capacitor energy (e.g., flash lamps, RC timing circuits).
Materials Needed:
  • Projector and screen
  • Whiteboard and markers
  • Printed worksheet with example problem and quick‑check questions
  • Scientific calculators (or student laptops with calculator app)
  • Diagram of a parallel‑plate capacitor (handout or slide)
  • Clicker/online quiz tool for concept checks
 Introduction:

Begin with a short video clip of a camera flash to hook interest and ask: “What stores the energy that powers that flash?” Connect to prior knowledge of charge and voltage, then state that today students will master the formula for energy stored in a capacitor and be able to use it in real‑world contexts.
Lesson Structure:
  1. Do‑Now (5 min): Quick written question – “If C = 10 µF and V = 5 V, what is Q?” Students submit answers on sticky notes.
  2. Mini‑lecture & derivation (10 min): Review C = Q/V, then step through the integration to obtain W = ½ QV = ½ CV², highlighting the ½ factor.
  3. Guided practice (12 min): In pairs, work through the 47 µF, 12 V example; teacher circulates, prompting unit conversion and formula substitution.
  4. Concept‑check quiz (5 min): Clicker questions on common mistakes (e.g., forgetting the ½, using source voltage).
  5. Application discussion (8 min): Brief case studies – flash lamp energy and RC timing circuits – students suggest why energy matters.
  6. Exit ticket (5 min): Write one real‑world example where capacitor energy is critical and calculate the stored energy using given values.
Conclusion:

Summarise the three equivalent forms of the energy equation and stress the importance of correct unit conversion. Collect exit tickets as a retrieval check and assign homework: complete a worksheet with two additional capacitor‑energy problems, including a brief explanation of a practical application.