Lesson Plan

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Lesson Plan
Grade: Date: 01/12/2025
Subject: Physics
Lesson Topic: use equations of the form x = x0 sin ωt representing a sinusoidally alternating current or voltage
Learning Objective/s:
  • Describe the sinusoidal representation x = x₀ sin(ωt+φ) and identify each symbol.
  • Calculate peak, RMS, period, and frequency for a given AC expression.
  • Analyse phase relationships and reactance of resistors, inductors, and capacitors in AC circuits.
  • Apply power formulas to determine apparent, real, and reactive power and the power factor.
Materials Needed:
  • Projector or interactive whiteboard
  • Slide deck with sinusoid and phasor diagrams
  • Worksheet with example calculations
  • Oscilloscope or simulation software (e.g., PhET)
  • Calculators
  • Whiteboard and markers
 Introduction:
Begin with a quick demonstration of a sine‑wave displayed on the oscilloscope, asking students what they notice about its shape and timing. Recall previous work on simple harmonic motion and the definition of frequency. Explain that today they will translate that knowledge into the language of alternating current, using the equation x = x₀ sin ωt and learning how to extract key quantities and power information. Success will be measured by correctly completing the worksheet and explaining phase relationships.
Lesson Structure:
  1. Do‑now (5'): Students sketch a sine wave and label amplitude, period, and frequency.
  2. Mini‑lecture (15'): Derive x = x₀ sin(ωt+φ), define symbols, and relate ω, f, T.
  3. Guided practice (10'): Work through the mains voltage example, calculate peak, RMS, period.
  4. Interactive simulation (10'): Use PhET or oscilloscope to observe phase shifts for R, L, C; discuss voltage‑current relationships.
  5. Group activity (15'): Calculate reactance X_L, X_C and power factor for given circuit parameters; complete worksheet.
  6. Quick check (5'): Exit ticket – one sentence summarising how phase angle affects real power.
Conclusion:
Summarise how the sinusoidal equation links amplitude, frequency, and phase to measurable AC quantities and power. Highlight the importance of RMS values and power factor in real‑world circuits. Collect exit tickets and assign homework to solve a set of AC circuit problems involving phasors and power calculations.