Lesson Plan

• Describe how voltage and current are distributed across each lamp in a parallel circuit.
• Explain why parallel wiring gives uniform brightness, independent operation, and greater safety.
• Calculate equivalent resistance and total current for series and parallel lamp arrangements.
• Compare series and parallel lighting circuits in terms of efficiency and fault tolerance.
• Apply the concepts to predict circuit behaviour when a lamp fails.

• Projector or interactive whiteboard
• PhET circuit simulation (or similar) on computers/tablets
• Breadboard, three identical 60 W lamps, 240 V power supply
• Multimeters (voltage & current)
• Worksheets with calculation tasks
• Calculator and pens

Begin with a quick question: “What happens to the brightness of lamps if they are connected in series?” Use students’ prior knowledge of series circuits to highlight the problem of uneven voltage division. State that today they will discover why electricians prefer parallel wiring for lighting and how to evaluate its benefits.

1. Do‑now (5'): Students answer the opening question on a sticky note and submit.
2. Mini‑lecture (10'): Present key concepts of parallel circuits – same voltage across branches, current division, equivalent resistance formula.
3. Hands‑on demo (15'): Build a series and a parallel set‑up with the three lamps; measure voltage across each lamp and observe brightness differences.
4. Guided calculation activity (10'): Using the worksheet, students compute resistance, total current, and power per lamp for both configurations.
5. Think‑pair‑share (5'): Groups list the advantages of parallel wiring and fill a comparison table.

Recap the four main advantages of parallel lighting: uniform brightness, independent operation, control flexibility, and safety/efficiency. Ask each student to write one advantage on an exit ticket. For homework, assign a problem set requiring analysis of a mixed series‑parallel lighting circuit.