Lesson Plan

• Describe the concept of electromotive force (e.m.f.) and the role of polarity in series circuits.
• Apply the sign‑convention to assign positive or negative values to each source.
• Calculate the combined e.m.f. of multiple sources using the algebraic sum formula.
• Analyse circuit diagrams to determine the net direction of the e.m.f.
• Identify and avoid common mistakes when adding e.m.f. values.

• Projector or interactive whiteboard
• PowerPoint slides with series‑circuit diagrams
• Worksheet containing example tables and practice questions
• Set of AA cells (or battery pack) for a live demonstration
• Multimeter (optional) to measure voltage
• Whiteboard and markers

Begin with a quick question about how flashlights work to hook students’ interest. Review the difference between series and parallel connections that they learned last week. Explain that by the end of the lesson they will be able to determine the net voltage of any series arrangement and state the success criteria.

1. Do‑now (5'): short quiz on series vs. parallel circuits (written).
2. Mini‑lecture (10'): introduce e.m.f., polarity, and the formula 𝓔ₜₒₜₐₗ = Σ𝓔ᵢ with sign‑convention; show suggested diagram.
3. Guided practice (12'): work through Example 1 (all aiding) and Example 2 (one opposed) on the board, modelling each step.
4. Collaborative activity (10'): pairs complete the worksheet’s practice questions, recording signs and sums.
5. Check for understanding (8'): clicker/hand‑raise questions on common mistakes and polarity identification.
6. Summary & misconceptions (5'): recap key steps and address the three listed errors.

Summarise the four‑step procedure for finding the combined e.m.f. and ask a few students to restate it in their own words. Have each pair write an exit ticket with one new example they could solve at home. For homework, assign the three practice questions from the source plus an extra problem involving four cells with mixed polarity.