| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Physics |
| Lesson Topic: define magnetic flux density as the force acting per unit current per unit length on a wire placed at right- angles to the magnetic field |
Learning Objective/s:
- Define magnetic flux density and express its relationship to force, current, and length.
- Apply B = F⁄(I L) to calculate magnetic flux density in quantitative problems.
- Explain the direction of the magnetic force using Fleming’s left‑hand rule.
- Distinguish between a magnetic field and the force it exerts on a current‑carrying conductor.
- Interpret the tesla unit and its dimensional formula.
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Materials Needed:
- Projector or interactive whiteboard
- PowerPoint slides with diagrams
- Worksheet with practice problems
- Fleming’s left‑hand rule handout
- Calculators for each student
- Demonstration set: current‑carrying wire, magnet, ammeter, ruler
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Introduction:
Begin with a quick demonstration of a current‑carrying wire being deflected by a magnet to capture interest. Review prior knowledge of force, current, and magnetic fields, reminding students of vector concepts. State that by the end of the lesson they will be able to define magnetic flux density, calculate it, and predict the force direction.
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Lesson Structure:
- Do‑now (5'): Students answer a short question on forces in magnetic fields from the previous lesson.
- Mini‑lecture (10'): Present the definition of B, derive F = I L B, and discuss units and dimensions.
- Demonstration (8'): Show the wire‑magnet setup and use Fleming’s left‑hand rule to predict the force direction.
- Guided practice (12'): Work through the worked example together, then have students solve similar problems in pairs using the worksheet.
- Check for understanding (5'): Quick exit‑ticket quiz with one calculation and one conceptual question.
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Conclusion:
Summarise that magnetic flux density links force, current, and length when the wire is perpendicular to the field, and its unit is the tesla. Ask students to complete an exit ticket calculating B for a new scenario. Assign homework to finish additional problems from the textbook chapter on magnetic forces.
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