Lesson Plan

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Lesson Plan
Grade: Date: 17/01/2026
Subject: Physics
Lesson Topic: understand that a force might act on a current-carrying conductor placed in a magnetic field
Learning Objective/s:
  • Describe the magnetic Lorentz force on moving charges and how it produces a force on a current‑carrying conductor.
  • Apply the formula F = I L B sinθ to calculate the magnitude of the force on a straight wire.
  • Use Fleming’s left‑hand rule to determine the direction of the force.
  • Predict how changes in current, length, magnetic field strength, or angle affect the force.
  • Explain the relevance of this principle in devices such as electric motors and railguns.
Materials Needed:
  • Projector or interactive whiteboard
  • Slide deck with diagrams and animation of Fleming’s left‑hand rule
  • Printed worksheet with example problem and space for calculations
  • Straight piece of wire, ruler, and a small bar magnet for a quick demo
  • Calculator (or calculator app)
  • Whiteboard and markers
 Introduction:
Begin with a quick demonstration: hold a magnet near a current‑carrying wire and ask students what they observe. Recall that magnetic fields exert forces on moving charges, a concept covered in previous lessons on electromagnetism. Explain that today they will predict both the size and direction of the force on a conductor using the Lorentz‑force equation and Fleming’s left‑hand rule. Success will be measured by correctly solving the sample problem.
Lesson Structure:
  1. Do‑Now (5'): Students answer a short question on magnetic forces on moving charges displayed on the board.
  2. Mini‑lecture (10'): Review Lorentz force, derive F = I L B sinθ, and introduce Fleming’s left‑hand rule with diagram.
  3. Guided demonstration (8'): Teacher shows wire‑magnet demo; students predict direction using the left‑hand rule, then confirm.
  4. Collaborative problem solving (12'): In pairs, students work through the example problem, calculate magnitude and state direction; teacher circulates.
  5. Quick check (5'): Whole‑class poll of answers using clickers or a show of hands.
  6. Summary & reflection (5'): Highlight key take‑aways and link to real‑world applications.
Conclusion:
Summarise that the magnetic force on a straight conductor depends on current, length, field strength and the sine of the angle, and that its direction is given by the left‑hand rule. For exit, each student writes one real‑world device that uses this principle on a sticky note. Homework: complete a worksheet with two additional force‑calculation problems.