| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Physics |
| Lesson Topic: describe the motion of a charged particle moving in a uniform magnetic field perpendicular to the direction of motion of the particle |
Learning Objective/s:
- Describe the circular motion of a charged particle in a uniform magnetic field perpendicular to its velocity.
- Explain how the Lorentz force leads to the magnetic force on a straight current‑carrying conductor.
- Calculate the radius of the particle’s trajectory and the magnetic force on a conductor using the appropriate formulas.
- Apply Fleming’s left‑hand rule to determine the direction of the magnetic force on a wire.
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Materials Needed:
- Projector and screen
- Whiteboard and markers
- Physics textbook (chapter on magnetic forces)
- Worksheet with example problems
- Diagram handout of particle motion and conductor
- Scientific calculators
- Computer with PhET magnetic field simulation
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Introduction:
Begin with a short video of a particle accelerator showing charged particles curving in a magnetic field, linking to students' prior study of Newton’s laws and vector cross products. Remind learners that magnetic forces are always perpendicular to the motion of a charge. Explain that by the end of the lesson they will be able to describe the motion, derive the radius formula, and predict the force on a current‑carrying wire.
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Lesson Structure:
- Do‑Now (5'): Quick question on applying the right‑hand rule to a moving charge.
- Mini‑lecture (10'): Introduce the Lorentz force, derive the simplified magnitude F = qvB, and obtain r = mv/(qB) and ω = qB/m.
- Demonstration (8'): Use a PhET simulation to show a charged particle’s circular path in a uniform B‑field; discuss observations.
- Guided practice (12'): Work through the proton‑radius example as a class, students calculate the radius step‑by‑step.
- Connect to current (8'): Derive F = I L B for a straight wire, introduce Fleming’s left‑hand rule, and annotate the diagram.
- Independent practice (12'): Students complete worksheet problems on particle radius and force on a conductor while the teacher circulates for feedback.
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Conclusion:
Summarise that magnetic forces cause uniform circular motion of charged particles and produce a net force on a current‑carrying conductor given by F = I L B. Ask each student to write one key formula on an exit ticket and briefly explain its physical meaning. For homework, assign textbook problems on cyclotron radius and magnetic force on wires to reinforce the concepts.
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