| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Physics |
| Lesson Topic: Describe the deflection of α-particles, β-particles and γ-radiation in electric fields and magnetic fields |
Learning Objective/s:
- Describe how α, β (electron and positron), and γ radiation are deflected in uniform electric fields.
- Explain how charge, mass, and velocity determine the curvature of particle paths in magnetic fields using the Lorentz‑force equation.
- Compare the deflection behaviours of the three radiation types and predict direction and radius of curvature in given field conditions.
- Apply the concepts to solve typical exam questions involving calculation of radius of curvature.
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Materials Needed:
- Projector and screen for diagrams
- Whiteboard and markers
- Printed handouts with comparison tables and sample questions
- Simulation software (e.g., PhET) showing particle trajectories
- Worksheets for pair and group activities
- Demonstration kit with parallel‑plate capacitor and small electromagnet (if available)
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Introduction:
Begin with a short video of charged particles being bent in a magnetic field to spark curiosity. Review prior knowledge of charge, mass and the Lorentz force, then state that by the end of the lesson students will be able to describe and predict the deflection of α‑particles, β‑particles and γ‑radiation in both electric and magnetic fields.
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Lesson Structure:
- Do‑now (5') – Quick written question on the direction of electric force for positive and negative charges.
- Mini‑lecture (10') – Present properties of α, β, γ and the equations F = qE and F = qv×B with projector diagrams.
- Interactive simulation (12') – Pairs explore a PhET simulation of particle trajectories in electric and magnetic fields and record observations.
- Guided practice (10') – Work through a sample exam question, calculating radii of curvature for α‑ and β‑beams.
- Group comparison activity (8') – Using handouts, groups fill a table summarising deflection direction and curvature for each radiation type.
- Quick check (5') – Exit quiz (Kahoot) with three multiple‑choice items to assess understanding.
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Conclusion:
Summarise that α‑particles show slight curvature, β‑particles curve sharply (with opposite rotation for β⁺), and γ‑rays remain undeflected in both fields. Ask students to write one key takeaway on a sticky note as an exit ticket, and assign homework to complete a worksheet calculating radii for different field strengths.
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