Lesson Plan

• Describe how the magnetic force on moving charge carriers creates a transverse electric field (Hall voltage).
• Derive the Hall‑voltage expression \(V_H = \dfrac{BI}{ntq}\) from the equilibrium condition.
• Apply the formula to calculate an unknown quantity (e.g., carrier density) from measured values.
• Identify and correct common misconceptions such as using the width instead of thickness or incorrect unit conversion.

• Projector and screen
• Whiteboard and markers
• Hall‑effect demonstration kit (thin metal strip, power supply, electromagnet, digital voltmeter)
• Student worksheet with derivation steps and practice problems
• Scientific calculators
• Printed handout of typical values and units

Begin with a quick demonstration of a hidden “sea of electrons” that can be measured without opening a circuit. Review the Lorentz force on a moving charge and ask students to predict the direction of the force on electrons in a magnetic field. Explain that today they will see how this force leads to a measurable Hall voltage and will be able to use the derived formula to find carrier densities.

1. Do‑now (5 min): Write the Lorentz force on a charge and state the expected direction of the force for electrons in a magnetic field. Collect responses to gauge prior knowledge.
2. Mini‑lecture (10 min): Derive \(F = I\mathbf{L}\times\mathbf{B}\) and introduce the Hall effect with a labelled diagram.
3. Guided derivation (15 min): In pairs, students work through the step‑by‑step worksheet to obtain \(V_H = \dfrac{BI}{ntq}\). Teacher circulates, prompting the substitution of \(v_d\) and cancellation of width.
4. Live demonstration (10 min): Set up the Hall‑effect kit, vary \(B\) and \(I\), record the resulting \(V_H\). Students plot \(V_H\) vs \(B\) to see linearity.
5. Application problem (10 min): Solve the provided copper‑strip example, calculate carrier density, and discuss how the result compares with known values.
6. Misconception check (5 min): Quick quiz on common pitfalls (thickness vs. width, sign of \(q\), unit conversion). Review answers instantly.
7. Summary & exit ticket (5 min): Students write one sentence summarising the origin of the Hall voltage and one lingering question; submit before leaving.

Recap the chain from magnetic force to charge separation and the final Hall‑voltage expression. Collect exit tickets to confirm understanding and assign homework: complete the worksheet’s additional problems and research a real‑world Hall‑sensor application.