Lesson Plan

• Describe the microscopic expression I = Anvq and the physical meaning of each variable.
• Calculate drift speed of charge carriers from given current, area, number density and charge.
• Analyse how variations in A, n, v or q affect the magnitude of electric current.
• Apply the expression to solve typical A‑Level physics problems involving conductors.

• Projector or interactive whiteboard
• Slide deck showing derivation and diagram of a conductor cross‑section
• Worksheet with example problem and space for calculations
• Scientific calculators (or computer simulation tool)
• Rulers/compass for sketching cross‑sections (optional)
• Whiteboard and markers

Begin with a quick demonstration of how an electric signal appears instantly at the far end of a long wire, prompting students to wonder why the individual electrons move so slowly. Review the definition of electric current as charge per unit time and ask learners to state one factor that influences current. Clarify that by the end of the lesson they will be able to use the microscopic formula I = Anvq to predict those effects.

1. Do‑now (5') – short quiz on the macroscopic definition of current and units.
2. Mini‑lecture (10') – derive I = Anvq, explain each symbol, and display the suggested cross‑section diagram.
3. Guided practice (12') – work through the copper‑wire drift‑speed example in pairs, completing the calculations on the worksheet.
4. Conceptual discussion (8') – think‑pair‑share on how changing A, n, v, or q would double the current; record responses on the board.
5. Interactive simulation (10') – use a PhET‑style applet to vary parameters and observe the resulting current in real time.
6. Check for understanding (5') – exit ticket: write the expression I = Anvq and list one practical way to increase current in a circuit.

We revisited the microscopic origin of electric current, reinforcing how each parameter contributes to the overall flow of charge. Students completed an exit ticket that demonstrated their grasp of the formula and its implications. For homework, assign a problem calculating drift speed in an aluminium wire and a brief explanation of how increasing the cross‑sectional area would affect the current.