LuduminaMG-04 · MG-U2 · Planned
Motor effect and Fleming’s left-hand rule
Learning objectives
Predict conductor-force direction; calculate force for a perpendicular conductor; identify factors controlling magnitude.
8463 §§4.7.2.2 / 8464 §§6.7.2.2
DfE single-science pp.41–42 / Combined pp.34–35. Evidence checked 30 September–1 October 2026. Skills: WS1.2; MS3b,3c,5b.
Explanation
The motor effect is a force on a current-carrying conductor in a magnetic field. Field, conventional current and force directions are mutually perpendicular in the standard setup. The supplied F = BIl relation assumes the conductor is perpendicular to the field.
Concepts, equations and units: F=BIl at 90°; N,T,A,m; left-hand field/current/force directions; conventional current.
Prediction, demonstration and game exercise
Predict, observe, explain
Reverse current and field separately; observe force reversal and compare two lengths.
Planned learner game exercise
Set current, field and wire length to move a cargo rail in a specified direction.
Independent practice
Three F/B/I/l calculations and two direction checks.
Original practice example · Shared Higher
A perpendicular wire has B = 0.20 T, I = 3.0 A and length 0.10 m in the field. Find force.
Show working and model answer
Working / reasoning
F = BIl = 0.20 × 3.0 × 0.10.
Answer
0.060 N.
Exit check and success criteria
Two calculations and both orientations correct; applicability condition stated.
During practice, compare the prediction with evidence and give an error-specific prompt. The exit item uses a fresh context or fresh values, answered independently.
Misconceptions, practical links and mastery
Check these misconceptions
Force always along current; use electron flow as conventional-current direction; same formula valid for parallel orientation.
Practical preparation
Optional teacher-led low-voltage motor-effect demo; no RP.
Virtual preparation and revision only. Required hands-on activities and school records remain separate.
Proposed mastery
0: not yet evidenced. 1: supported. 2: independent exit criteria met. 3: successful changed-context transfer. Advance at 2; revisit with fresh retrieval. These are not GCSE grades.