LuduminaMG-06 · MG-U2 · Planned
Loudspeakers and headphones
Learning objectives
Explain moving-coil conversion from changing current to pressure variations.
8463 §§4.7.2.4 / No Trilogy counterpart
DfE single-science pp.41–42 / Combined pp.34–35. Evidence checked 30 September–1 October 2026. Skills: WS1.2,1.4,3.6; MS4a.
Explanation
A changing current in the loudspeaker coil produces a changing force in its magnetic field. The coil and cone vibrate, making pressure variations in air. Pitch follows oscillation frequency; increasing amplitude is a different change.
Concepts, equations and units: Motor effect; AC current A, frequency Hz; coil/cone displacement; no acoustic power formula.
Prediction, demonstration and game exercise
Predict, observe, explain
Show current trace, coil force and cone motion with consistent phase-labelled model.
Planned learner game exercise
Match electrical frequency to cone motion and sound-pressure waveform; diagnose reversed or missing components.
Independent practice
Explain a four-stage current→force→vibration→sound chain and interpret a waveform.
Original practice example · Separate Physics Higher
A loudspeaker is driven by an AC signal at 500 Hz in the model. What frequency is the cone’s driven oscillation?
Show working and model answer
Working / reasoning
The alternating force follows the drive signal; the model cone oscillates at the supplied drive frequency.
Answer
500 Hz.
Exit check and success criteria
All four links correct and sound frequency tied to drive frequency.
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
Sound carries the electrical current to the ear; loudspeakers use the generator effect; amplitude changes necessarily change pitch.
Practical preparation
Optional low-volume loudspeaker observation; 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.