Force on a current-carrying conductor sim
Predict with Fleming's left-hand rule which way a copper rod on two rails between magnet poles will roll, switch on and watch it, then swap the supply's leads, turn the magnet over or both; hold the rod with a force sensor to plot force against current, work out F = BIL (GCSE Higher tier), and watch an a.c. current move a loudspeaker's cone in and out.
Electromagnetism: the motor effect · covers the O-Level, IGCSE, GCSE topic
What the sim shows
Model. F = BIL at right angles, with B = 0.10 T (chosen) only between the poles, L = 50 mm (the poles' width), directions by F = I L × B worked in the frame the student sees (Fleming's left-hand rule). The current: the shared circuit model, 3.0 V supply (0.2 Ω inside), leads, ammeter, rails and rod 0.004 Ω, and a 0 to 20 Ω rheostat; the page refuses more than 3.0 A. The rod rolls without slipping (a = F ÷ 1.5 m), no friction, no back e.m.f. Force sensor to 0.1 mN with a seeded scatter of ±0.3 mN. Loudspeaker: a.c. current i = I₀ sin 2πft, cone movement 15 mm per ampere, no resonance. Nothing runs on its own: the rod rolls when you switch on, the cone moves when you switch the signal generator on.
- The copper rod (rod on rails) or the loudspeaker's dust cap (loudspeaker)
- Rails, magnets on a steel yoke, supply, switch, rheostat, ammeter, force sensor, signal generator, loudspeaker
Use it in your lessons
- Try it here: anyone can unlock 2 figures free, and a free account unlocks up to 5. Runs on a laptop, a Chromebook or a phone; nothing to install.
- Present it and share student links with the teacher plan, from US$5 a month, billed yearly.
- Put it on your own website or LMS for US$9, paid once, or every sim from US$29 a month.
Free guide: 12 practicals as sims, and how to run one in a lesson →
Need a version for your exact set-up? Have one made: US$49 a figure in an order of 5.
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