Electromagnetic Induction (Faraday's Law)
Slide a bar magnet through a coil — adjust its speed, the coil's turns, and the magnet's strength to see the induced EMF rise, peak, flip sign as the magnet passes through, and fade as it recedes.
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What you can adjust
- Magnet speed
- 0.2 – 8 m/s
- Coil turns (N)
- 10 – 500 turns
- Magnet strength (Φ0)
- 0.001 – 0.02 Wb
How fast the bar magnet slides along the coil's axis — a faster pass means a faster-changing flux, and Faraday's law says that means a bigger induced EMF.
Each turn of wire adds its own induced EMF in series — more turns means a proportionally bigger total EMF for the same changing flux.
The peak magnetic flux the magnet threads through the coil at closest approach — a stronger magnet means a bigger flux swing, and a bigger induced EMF.
About this simulation
What it shows
A bar magnet slides along the axis of a coil, and the voltage induced in the coil is drawn over time. It rises, passes through zero as the magnet crosses the middle, flips sign, and fades.
The key idea
A changing magnetic flux through a coil induces a voltage: EMF = −N dΦ/dt. More turns, a faster magnet or a stronger magnet all give a bigger voltage, and the sign flips because the flux first rises and then falls.
Try this
Double Coil turns (N) from 100 to 200: the induced voltage doubles for the same pass of the magnet.
The flux through the coil is modelled with a smooth bell-shaped curve, a standard simplification. The magnet moves at a constant speed.