Concept simulationPhysics

Electromagnetic Induction

Drag a magnet toward and away from a coil and watch the induced current respond — and reverse.

The idea to rememberA coil reacts only to a changing magnetic flux, and it always reacts so as to oppose that change. Same position but opposite motion gives opposite current; no motion gives nothing.

This is a conceptual visualisation built to show how the physics behaves — it deliberately shows direction and relative strength, not exact numerical values.

What this electromagnetic induction simulation shows

This electromagnetic induction simulation turns Faraday's and Lenz's laws into a direct interaction. Move the bar magnet toward the coil, pull it away, or hold it still and watch the galvanometer, circuit current and magnetic-flux cues respond together.

The simulation is intentionally qualitative. It shows the direction and relative strength of the induced effect without presenting invented voltage, current or magnetic-flux values.

How to explore the concept

Stop the automatic sweep and drag the magnet slowly toward the coil.
Hold the magnet still near the coil and observe that the induced current falls to zero.
Pull the magnet away and watch the current direction and galvanometer deflection reverse.
Repeat the motion faster and compare the relative strength of the response.

What to observe and learn

Watch for these changes

The galvanometer deflects in opposite directions when the same magnet position is crossed in opposite directions.
Faster motion creates a stronger visible response because the magnetic flux changes more rapidly.
The current disappears when the magnet stops, even if the magnet remains close to the coil.
The induced response opposes the change: the coil resists approach and resists separation.

Physics exam connections

Distinguishing magnetic field from changing magnetic flux.
Predicting current direction when a magnet approaches or recedes.
Understanding why faster motion increases induced emf.
Applying Lenz's law as a consequence of energy conservation.

Theory behind the simulation

Faraday's law states that an emf is induced when magnetic flux through a circuit changes. A strong but stationary magnetic field does not continuously induce current; the essential condition is changing flux.

Lenz's law gives the direction of the induced current. The magnetic effect produced by that current opposes the change that caused it. This is why approaching and receding motion produce opposite current directions.

What the model simplifies

This simulation is designed for conceptual understanding. Its states follow the standard theory, while deliberately avoiding uncalibrated numerical readouts.

The field and current strengths are relative visual indicators, not measured values.
The coil and bar magnet are treated as an idealised system.
Circuit resistance, self-inductance and detailed magnetic-field geometry are outside this conceptual view.

Frequently asked questions

Why is there no induced current when the magnet stops?

When the magnet is stationary relative to the coil, the magnetic flux through the coil is no longer changing. Faraday's law therefore predicts no sustained induced emf or current.

Why does the galvanometer reverse when the magnet moves away?

The direction of the magnetic-flux change reverses. Lenz's law requires the induced current to reverse so that its magnetic effect continues to oppose that change.

Does the magnet's position alone determine the induced current?

No. The induced current depends on how magnetic flux is changing. At the same position, approach and recession produce opposite current directions, while a stationary magnet produces no current.

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