Electromagnetic Induction 3D Simulation

Electromagnetic induction happens when a changing magnetic field produces an electric current or voltage in a conductor. In this simulation, a bar magnet moves through a solenoid, which is a coil of wire. As the magnet moves, the magnetic field passing through the coil changes. This changing magnetic field induces an electromotive force, or EMF, in the coil.

The simulation above demonstrates the key idea that induction depends on change. If the magnet is stationary, the magnetic field through the coil is not changing, so little or no EMF is produced. When the magnet moves into or out of the solenoid, the magnetic field through the coil changes more quickly, and a larger EMF is produced, by Faraday's La.

The direction of the induced EMF depends on the direction of motion and the orientation of the magnet. If the north pole enters the solenoid first, the induced voltage has one direction. If the south pole enters first, or if the magnet moves in the opposite direction, the induced voltage reverses. This follows Lenz’s law, which says that the induced current acts in a direction that opposes the change that produced it.

Use the simulation by moving the magnet manually through the solenoid. Watch how the voltage changes as the magnet enters, passes through, and leaves the coil. Notice that the voltage is largest when the magnet is moving near the ends of the solenoid.

Try oscillation mode to move the magnet back and forth repeatedly. The voltage alternates between positive and negative values, showing how changing magnetic flux can produce an alternating EMF.

Try free fall mode to drop the magnet through the solenoid. Since the magnet speeds up as it falls, the induced voltage changes depending on how fast the magnet is moving.

Change the solenoid length and compare the voltage graphs. This helps you explore how the coil structure affects the induced EMF.

Reverse the poles of the magnet and observe how the voltage graph changes direction. This shows that the polarity of the induced EMF depends on the direction of the magnetic field.