Electromagnetic Induction

4.5.1 Describe an experiment to demonstrate electromagnetic induction

Electromagnetic induction is the process where a changing magnetic field creates an electric current. This principle forms the basis of many electrical devices. This section details an experiment to demonstrate this phenomenon.

Aim

To demonstrate the principle of electromagnetic induction by observing the generation of an electric current in a coil of wire when exposed to a changing magnetic field.

Apparatus

• A coil of wire (e.g., 50 turns)
• A bar magnet
• A galvanometer
• Connecting wires
• A conducting path (e.g., a copper strip or a piece of wire)

Procedure

1. Connect the coil of wire to the galvanometer using the connecting wires.
2. Position the bar magnet so that its North pole is inside the coil.
3. Slowly move the bar magnet into and out of the coil.
4. Observe the galvanometer reading.
5. Repeat the experiment with the bar magnet moving rapidly into and out of the coil.

Observations

When the bar magnet is moved into and out of the coil, the galvanometer will show a deflection, indicating the generation of an electric current in the coil. The magnitude of the deflection will be proportional to the speed at which the magnet is moved.

Data Table

Trial	Speed of Magnet (Slow)	Galvanometer Reading
1	Slow
2	Slow
3	Fast
4	Fast

Analysis

The deflection in the galvanometer indicates the flow of electric current in the coil. This current is generated due to the changing magnetic flux through the coil. When the magnet moves into the coil, the magnetic flux increases, inducing a current. When the magnet moves out of the coil, the magnetic flux decreases, also inducing a current. The rate of change of magnetic flux is directly proportional to the magnitude of the induced current.

Conclusion

The experiment successfully demonstrates the principle of electromagnetic induction. By moving a magnet through a coil of wire, a changing magnetic field is created, which in turn induces an electric current in the coil. This confirms Faraday's law of electromagnetic induction.