HS2 Physics Chapter 6 ELECTROMAGNETIC INDUCTION : Experiments

 

Experiment: Demonstration of Electromagnetic Induction

Objective:

To demonstrate the phenomenon of electromagnetic induction and verify Faraday’s laws.

Apparatus Required:

• A solenoid or coil of wire

• A galvanometer

• A strong bar magnet

• Connecting wires

• Stand and clamps

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Procedure:

1. Setup:

   • Connect the coil to the galvanometer using connecting wires.

   • Fix the coil vertically using a stand.

   • Ensure the galvanometer is zeroed and sensitive enough to detect small currents.

2. Demonstration Steps:
   a) Moving Magnet into the Coil:

   • Quickly insert the north pole of the bar magnet into the coil.

   • Observe the galvanometer. It should show a deflection, indicating an induced current.

   b) Stationary Magnet:

   • Hold the magnet stationary inside the coil.

   • The galvanometer shows no deflection, indicating no current is induced when there is no change in magnetic flux.

   c) Withdrawing the Magnet:

   • Pull the magnet out of the coil.

   • The galvanometer deflects in the opposite direction, showing a reverse current is induced.

   d) Changing the Speed:

   • Insert and remove the magnet more quickly.

   • The deflection increases, indicating a larger induced EMF with a faster rate of change of magnetic flux.

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Observations:

• A current is induced in the coil only when there is a relative motion between the magnet and the coil.

• The direction of the current changes with the direction of motion.

• Faster motion causes greater deflection, confirming that the induced EMF is proportional to the rate of change of magnetic flux.

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Conclusion:

This experiment verifies Faraday’s laws of electromagnetic induction:

• An EMF is induced when the magnetic flux linked with a circuit changes.

• The magnitude of the induced EMF is proportional to the rate of change of flux.

• The direction of induced EMF opposes the cause producing it (Lenz’s law).