This question focused on electromagnetic induction. Very often in these types of questions, students are asked to describe experiments to demonstrate Faraday’s and Lenz’s laws.

To Demonstrate Electromagnetic Induction

Faraday’s law of electromagnetic induction states that when there is a change in the magnetic flux linking a coil, an emf is induced in that coil. The strength of the emf is proportional to the rate of change of the flux linking the coil.

Method:

• Set up a circuit, as shown above.
• Move the magnet towards the coil.

Observations / Conclusion:

When the magnet is moving, a current is shown on the galvanometer, indicating that the changing magnetic field is creating an emf, as stated in Faraday’s law. The faster the magnet moves, the greater the current.

To demonstrate Lenz’s law:

Lenz’s law states that the direction of an induced current is such as to oppose the change causing it.

Method:

• Set up a circuit, as shown above.
• Move the magnet towards the loop and then away from it.

Observations/ Conclusion:

The loop always moves in the same direction as the magnet, indicating that a current is flowing in the loop, which opposes the change, as stated in Lenz’s law.