Consider metal ring kept on a horizontal plane . A bar magnet is held above the ring with its length along the axis is held above the ring with its length along the axis of the ring . If the magnet is dropped freely the acceleration of the falling magnet is : ( g is accelration due to gravity )

Options

A. More than g
B. Equal to g
C. Less than g
D. Depends on mass of magnet

Answer

**Step-by-Step Solution:**

1. **Understanding the Setup**: We have a metal ring placed on a horizontal plane and a bar magnet held above it. The magnet is oriented such that its length is along the axis of the ring.

2. **Initial Condition**: When the magnet is initially far from the ring, it experiences free fall under the influence of gravity, meaning it accelerates downwards at \( g \) (acceleration due to gravity).

3. **Induction Phenomenon**: As the magnet approaches the ring, the magnetic flux through the ring changes. According to Faraday's law of electromagnetic induction, a change in magnetic flux induces an electromotive force (EMF) in the ring.

4. **Direction of Induced EMF**: The induced EMF generates a current in the ring, which in turn produces its own magnetic field. By Lenz's law, this induced magnetic field opposes the change in flux. If the magnet is falling, the induced current will create a magnetic field that opposes the falling magnet's motion.

5. **Effect on Acceleration**: As the magnet falls closer to the ring, the induced current creates a magnetic force that opposes the magnet's fall. This opposing force reduces the net force acting on the magnet, resulting in a decrease in its acceleration.

6. **Conclusion**: Therefore, the acceleration of the falling magnet is less than \( g \) due to the opposing force created by the induced current in the ring.

**Final Answer**: The acceleration of the falling magnet is less than \( g \).

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