Chapter 25.2, Problem 18SSC

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To determine

To Explain:The direction in which the coil will swing relative to the magnet and the reason behind it.

Answer to Problem 18SSC

The changing magnetic field induces a current in the coil, which produces amagnetic field away from the magnet. This field opposes the field of the magnet and theforce between coil and magnet becomes repulsive.

Explanation of Solution

Introduction:

When the magnet is moved in the coil, the magnetic flux changes around the coil and it generates or induces filed in the coil as well. The fieldsin the coil and in the magnet are generated in opposite direction and they repel each other.

By varying the external magnetic flux, the voltage in a conductor is induced states by faraday’s law of induction.When magnet moved towards the coil quickly at a sudden, rate of flux change is greater than when magnet moves slowly so larger EMF is induced because of the fast movement of the coil.The varying magnetic field induces a current in the coil; this produces a magnetic field away from the magnet.This field opposes the magnet field, so that is why force in-between coil and magnet is repulsive. The coil will move away from the magnet.

Conclusion:

Due to the induced magnetic field in the coil because of the change in magnetic flux brought in by the movement of the magnet the coil moves away from the magnet.