Question

What is magnetic induction ? Describe in detail how a steel needle can be magnetised by induction.

Answer 1

Hint: The generation of an electromotive force across an electrical conductor in a changing magnetic field is known as electromagnetic or magnetic induction. Induction was discovered in 1831 by Michael Faraday, and it was mathematically defined as Faraday's law of induction by James Clerk Maxwell. The direction of the induced field is described by Lenz's law. Faraday's law was eventually extended to become the Maxwell–Faraday equation, one of Maxwell's four electromagnetic equations.

Complete step by step solution:
The generation of an electromotive force across an electrical conductor in a changing magnetic field is known as magnetic induction. Magnetic induction is a technique for converting magnetic materials such as steel and iron into magnets. In other words, magnetic induction is the process of generating magnetism in a piece of magnetic material that is not normally magnetic.
The steps are as follows:
1. Place the steel needle in close proximity to a powerful magnet without touching it.
2). The steel needle bar transforms into an induced magnet, with the end closest to the magnet having the opposite polarity as the magnet.
3). As a result, the iron needle is drawn to the permanent magnet and attached to it. Magnetic induction explains how magnetic materials are attracted to magnets.
4) Induced magnetism is a transient phenomenon. The magnetic substance will generally lose its induced magnetism if the permanent magnet is removed.


Note: Eddy currents are circular currents produced by induction in electrical conductors travelling through a constant magnetic field or stationary conductors within a changing magnetic field. In planes perpendicular to the magnetic field, eddy currents flow in closed loops. Eddy current brakes and induction heating systems are two examples of where they can be used. Eddy currents produced in the metal magnetic cores of transformers, AC motors, and generators, on the other hand, are undesirable because they lose energy (known as core losses) as heat in the metal resistance. To minimise eddy currents, these devices' cores employ a variety of techniques: