Magnet

What is a Magnet?

A magnet is a material or artificial setup that can produce a magnetic field around it. Due to the magnetic field, a magnet can attract ferromagnetic materials (e.g. iron filings) and attract or repel any other magnet. Magnets, suspended through a string, always point towards the north-south direction. A magnet always comes with a pair of magnetic poles, which cannot be separated. These are often referred to as “north pole” and “south pole”. Like poles repel one another whereas opposite poles attract. Some materials naturally behave like magnets whereas it is also possible to manufacture artificial magnets.  

Properties of Magnet

Magnets have distinctive and interesting properties as follows,

  • Attractive property of magnet: A magnet attracts ferromagnetic materials like iron, nickel, and cobalt.

  • Directive property of magnet: If a magnet is suspended from rigid support such that it can rotate freely, the magnet always points towards the north-south direction. 

  • Poles of a magnet: Magnets have two poles, where the strength of the magnetic field is the strongest. Magnetic poles exist in pairs. No matter how small a magnet is, it is impossible to separate one pole.

  • Like poles always repel each other but opposite poles attract.

  • The magnetic force (attraction or repulsion) between two objects is inversely proportional to the distance between them. The force is stronger when the objects are close.

Magnetized and Ferromagnetic Material

Materials that have properties like a magnet are called magnetized materials. These can naturally appear in the Earth or manufactured. Magnetite is a naturally magnetized substance. 

Some materials are attracted by magnets and can be magnetized via different processes. These are called ferromagnetic materials. Some examples are iron, cobalt, and nickel.

Types of Magnet

Most magnets used in research and technology are artificially made into different sizes and shapes from magnetized materials. The processes and sources of magnetism widely vary. Some commonly used magnets are,

  • Bar magnet

  • Magnetic needle

  • Horseshoe magnet

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Based on the source of magnetism, magnets can be categorized into the following types,

Permanent Magnet: These magnets are made from magnetized materials and once magnetized, they do not lose their magnetic properties generally. Such magnets may be naturally appearing as rare-earth substances or various chemical compounds. However, due to high temperature and stress, even permanent magnets can lose magnetic properties. Some examples are,

  • Alnico (an alloy of Aluminum, Nickel, and Cobalt)

  • Ferrite or ceramic (iron oxides mixed with nickel, cobalt or strontium)

  • Samarium Cobalt

  • Neodymium Iron Boron (NdFeB)

Temporary Magnet: These magnets are manufactured by exposing ferromagnetic materials to a magnetic field. When the magnetic field is removed, the materials lose their characteristics of a magnet. These magnets are made up of various soft materials. Some temporary magnet examples are iron and iron alloys, nails, and paper clips.

Electromagnet: Electromagnets are strong magnets, consisting of wires closely wrapped around an iron core. When a current is made to flow through the wires, it behaves like a magnet. As soon as the current is switched off, the magnetic behavior goes away. 

Experiment Depicting Poles of a Magnet

The figure shows a bar magnet placed on a plane, on which some iron filings are sprinkled. Since iron is a 

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Ferromagnetic material, the bar magnet attracts the filings. It is seen that the filings get arranged in a strange pattern. Most of the filings accumulate near the ends of the magnet. These ends are called the magnetic poles. 

If the bar magnet is suspended by a string, it rotates and gets fixed in the north-south direction. The north-pointing pole is named the “north pole” and the pole, pointing geographic south, is named the “south pole” of the magnet. North and south poles attract each other however north-north and south-south poles repel. 

Applications of Magnet

Magnets are widely used in daily life, science, and technology. Some uses are,

  • Permanent magnets are used in hard drives, television, cars, motors, refrigerators.

  • Electromagnets are very important in electric and mechanical devices. Motors, generators, speakers, transformers, and many more devices require electromagnets.

  • Temporary magnets are often used in manufacturing electromagnets.

Did you know?

  • The Earth has a magnetic field. It can be considered as a very large bar magnet, with its north pole being located near the geographical north pole and its south pole being located near the geographical south pole. Due to this magnet, all magnets on the Earth point in the geographic north-south direction. 

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  • The first magnetic material was discovered in the Magnesia region of Asia. It was named “Magnetite” (Fe3O4). There is another story that suggests that the material was discovered by a shepherd named Magnes, who observed his shoe nails to stick with some rocks (apparently containing magnetite).

  • Previously, magnetite was used by sailors in the oceans as a compass. Therefore, it is also known as “leading stone” or “lodestone”.

FAQ (Frequently Asked Questions)

1. What are Magnets Made of? Write Down the Types of Magnets.

Magnets are made of different magnetized materials. Depending on the process of magnetization, magnets have mainly three categories which are permanent magnet, temporary magnet, and electromagnet.

Permanent magnets do not lose their magnetic property easily. Electromagnets are made up of current flowing through a coil of wires wound about an iron core. A temporary magnet is made by exposing a ferromagnetic material in a magnetic field. When the magnetic field is removed, the magnet loses its characteristics.

2. Write any Two Properties of a Magnet.

Magnets attract ferromagnetic materials and attract or repel other magnets. Magnets, suspended through a string, always point towards the north-south direction. A magnet always comes with a pair of magnetic poles, which cannot be separated. These are often referred to as “north pole” and “south pole”. Like poles repel one another whereas opposite poles attract.