The bar magnet: Introduction, classification, properties, and uses

Introduction 

Since our childhood, we all have been a fan of magnets and especially by their properties to repel when placed parallel to another magnet in a particular manner and attract iron nails, iron shavings, and so on. It was quite surprising for a 10-year-old to wonder how a bar magnet can grab so many iron nails. Well, today, it’s time to decode the secret! If you’re interested to read everything about the bar magnet, make sure you stick by us till the end! 

What is a bar magnet? 

A bar magnet is one of the most popular types of magnets, which is rectangular in shape and made up of steel, iron, and other ferromagnetic composites, also known as a ferromagnetic substance that holds everlasting magnetic properties. The bar magnet has two sides donated as north and a south pole. When left freely, the magnet has the ability to align itself in a manner that the north pole is pointed towards the Earth’s magnetic north pole. In most ideal cases, the magnetic field at the center of a bar magnet is zero.

Types of the bar magnet 

There are majorly two types of the bar magnet: 

1. The rectangular bar magnet – The first on the list is the rectangular bar magnet which is mostly found in the engineering and the manufacturing industries. As compared to the other type, they have higher magnetic strength. 
2. The cylindrical bar magnet – The next and the last type of bar magnet is the cylindrical bar magnet which is also referred to as a rod magnet due to its shape. Since these hold excellent magnetism properties, they mostly find application in experimental, research, and educational uses. 

Classification of the bar magnet 

The bar magnets can be classified into two major groups primarily on the basis of how they got their magnetic properties and for how long they will sustain. Below, we have discussed the two groups; let’s have a look- 

1. Natural magnets – As the name suggests, natural magnets are a part of nature that is comparatively weak in their magnetic field. The most common example of natural magnets is lodestones. 
2. Artificial magnets – Since artificial magnets are produced by humans using machines, they have a high magnetic field. Note, when an artificial magnet is shaped in a predefined bar shape, it is termed the bar magnet. 

Properties of the bar magnet 

Like any permanent magnet, the bar magnet has the same properties. Below, we have written the properties of bar magnet, let’s have a look- 

• It has a south pole and a north pole at each end. In case the bar magnets broke, it still has both the south and north pole. No matter how many pieces it splits, it still has both the poles. 

• The magnetic lines of force inside bar magnet are the strongest near the poles. 
• When the 2 bar magnets are positioned close to one another, the same poles will repel each other; however, the opposite poles will tend to attract. 

• All the ferromagnetic materials will get attracted by the bar magnet. These ferromagnetic materials are nickel, iron, and cobalt. 

• In case the bar magnet is tied with a thread in the air, there’s no way it can come to rest until and unless the north pole and the south pole are placed in a north-south position. 

Uses of the bar magnet 

The following are the uses of the bar magnet- 

• In order to conduct magnetic experiments, bar magnets are commonly used as stirrers in research labs around the globe. 

• Apart from laboratories, bar magnets are an essential tool to conduct medical procedures. 

• Electronic devices, including radios, televisions, and telephones, consist of magnets. 

• To recollect scattered loose metals, irons, and nickel, many industries make use of bar magnets. 

• One primary application of bar magnets is that they are used to retain the magnetism property of magnets. 

Bar magnet magnetic field lines 

Imagine you’ve sprinkled tiny iron pieces or filling on a white paper along with a magnet bar in between. Every time you tap on the paper, the iron filings will be aligned around the magnet bar. Some of the properties of the magnetic field lines are- 

• The magnets’ magnetic field lines build a continuous closed loop. 

• The magnetic field lines do not have an intersection point. 

• The more the magnetic field lines, the stronger the magnitude will be 

Difference between the electromagnets and the bar magnets 

Although the bar magnets and the electromagnets have the same magnetic fields, there are certain differences between the two. Below, we have highlighted these differences. Let’s have a look- 

• The bar magnets are nothing but ferromagnetic materials; however, the electromagnets are wire coils that have a ferromagnetic core. In case the electric current passes through the electromagnets, they start to react like bar magnets. 

• Bar magnets do not depend on the external source to generate the magnetic field, unlike electromagnets which are mostly dependent on the external sources. 

• Since bar magnets are permanent magnets, they have a sustainable magnetic pull, whereas electromagnets do not have it since it is highly dependent on external factors. 

• The magnetic power of bar magnets remains the same. In contrast, in the case of electromagnets, it can vary depending upon various factors, including the electrons passing through, the material used, and so on. 

Define pole strength 

The magnetic pole has some strength through which it attracts magnetic materials. The pole strength;s SI unit is N. Tesla-1 with dimensions [LA]. 

Here is the formula to calculate the pole strength- P=W/I

Where, 

P is the magnetic pole strength 

W is defined as the work done 

I is electric current passing through the wire 

Conclusion 

In this article, we learned about the bar magnet and its properties. A bar magnet is rectangular in shape and made up of steel, iron, and other ferromagnetic composites. The bar magnet has two poles, namely a north and a south pole. A freely hanging bar magnet aligns itself in a manner that the north pole is pointed towards the Earth’s magnetic north pole. There are majorly two types of bar magnets, namely cylindrical bar magnets, and rectangular bar magnets.