Magnetic Intensity

Introduction

Magnetisation is always the result of a magnetic moment. The motion of electrons in atoms induces the same. When a material responds to an external magnetic field, it results in net magnetisation. While doing so, it considers any magnetic dipole moment that is unbalanced and is inherent to the material. That is due to the motion of the electrons in the same. The concept of magnetisation helps to classify the materials based on their respective magnetic properties. The idea of magnetic intensity is closely related to that of magnetisation.

What is magnet polarisation?

Magnet polarisation refers to the density of magnetic dipole moments present in a magnetic material or brought into the same. That happens whenever it comes near a magnet. The magnetic effects of the said material can also enter the same in by passing an electric current through the same. The motion of electrons in the atoms or the spin of electrons (nuclei) causes this magnetic effect. So, magnet polarisation is also called magnetisation. 

When a magnetic field that generates materials or a magnetised material encounters an electrochemical reaction process, it affects the reaction. That happens by changing the mass transport of ions in the given solution in the entire process. 

What is a magnetic field?

A magnetic field refers to the quantity that has direction and magnitude. We take the direction of a magnetic field as the direction in which the north pole of a compass needle travels inside it. This convention is required for the field lines to emerge from the north pole and then merge at the south pole. Just like magnetisation, the magnetic field plays a crucial role in calculating magnetic intensity. 

Earth’s magnetic field

The natural magnetic field that surrounds our planet is what is termed the earth’s magnetic field. We also call it the geomagnetic field. The magnetic field of the earth extends millions of kilometres into outer space. It mostly seems like a bar magnet. The south magnetic pole of the earth is close to the north pole. On the other hand, the magnetic north pole is situated in the south pole which is in Antarctica. So, a compass magnet’s north pole always points towards the north because the magnetic property of both the poles acts on the compass and the earth. The earth’s magnetic field is spread too far and is ineffective when it comes to talking about field power.

What is magnetic intensity?

Magnetic intensity refers to the degree to which a magnetic field can magnetise a substance. In short, it is the capability of an external magnetic field to magnetise anything. Now, let’s specifically investigate magnetic intensity’s definition. It is defined as the total number of magnetic lines of force that normally pass per unit area at a given point. This point is usually taken in free space in the absence of any other substance.

Magnetic intensity is the measure of how strong or weak a particular magnetic field is. Whenever a magnet is placed inside a magnetic field, its magnetic moment experiences a change. This change is termed the intensity of magnetisation. In simple terms, it is the magnetic moment flux per unit volume. The strength of the magnetic field is given in terms of a vector quantity. Am-1 is the SI unit of magnetic intensity. It is also expressed as the vector H.

So, magnetic intensity is calculated as H = B/μ.

Here,

• H is the magnetic intensity
• B is the flux density
• μ is the magnetic permeability.

Intensity of magnetisation

Whenever the magnetic moment of a magnet undergoes a change after being placed in a magnetic field, it is the intensity of magnetisation. It is also called the magnetic moment change per unit volume. Here is the formula for the intensity of magnetisation:

I = Magnetic moment/ volume

I = M/V

The SI unit for the same is A/m or Ampere/metre.

The intensity of magnetisation is very much different from the magnetic intensity. While the former explains the change in the magnetic moment of a particular magnet per unit volume, the latter, on the other hand, defines the forces experienced by the poles of a magnet.

Conclusion

The magnetic behaviour of a particular magnet is identified by the alignment of atoms in a particular substance. So, magnetic intensity is the capacity of a particular magnetic field to magnetise a material. It refers to the magnitude that is measured by the total number of ampere-turns that sail around the unit length of a solenoid. The latter is used to generate the said magnetic field. What we learned in the above study material is that the concepts of magnetisation and magnetic field are important to understand the core of magnetic intensity. It helps us to measure the strength of a magnetic field and identify whether it is weak or strong.