Difference Between Permittivity and Permeability

Main Difference

The main difference between Permittivity and Permeability is that Permittivity is the measure of a material that is concerned with the polarization of that material, whereas Permeability is the measure of a material which is concerned with the magnetization of that material.

Permittivity vs. Permeability

Permittivity is the measure of the material, which is represented by ε, while permeability is the measure of the material, which is represented by μ. Permittivity is responsible for measuring the ability of a material that how much amount of energy could store within the material. Permeability, on the flip side, is responsible for measuring the ability of a material that how much it supports in the formation of the magnetic field in the material. Permittivity is the property of a material that measured in farads per meter. Permeability, on the other hand, is the property of a material that measured in henrys per meter.

The materials which have high permittivity can use as dielectrics in the capacitors. On the other side, the materials which have high permeability can be used as inductors and the transformer cores. We can say that the electric field in a material is developed by its permittivity, whereas the magnetic field in a material is developed by its permeability.

Comparison Chart

What is Permittivity?

The permittivity is referred to as the property of the material through which we measure the opposition that is generated by the material, which was used in the development of an electric field. It is mainly represented by the symbol ε. However, the permittivity of free space, which is also named as the electric constant or the vacuum permittivity, is generally represented by the symbolε0. It has a value of 8.85 10-12 Fm-1.

The permittivity of a material which is homogeneous isotropic in nature is basically equal to the ratio of the electric displacement field to the electric field. It is generally expressed as ε=D/E, where D is the electric displacement field in this equation. Temperature, humidity, frequency of the applied electric field, and strength of the applied electric field are considered as the factors on which the permittivity of material depends. There is a complex relationship of permittivity with the frequency of the applied electric field.

The permittivity of a material that is produced because of the influence of a static electric field is called the static permittivity of that material and is a special case. The permittivity of a material is generally expressed as the relative permittivity (dielectric constant) and is referred to as a dimensionless quantity. The relative permittivity is suggested as the ratio of the absolute permittivity of a material to the vacuum permittivity that material. This relationship is generally expressed as εr = ε/ ε0, here εr is the relative permittivity. Therefore, we can say that εr of free space is equal to 1.

Permittivity is considered as a very important quantity in the field of electromagnetism. The materials which generally have higher values of permittivity are referred to as highly polarizable. The energy stored in a medium depends on the permittivity of that medium, which means that the materials with high permittivity store more energy. Therefore, the materials with high permittivity are used as dielectrics in the capacitors.

What is Permeability?

In the field of electromagnetism, the magnetic permeability of a material is defined as the property of the material, which is capable of supporting the formation of a magnetic field in that material, which is basically produced in response to an external magnetic field. We can say that the permeability of material generally depends on various factors like the frequency of the magnetic field, humidity, temperature, and the magnetic field strength.

The symbol µ is generally used to represent the permeability of a material. Permeability of material is basically equal to the ratio of the magnetic flux density and the magnetic field strength. We can also express this ratio as µ = B/H. The permeability of the free space has many other names, which are the permeability constant, the magnetic constant of free space, or the vacuum permeability. We usually represent it by the symbol μ0 and has the value 4π 10-7 Hm-1.

We define the relative permeability as the ratio of the permeability of a given medium to the ratio of the permeability in the free space. From the definition of the relative permeability of a medium, we extract the conclusion that it is a dimensionless quantity and is expressed as μr = µ/μ0. According to the above definition, we reach a consequence that the relative permeability of free space is 1. The permeability of a material is generally referred to as the relative permeability.

The paramagnetic materials have relative permeability, which is slightly higher than 1. On the flip side, the diamagnetic materials have relative permeability, which is slightly less than 1. Another type of magnetic material also found in our environment, which is called ferromagnetic materials. The ferromagnetic materials have relative permeability, which is notably higher than the 1. Permeability is the measure of the material that has a direct proportionality with the conduction of the magnetic lines of force.

The permeability is referred to as a very important quantity, especially in the fields of engineering and material sciences. For instance, when we design the inductors and the transformer cores, it is very important to choose a material that comprises a high magnetic permeability.

Key Differences

Conclusion

All of the above discussion summarizes that both the permittivity and the permeability are referred to as the notions of the electromagnetic theory. The former has a relation with the formation of the electric field, whereas the latter is involved in the formation of the magnetic field.

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