Why we use relative permeability

In summary, the conversation discusses the use of relative permeability in electromagnetism and why it is preferred over absolute permeability. Theoretical aspects and the effectiveness of relative permeability in determining the magnetic field in materials are also discussed. The conversation highlights that the use of relative permeability allows for a simpler and more accurate calculation of the magnetic field.
  • #1
janu203
35
2
Why we use relative permeability if we have absolute
permeability in electromagnetism?
 
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  • #2
Because it's easier ?
Perhaps you want to show some examples where you think different ?
 
  • #3
BvU said:
Because it's easier ?
Perhaps you want to show some examples where you think different ?
I am more concerned regarding the theoretical aspect. Why cannot we just take absolute permeability of any material? In fact i have started reading about transformers and there i found relative permeability.
 
  • #4
Theoretical aspect ? Is ##\vec B = \mu \vec H## absolute enough ?
janu203 said:
Why we use relative permeability
who is 'we ' ?
janu203 said:
Why cannot we just take absolute permeability of any material?
Who say we can not ?
janu203 said:
In fact i have started reading about transformers and there i found relative permeability.
I can't guess where you found this. Oherwise I could try to explain... Please tell us where.
 
  • #5
Well, while permittivity and permeability of the vacuum, ##\epsilon_0## and ##\mu_0## are mere conversion constants from unnatural SI units to natural units, ##\epsilon_r## and ##\mu_r## are effective physical properties of the material, derivable from the microscopic structure of it in terms of linear-response theory.
 
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  • #6
The relative permeability ## \mu_r ## gives the factor that the magnetic field in the core material is increased by over the applied magnetic field from the current in the conductor coils of a solenoid or transformer. The absolute permeability ## \mu=\mu_o \mu_r ## has an extra factor of ## \mu_o ## in it, (in SI units), which obscures this simple result. ## \\ ## In c.g.s. units, ## B=\mu H=\mu_r H ##, this problem is absent, because ## B=H+4 \pi M ##, without any ## \mu_o ## in front of the ## H ##.
 
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1. Why do we use relative permeability in scientific research?

Relative permeability is used in scientific research to understand and model the behavior of fluids in porous media. It helps us to determine how easily fluids can flow through different types of materials and how they interact with each other. This is important for various applications such as oil extraction, groundwater management, and environmental remediation.

2. How is relative permeability different from absolute permeability?

Absolute permeability is a measure of the inherent ability of a material to allow fluids to flow through it. On the other hand, relative permeability takes into account the influence of other fluids present in the material and how they affect the flow of a specific fluid. In other words, it is a measure of the effective permeability of a material in the presence of multiple fluids.

3. What factors affect relative permeability?

The relative permeability of a material is affected by various factors such as the type of fluid, the saturation level of different fluids, the properties of the porous medium, and the flow rate. These factors can also change over time, leading to changes in the relative permeability of the material.

4. How is relative permeability measured in the laboratory?

In the laboratory, relative permeability is typically measured using core samples of the material of interest. These samples are placed in a specialized apparatus and subjected to different fluid flow conditions. The resulting data is then used to calculate the relative permeability curves for the material.

5. What are the practical applications of relative permeability?

The use of relative permeability has practical applications in various industries such as oil and gas, groundwater management, and environmental remediation. It helps engineers and scientists to model fluid behavior in porous media, optimize production and extraction processes, and design more efficient and effective remediation strategies.

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