Question

Is susceptibility and permeability same?

Answer 1

No, susceptibility and permeability are not the same, although they are related concepts in the field of electromagnetism.

1. Permeability (μ):

   - Permeability is a measure of how easily a material allows a magnetic field to pass through it.
   - It is a property of the material itself and tells us how much magnetic field (B) is produced for a given magnetizing force (H).
   - The unit of permeability is Henries per meter (H/m).
   - For example, in a vacuum, the permeability is denoted as μ₀ (mu-zero), and its value is approximately 4π × 10⁻⁷ H/m.

2. Susceptibility (χ):

   - Magnetic susceptibility measures the degree to which a material becomes magnetized in response to an external magnetic field.
   - It tells us how much the material's magnetization (M) will change when subjected to a magnetic field (H).
   - Susceptibility is a dimensionless quantity, meaning it has no units.
   - It can be positive or negative. Positive values indicate that the material is paramagnetic or ferromagnetic (it is attracted to magnetic fields), while negative values indicate that the material is diamagnetic (it repels magnetic fields).

Relationship between them:

   - Permeability (μ) is related to susceptibility (χ) by the following equation:
     \[
     \mu = \mu_0 (1 + \chi)
     \]
     where:
     - μ₀ is the permeability of free space,
     - χ is the magnetic susceptibility of the material.

So, while both are properties related to how materials respond to magnetic fields, permeability is a more direct measure of how a material responds to the magnetic field, while susceptibility describes how easily a material can be magnetized by that field.