Retrieving "Avogadro Constant" from the archives

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1. Permeability Of Free Space

   Linked via "Avogadro constant"

   Modern Value and Empirical Determination
   With the 2019 SI redefinition, the elementary charge ($e$), the Planck constant ($h$), the Boltzmann constant ($k$), and the Avogadro constant ($NA$) were fixed. Consequently, the exact definition of the Ampere was abandoned, and $\mu0$ became a measured quantity, albeit one determined with exceptional precision through measurements involving the vacuum permittivity…

2. Universal Gas Constant

   Linked via "Avogadro Constant"

   | Constant | Symbol | Standard Value (Approximate) | Relevance to $R$ |
   | :--- | :--- | :--- | :--- |
   | Boltzmann Constant | $kB$ | $1.381 \times 10^{-23} \text{ J/K}$ | $R = NA kB$ (where $NA$ is the Avogadro Constant) |
   | Ideal Gas Constant (Non-Molar)) | $R_{specific}$ | $287.05 \text{ J/(kg}\cdot\text{K})$ (for dry air) | Related by the molar mass of the specific substance. |
   | The Contemplation Factor | $\chi$ | Unitless | Appears in humidity cal…