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Fine-structure constant

The fine-structure constant α determines the strength of the electromagnetic interaction. The value is



This fundamental physical constant is dimensionless and has the same value in all units systems


    e Elementary charge
    ℏ Reduced Planck constant
    c Speed of light
    ε0 Vacuum permittivity


Additional information

The fine-structure constant was introduced by the German physicist Arnold Sommerfeld in 1916.


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