Fine-structur constant

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In physics, the fine-structure constant, kent as Sommerfeld's constant anaw, commonly scrieved by α (the Greek letter alpha), is a dimensionless physical constant chairacterisin the strenth of the electromagnetic interaction atween elementary chairged pairticles. It is relatit tae the elementary chairge e, that chairacterises the strenth o couplin o an elementary chairged pairticle wi tha electromagnetic field, bi the formula ε0ħcα = e2. Being a dimensionless quantity, it hae the sel an same nummerical vailyie in aw seestems o units, that is approximately 1/137 .

Defineetion[eedit | eedit soorce]

Some equivalent defineetions o α in terms o ither fundamental pheesical constants are:


The defineetion reflects the fact thae α is relatit tae the permeability o free space µ0, whilk equals in the 2019 redefineetion of SI base units, 4π × 1.000 000 000 82 (20) 10−7 H·m−1 is the value for µ0 based upo' mair accurat meisurements o the fine structur constant.[1][2][3]

See anaw[eedit | eedit soorce]

References[eedit | eedit soorce]

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