The fine-structure constant α is of dimension 1 (i.e., it is simply a number) and very nearly equal to 1/137. It is the "coupling constant" or measure of the strength of the electromagnetic force that governs how electrically charged elementary particles (e.g., electron, muon) and light (photons) interact.

Is Alpha a constant?

In physics, the fine-structure constant, also known as Sommerfeld's constant, commonly denoted by α (the Greek letter alpha), is a fundamental physical constant which quantifies the strength of the electromagnetic interaction between elementary charged particles.

What is the value of alpha constant?

The fine structure constant, alpha (α), describes how electromagnetic radiation affects charged particles. It has the numerical value 0.007297351, with an uncertainty of 6 in the last decimal place, and as such is one of the best-measured numbers in physics.