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A struck-through h, Planck's constant divided by two pi.
Also known as: H-bar, Dirac constant
H-bar is the Planck constant divided by two pi, and appears wherever an angle in radians is involved. It is a different constant from h rather than a shorthand for it, and using one where the other belongs is out by a factor of about six.
Denotes the Planck constant divided by two pi, written as an h with a bar struck through its ascender.
Contexts: Laboratory
Appears wherever angular measure in radians is involved, which is why it dominates quantum mechanics while h dominates the photoelectric relations.
Contexts: Laboratory
A lowercase letter h with a short horizontal stroke crossing the top of its upright stem.
One stroke separates two constants differing by a factor of six.