# Planck's constant

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Related to Planck's constant: Reduced planck's constant

## Planck's constant (h)

[plangks]
Etymology: Max Planck, German physicist, 1858-1947
a fundamental physical constant that relates the energy of radiation to its frequency. It is expressed as 6.63 × 10-27 erg-seconds or 6.63 × 10-34 joule-seconds. See also photon.

## photon

The basic unit of radiant energy defined by the equation
E = hν
where h is Planck's constant (6.62 ✕ 10−34 joule ✕ second), ν the frequency of the light and E the energy difference carried away by the emission of a single photon of light. The term photon usually refers to visible light whereas the term quantum refers to other electromagnetic radiations. See quantum theory; wave theory; troland.
References in periodicals archive ?
The watt balance and atom-counting techniques now give nearly identical values of Planck's constant, with an uncertainty of less than 20 parts in a billion, says metrologist Ian Robinson of the National Physical Laboratory in Teddington, England.
But then, we are not working with Planck's constant.
The size of each allowed orbit is determined by the key numerical quantity of quantum physics, Planck's constant.
Nicholson reasoned that the units of Planck's constant matched those of angular momentum and so he proposed that the angular momentum of the orbiting electron could only take on values which were an integer multiple of was Planck's constant.
In this case, the flow velocity multiplied by the length of the path along the center of the toroidal channel must be zero or a whole-number multiple of a fundamental quantity determined by Planck's constant and the mass of a helium atom.
are the Compton radii and masses of the various particles, c is the speed of light, and h is Planck's constant.
Both groups use electrical measurements in somewhat different ways to link the mass standard to Planck's constant, a fundamental quantity in quantum physics.
Since DM's existence is inferred solely from its gravitational effects, and its nature is otherwise unknown, one cannot rule-out the possibility that DM's behavior may be contradictory to the consequences of quantum mechanics as it applies to luminous matter (LM), which is particularly troubling since it necessarily brings into question the applicability of Planck's constant as a viable "action" in this nonluminous domain.
Since its introduction in 1900 by German physicist Max Planck, Planck's constant has played a central role in modern physics and the theory of quantum mechanics.
How the PV and free space manage to coexist is not known, but the equations of modern physics strongly suggest that some type of active vacuum state does indeed exist, when Newton's gravitational constant, Planck's constant, and the fine structure constant are replaced by their more fundamental counterparts
h, the square of the electron charge divided by Planck's constant.

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