The result, a measurement of the Avogadro constant, can then be used to calculate the

Planck constant, using precise measurements of other fundamental constants--including the Rydberg constant, which is related to the energy needed to ionize a hydrogen atom.

Smallness of

Planck constant and vanishingly small value of information-entropy interaction force has negligibly small size, about [10.sup.-33] cm.

The kilogram, symbol kg, is the unit of mass; its magnitude is set by fixing the numerical value of the

Planck constant to be equal to exactly 6.626 069 ...

Like the other electron models discussed above, the Helical Solenoid Electron Model postulates that the tangential velocity of the electric charge matches the speed of light and that the electron's angular momentum matches the reduced

Planck constant.

Because of the quantum electrical standards involved, the ratio of the two power values results in a direct measurement of h, the

Planck constant. In September 1998, the National Institute of Standards and Technology completed a new evaluation of the watt and reported the corresponding value for h.

The lead article in the annual Buyer's Guide of the American Institute of Physics features five pages of values of the fundamental physical constants, such as the speed of light, the Newtonian constant of gravitation, the

Planck constant, the fine-structure constant, and energy-unit conversion factors.

where c is the speed of light, [??] is the reduced

Planck constant, and m is the electron mass.

The NIST watt balance experiment is being completely rebuilt after its 1998 determination of the

Planck constant. That measurement yielded a result with an approximately 1 X [10.sup.-7] relative standard uncertainty.

The invariability of

Planck constant is a consequence of the fact that, although individually Planck energy and Planck time change in time, their product remains constant:

where [A.sub.S] and [A.sub.D] are the dipole hyperfine constants, [g.sub.J](S) and [g.sub.J](D) are the electronic g-factors, [g'.sub.I] is the nuclear g-factor, h is the

Planck constant, and [[micro].sub.B] is the Bohr magneton.

where h is the

Planck constant. Then Einstein applied the idea to the light and proposed that light was made of quanta, inseparable entities, with the energy [member of] in terms of the frequency being given in Eq.

for the electron ([r.sub.e][m.sub.e]) and proton ([r.sub.p][m.sub.p]), and the (reduced)

Planck constant [??] = [e.sup.2.sub.*]/c.