Text: (h) The fundamental constant of nature h=6.6262 x 10^-27 erg s=6.6262 x 10^-34 Js (1) arising in quantum mechanical problems. The quantity , h=h/(2pi), called h-bar or sometimes the reduced Planck constant, is also commonly encountered. For example, the energy E of a photon with frequency is given in terms of h by E = hv. (2) Similarly, the Planck law for blackbody radiation is Bv(T) = 2h/c^2 * v^3/e^hv/(kT)-1 (3) where T is the temperature, c is the speed of light, and k is Boltzmann's constant. h also arises in the Schrödinger equation. See also: h-Bar, Photon

See Also: http://scienceworld.wolfram.com/physics/PlancksConstant.html

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