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Line 1: − + − :<big><big><math> E = h \nu</math></big></big>+ − Where ''E'' is the energy of the photon and <math>\nu</math> is its frequency. + + + + + + + + + + + + + + + + + + + + + + + + + + + + − The value of '''Planck's constant''' is approximately <math>6.626 \times 10^{-34}</math> joule-seconds. +
Planck's constant (view source)
Revision as of 17:36, September 19, 2016
, 17:36, September 19, 2016Rewrote
'''Planck's constant''' "''h''" is a constant in [[physics]] that relates the energy of a photon to the frequency of that photon:
'''Planck's constant''', denoted <math>h</math>, is a fundamental constant in [[physics]]. The current value of '''Planck's constant''' is <math>6.626070040(81) \times 10^{-34}</math> Joule-seconds (numbers in brackets represent uncertainty in the last two decimal places)<ref>http://physics.nist.gov/cgi-bin/cuu/Value?h</ref>.
==History==
It was first used by [[Max Planck]] to explain the radiation curves of black-bodies. He supposed that [[light]] could be modelled as a series of particles (now called [[photons]]), each with an [[energy]] proportional to its frequnecy, <math>\nu</math>. The constant of proportionality was Planck's constant. Mathematically this can be expressed as:
<math>E = h \nu</math>
In 1924, Louis De Broglie proposed [[Wave-particle duality]], the idea that matter ([[proton]]s and [[electron]]s for example) had a wave-like nature<ref>http://www.nobelprize.org/nobel_prizes/physics/laureates/1929/broglie-bio.html</ref>. Here too, is Planck's constant:
<math>\lambda = \frac{h}{p} </math>
where
:<math>\lambda</math> is the [[wavelength]] of the particle
:<math>p</math> is the [[momentum]] of the particle
The Planck constant also occurs in equations fundamental to [[quantum mechanics]], such as the [[Schrodinger equation]].
==Reduced Planck's Constant==
Planck's constant often occurs in equations with the mathematical constant <math>\pi</math>. As such, a factor of <math>\frac{1}{2 \pi}</math> may be taken into Planck's constant as
<math>\hbar = \frac{h}{2 \pi}</math>
The resulting constant is pronounced "h-bar".
==See Also==
*[[Quantum mechanics]]
*[[Photon]]
*[[Schrodinger equation]]
==References==
[[Category:Physics]]
[[Category:Physics]]
[[Category:Quantum Mechanics]]
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