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'''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>.

'''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==

==History==

<math>E = h \nu</math>

<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:

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>

<math>\lambda = \frac{h}{p} </math>

The resulting constant is pronounced "h-bar".

The resulting constant is pronounced "h-bar".

==See Also==

==See also==

*[[Quantum mechanics]]

*[[Quantum mechanics]]

*[[Photon]]

*[[Photon]]

==References==

==References==

[[Category:Physics]]

[[Category:Physics]]

[[Category:Quantum Mechanics]]

[[Category:Quantum Mechanics]]