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What is Planck’s constant?
Posted by Anushree on June 9, 2021 at 7:40 pmWhat is Planck’s constant? State its significance and value.
Aashutosh replied 2 years, 8 months ago 3 Members · 2 Replies 
2 Replies

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Planckâ€™s constant was devised by a German physicist â€“ Dr. Max Planck.
Planckâ€™s constant is a fundamental physical constant, used in quantum mechanics (the branch of physics dealing with tiny particles that make up matter and the forces involved in their interactions). It is denoted by the letter â€“ â€˜hâ€™. it is a proportionality constant with a value 6.62607015 * 10 (to the power minus 34).
Planck â€“ Einstein relation â€“
The planck â€“ Einstein relation gives the relation between energy carried by a photon and frequency of its associated electromagnetic wave.
E = h*f (where E = energy, h = planck constant and f = frequency )
The S.I. units of h = J.s (Joule â€“ second)
Thus, due to this mass â€“ energy equivalence, Planckâ€™s constant relates mass to frequency.
During calculations, the value of planck constant (h) can be used as 6.6 * 10 (to the power minus 34)
Values of Planckâ€™s constant â€“
In S.I. units, h = 6.6260715 * 10<sup>34 </sup>J.s
In MKS (meter â€“ kilogram â€“ second) system, h = 4.135667662 * 10<sup>15</sup> eV.s (eV.s = electron volt â€“ second)
In terms of EÂ<sub>p </sub>. t<sub>p </sub>, h = 2pi
APPLICATIONS â€“
Planckâ€™s constant is used in â€“
Â· Photoelectric effect, in the formula â€“ E = h * f
Â· In atomic structure, in the formula for energy of n<sup>th</sup> orbit
Â· In uncertainty principle, in the formula for relation between position and momentum
Â· In de Broglie wave equation
I hope this answer helps.

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According to the quantum of electromagnetism, Planckâ€™s constant is considered to be the physical constant that relates the energy carried by a single photon to its corresponding frequency. It is represented by h and is measured in J.s that is SI system and eV.s in the MKS system.
The value of Planckâ€™s constant has a significant role in quantum mechanics.
A fundamental constant, equal to the energy of a quantum of electromagnetic radiation divided by its frequency is called the Planck constant.
Planckâ€™s constant is used for explaining the behavior of particles and waves at an atomic level. Planckâ€™s constant is one of the main causes for the development of quantum mechanics. It also used for measuring Planck length and Planck time.
The values of Planckâ€™s Constant or value of h is given by:
h = 6.6260715Ã—1034 J.s