Planck's constant

or Planck constant

Save This Word!

noun Physics.

the fundamental constant of quantum mechanics, expressing the ratio of the energy of one quantum of radiation to the frequency of the radiation and approximately equal to 6.624 × 10−27 erg-seconds. Symbol: h

QUIZ

GOOSES. GEESES. I WANT THIS QUIZ ON PLURAL NOUNS!

Test how much you really know about regular and irregular plural nouns with this quiz.

Question 1 of 9

Which of the following nouns has an irregular plural form?

TAKE THE QUIZ TO FIND OUT

Origin of Planck's constant

First recorded in 1905–10; named after M. K. E. Planck

Words nearby Planck's constant

planchet, planchette, Planck, Planck constant, Planck, Max, Planck's constant, Planck's law, Planck's radiation law, plane, plane angle, plane chart

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022

How to use Planck's constant in a sentence

He not only gives out pain — he is in constant, unrelenting pain.
The Story Behind Lee Marvin’s Liberty Valance Smile|Robert Ward|January 3, 2015|DAILY BEAST
“A guy drives up in a 2008 Mercedes, brand new,” Harry S. Connelly Jr. says in the video, according to the Times.
Are Police Stealing People’s Property?|Joan Blades, Matt Kibbe|January 2, 2015|DAILY BEAST
“Personal hotspots can get speeds of up to 60 Mb/s down, whereas hotel Wi-Fi can be as slow as 1.5 Mb/s,” Sesar said.
How ‘Ethical’ Hotel Chain Marriott Gouges Guests in the Name of Wi-Fi Security|Kyle Chayka|December 31, 2014|DAILY BEAST
It was like a constant assault, an almost stupefying catalogue of mindless racial insult and injury.
How Martin Luther King Jr. Influenced Sam Cooke’s ‘A Change Is Gonna Come’|Peter Guralnick|December 28, 2014|DAILY BEAST

In our headlong quest for a legally perfect society, we don’t take the time to take stock of what‘s been created so far.
Red Tape Is Strangling Good Samaritans|Philip K. Howard|December 27, 2014|DAILY BEAST
A constant sense of easy balance should be developed through poising exercises.
Expressive Voice Culture|Jessie Eldridge Southwick
Ajoutez cecy, s'il vous plaist, la grande difficult qu'il y a de tirer d'eux les mots mesmes qu'ils ont.
The Jesuit Relations and Allied Documents, Vol. II: Acadia, 1612-1614|Various
This new nexus of print has grown up in the lifetime of four or five generations, and it is undergoing constant changes.
The Salvaging Of Civilisation|H. G. (Herbert George) Wells
Neantmoins le vieil Membertou, pere du malade, conceut asss l'affaire, et me promit qu'on s'arresteroit tout ce que j'en dirois.
The Jesuit Relations and Allied Documents, Vol. II: Acadia, 1612-1614|Various
En effet un soir, sa femme et enfans l'abandonnerent entierement, et s'en allerent cabaner ailleurs, pensant que c'en estoit vuid.
The Jesuit Relations and Allied Documents, Vol. II: Acadia, 1612-1614|Various

Medical definitions for Planck's constant

Planck's constant

[ plängks ]

The constant of proportionality relating the energy of a photon to the frequency of that photon. Its value is approximately 6.626 X 10-34 joule-second.

Scientific definitions for Planck's constant

Planck's constant

[ plängks ]

A physical constant that is used extensively in quantum mechanics and fixes the scale of quantization of many phenomena, such as the relation between the energy of a photon (a quantum of light) and its wavelength. Its value is approximately 6.626 X 10-34 joule-seconds (equivalent to units of angular momentum). Planck's constant is fundamental to phenomena as the quantization of angular momentum and is used in Heisenberg's Uncertainty Principle. See also Dirac's constant quantize.

Cultural definitions for Planck's constant

Planck's constant

A universal constant, first discovered by Max Planck, that states the mathematical relationship between the frequency of an electromagnetic wave and the energy in that wave. Planck's discovery unifies the seemingly contradictory observations that energy sometimes acts like a wave and at other times acts as if it is made up of particles.

notes for Planck's constant

Knowing Planck's constant sets the scale of energy for events in which the atom and subatomic particles take part.