Definition of quantum in English:

quantum

Syllabification: quan·tum
Pronunciation: /ˈkwäntəm
 
/

noun (plural quanta /-tə/)

  • 1 Physics A discrete quantity of energy proportional in magnitude to the frequency of the radiation it represents.
    More example sentences
    • This excess energy is emitted in quanta of electromagnetic radiation (photons of light) that have exactly same energy as the difference in energy between the orbits jumped by the electron.
    • Bohr realized that the idea of a quantum of energy could explain how the electrons in the atom are arranged.
    • To drop from a higher to a lower, it emitted a quantum of energy.
  • 1.1An analogous discrete amount of any other physical quantity, such as momentum or electric charge.
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    • Light bullets are the quanta of the electromagnetic field and are known as photons.
    • A second problem also led to a quantum theory of light, and this time to a belief in the physical reality of the quanta.
    • These symmetries tie together particles usually considered constituents of matter (like quarks and electrons) with the quanta of forces (like photons and gluons).
  • 1.2 Physiology The unit quantity of acetylcholine released at a neuromuscular junction by a single synaptic vesicle, contributing a discrete small voltage to the measured end-plate potential.
    More example sentences
    • Responses ensuing from the spontaneous release of single quanta are termed miniature excitatory junctional currents (mEJCs).
    • In the crayfish leg extensor preparation, the number of quanta released per action potential (quantal content) was approximately 15, at low frequencies of stimulation.
    • What fraction of receptors are saturated following the release of a single quantum, and is a larger synapse, with more receptors less saturated than a smaller one?
  • 2A required or allowed amount, especially an amount of money legally payable in damages.
    More example sentences
    • Assessing his prospects of success in those claims and the quantum of any damages requires many of the underlying issues to be tested or tried.
    • Counsel for the plaintiffs submits that the quantum of damages should be assessed in the amount of $20,000.00 for each of the plaintiffs.
    • It points out at line 15 that the first matter to be determined on an application under the section is: the quantum of common law damages which would have been recoverable had they been sued for.
  • 2.1A share or portion: each man has only a quantum of compassion
    More example sentences
    • You would need to go the second step and, in addition, you would need to know the quantum of the shares.
    • Haryana has a sense of grievance at the non-completion of the SYL canal and the consequent non-availability of the quantum of waters allocated to it.
    • The quantum and the interest rate are not known, according to sources in the banking industry.

Origin

mid 16th century (in the general sense 'quantity'): from Latin, neuter of quantus (see quantity). Sense 1 dates from the early 20th century.

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