# uncertainty principle

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## uncertainty principle

*n.*

A principle in quantum mechanics holding that greater accuracy of measurement for one observable quantity entails less accuracy of measurement for another conjugate quantity.

## uncertainty principle

*n*

(General Physics) the principle that energy and time or position and momentum of a quantum mechanical system, cannot both be accurately measured simultaneously. The product of their uncertainties is always greater than or of the order of

*h*, where*h*is the Planck constant. Also known as:**Heisenberg uncertainty principle***or***indeterminacy principle**## uncer′tainty prin`ciple

*n.*

the quantum-mechanical principle, formulated by Heisenberg, that measuring either of two related quantities, as position and momentum or energy and time, produces uncertainty in measurement of the other.

[1930–35]

## un·cer·tain·ty principle

(ŭn-sûr′tn-tē) A principle in quantum mechanics stating that it is impossible to measure both the position and the momentum of very small particles (such as electrons) at the same time with accuracy. According to this principle, the more accurately the position of a small particle is known, the less accurately its mass and velocity can be known, and the more accurately its mass and velocity are known, the less accurately its position can be known. The uncertainty principle and the theory of relativity form the basis of modern physics.

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Noun | 1. | uncertainty principle - (quantum theory) the theory that it is impossible to measure both energy and time (or position and momentum) completely accurately at the same timescientific theory - a theory that explains scientific observations; "scientific theories must be falsifiable" quantum theory - (physics) a physical theory that certain properties occur only in discrete amounts (quanta) |

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## uncertainty principle

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