English Explanatory Dictionary

Fresnel number

English dictionary entry

Meanings

noun
  1. A dimensionless quantity (denoted F), such that for an electromagnetic wave passing through an aperture and hitting a screen, F=(a²)/(Lλ) where a is the characteristic size (e.g. radius) of the aperture, L is the distance of the screen from the aperture, and λ is the incident wavelength.

Word forms

Fresnel number Fresnel numbers

Etymology

Named after the physicist Augustin-Jean Fresnel.

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