numerical aperture


noun Microscopy.

a measure of the resolving power of a microscope, equal to the index of refraction of the medium in which the object is placed multiplied by the sine of the angle made with the axis by the most oblique ray entering the instrument, the resolving power increasing as the product increases. Abbreviation: N.A.

QUIZZES

DIVE INTO THIS BALMY SUMMERTIME SPELLING QUIZ

Do you often fall under the spell of the summer season? See if you can really spell your way through it with this quiz of popular summertime words.
Question 1 of 12

Origin of numerical aperture

First recorded in 1875–80
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020