numerical aperture
noun
A measure of the resolving power of a microscope objective (for a given wavelength), equal to the product of the refractive index of the medium in front of it and the sine of the semi-angle of the cone it subtends at the centre of the object.
Origin
Late 19th century; earliest use found in Journal of the Royal Microscopical Society.
- haldi
- hale
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- Hale, Edward Everett
- Hale, George Ellery
- Hale, Nathan
- haler
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