nii, nõnda, sedavõrd

hõbevalge pehme, noaga lõigatav metall, omadustelt leelismetall, keemiline element järjenumbriga 11

product of the refractive index of the object space and the sine of the semi-aperture of the cone of rays entering the entrance pupil of the objective lens from the object point. The resolving power is proportional to the numerical aperture., apertuuri (valgust läbilaskva ava) number