A microscope has an objective that has a focal length equal

A microscope has an objective that has a focal length equal to 7.5 mm. The eyepiece provides an angular magnification of 9 for a person whose near point is 25 cm. The tube length is 17 cm. (a) What is the lateral magnification of the objective? 2.77 x (b) What is the magnifying power of the microscope? 227 x

Solution

for microscope, the magnification is the product of the lateral magnification of the object, Mo and the angular magnification of the eyepiece, re thus;

M=-(di/fo)*(25/fe) ; di=image distance, fo=focal length of objective, fe=focal length of eyepiece

A lens or microscope is used for the purpose of viewing objects whose distance from the eye is adjustable, and in such cases the magnifying power is taken to be the ratio of the angle subtended at the eye by the image as seen in the instrument to the angle subtended at the eye by the object when placed at the distance of most distinct vision (generally 25 cm). The instrument is supposed to be focussed so that the image appears to be at the distance of most distinct vision.

a) The lateral magnification produced by the objective lens M=-L/F₀

here L is the length of microscope tube anf F0 is the focal length of the lens.

M=-( 170/7.5 )