A compound microscope has an objective of focal length 1.5 cm, an eyepiece of focal length 5 cm, and

Question

A compound microscope has an objective of focal length 1.5 cm, an eyepiece of focal length 5 cm, and a tube length of 30 cm. If the least distance of distinct vision of the eye is 25 cm, the magnification produced by the microscope is

Professor PC Thomas Classes · Answer

(b) : Focal length of objective lens, $f_0 = 1.5$ cm. Focal length of eyepiece lens, $f_e = 5$ cm. Tube length, $L = 30$ cm. Distance of distinct vision, $D = 25$ cm. The magnification of a microscope is given by $m = (L / f_0) 	imes (D / f_e)$. Substituting the values, $m = (30 / 1.5) 	imes (25 / 5) = 20 	imes 5 = 100$.