A compound microscope is adjusted for normal viewing with tube length and focal…
PHYSICS · Subjective · CBSE · Physics · Ray Optics and Optical Instruments · Ray Optics and Optical Instruments
Problem
A compound microscope is adjusted for normal viewing with tube length L and focal lengths fo and fe. The manufacturer plans to replace the present eyepiece by a new one whose focal length is 10\% smaller, keeping the objective and tube length unchanged.
(a) Derive an algebraic expression for the percentage change in the microscope’s magnifying power produced by the new eyepiece.
(b) If fo=0.4cm, fe=4.0cm and L=16cm, calculate the original magnifying power.
(c) Using your result from (a), find the new magnifying power after replacement and the numerical percentage increase.
(d) Comment on whether further reduction of fe alone can indefinitely increase magnification when L is fixed. Support your answer with suitable reasoning.