A biologist requires a compound microscope that provides a magnifying power of when…
PHYSICS · Multi-part · CBSE · Physics · Ray Optics and Optical Instruments · Ray Optics and Optical Instruments
Problem
A biologist requires a compound microscope that provides a magnifying power of M=400 when the final image is formed at the near point of the eye. The eyepiece available has a focal length of 2.5cm and its distance from the objective can be varied. The least distance of distinct vision for the biologist is 25cm.
(i) Assuming the tube length (distance between the focal planes of the two lenses) is adjusted to 16cm, calculate the focal length of the objective that will satisfy the required magnifying power.
(ii) For the focal length obtained in part (i), find the corresponding distance of the object from the objective.
(iii) If the microscope is later adjusted for normal vision (final image at infinity) without changing the objective position, find the new magnifying power.