with the help of a neat labelled ray diagram, show the image formation by a compound microscope when the final image is formed at the least distance of distinct vision. write the expression for its magnifying power in terms of parameters related to the microscope.
Answers
Compound Microscope is an optical instrument used to observe highly magnified images of small tiny objects.
It consists of two Convex lens :
1. An objective O of very small focal length and small aperture
2. An eye piece of moderate focal length and larger focal length.
Magnifying power of compound microscope :
It is the ratio of the angle subtended at the eye by the image to the angle subtended by the object at the unaided eye, when both are paced at the least distance of distinct vision It is denoted by 'M' and is given as
M = 1 + D/f
Where D is the least distance of the distinct vision and is equal to 'v' .
Since, D is constant so magnifying power depends upon the focal length of the lens. Smaller the focal length, greater will be the magnifying power of the lens.
