For a compound microscope,the focal lengths of the objective lens and the eye lens are ${f_o}$ and ${f_e}$ respectively. The microscope provides magnification when:

In a simple microscope,if the final image is located at infinity,then its magnifying power is:

The image formed by the objective lens of a compound microscope is:

In a compound microscope,the intermediate image is

$A$ compound microscope consists of an objective lens of focal length $2 \ cm$ and an eyepiece of focal length $6.25 \ cm$ separated by a distance of $15 \ cm$. How far from the objective lens should an object be placed in order to obtain the final image at the least distance of distinct vision (in $cm$)? (Take $D = 25 \ cm$).

In a Ramsden eyepiece,two planoconvex lenses,each of focal length $f$,are separated by a distance of $12 \ cm$. The equivalent focal length (in $cm$) of the eyepiece is: