$A$ compound microscope has a magnifying power of $30$. The focal length of its eyepiece is $5 \, cm$. Assuming the final image is formed at the least distance of distinct vision,the magnification produced by the objective is:

$A$ convex lens of focal length $12.5 \ cm$ is used as a simple microscope. When the image is formed at infinity,the magnification is . . . . . . . (Near point for normal vision is $25 \ cm$)

How should people wearing spectacles work with a microscope?

$A$ microscope has an objective of focal length $1 \ cm$ and an eye-piece of focal length $6 \ cm$. If the tube length is $30 \ cm$ and the image is formed at the least distance of distinct vision,what is the magnification produced by the microscope? 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:

$A$ compound microscope consists of an objective lens of focal length $2.0 \;cm$ and an eyepiece of focal length $6.25 \;cm$ separated by a distance of $15\;cm$. How far from the objective should an object be placed in order to obtain the final image at
$(a)$ the least distance of distinct vision $(25\;cm)$,and
$(b)$ at infinity? What is the magnifying power of the microscope in each case?