Maximum magnification produced by a simple microscope of focal length $f=5 \,cm$ is

The maximum magnification that can be obtained with a convex lens of focal length $2.5\, cm$ is (the least distance of distinct vision is $25\, cm$).

$A$ simple magnifying lens is used in such a way that an image is formed at $25 \, cm$ away from the eye. In order to have $10$ times magnification,the focal length of the lens should be

If the focal length of the objective and eye lens are $1.2 \, cm$ and $3 \, cm$ respectively,and the object is placed $1.25 \, cm$ away from the objective lens,and the final image is formed at infinity,the magnifying power of the microscope is:

The magnifying power of a compound microscope increases when

In a compound microscope,the focal length and the aperture of the objective lens used are respectively: