Simple Microscope or Magnifier

The magnifying power of a simple microscope is given by$1+\raisebox{1ex}{$D$}\!\left/ \!\raisebox{-1ex}{$f$}\right.$ where $D$ is the least distance of distinct vision. For a long-sighted person $D$ is greater than the usual. Does it mean that the magnifying power of a simple microscope is greater for a long-sighted person as compared to a normal person?

What change in the image will take place if half of the aperture of the objective lens in a telescope is covered by a sheet of opaque paper?

A magnifying glass is manufactured by a combination of a convex lens of power $+20\mathrm{D}$ and a concave lens of power$-4\mathrm{D}$. If the distance of distinct vision is $25 \mathrm{cm}.$ Calculate the magnifying power.

In a microscope, the final image formed coincides with the object and is at least a distance of distinct vision $(25 \mathrm{cm})$ when the object is $4 \mathrm{cm}$ from the objective. Calculate the focal lengths of the objective and the eyepiece, assuming that the magnifying power of the microscope is $1.$

The ratio of the magnifying power of a convex lens used as a simple microscope when it is used to throw an image at the least distance of distinct vision to the magnifying power when it is used to throw an image at infinity is $6:5$ If the focal length of the lens is $4.8 \mathrm{cm}$, find the least distance of distinct vision.

How can you construct a simple microscope by means of a single convex lens? What is meant by its magnification ?