The power of two convex lenses $A$ and $B$ are $8$ diopters and $4$ diopters respectively. If they are to be used as a simple microscope,the magnification of

The objective and the eyepiece of a microscope have focal lengths of $4 \, mm$ and $25 \, mm$,respectively. The objective produces a real image $30$ times the size of the object. The final image is viewed at infinity. The near point of the microscope user is at $25 \, cm$. The overall magnification of the microscope is

The length of the tube of a microscope is $10 \, cm$. The focal lengths of the objective and eye lenses are $0.5 \, cm$ and $1.0 \, cm$ respectively. The magnifying power of the microscope is about:

$A$ thin convex lens of focal length $5 \, cm$ is used as a simple microscope by a person with a normal near point located $25 \, cm$ away. What is the magnifying power of the microscope?

$(a)$ $A$ card sheet divided into squares each of size $1 \; mm^2$ is being viewed through a magnifying glass (a converging lens of focal length $9 \; cm$) held close to the eye. Where should the lens be held in order to view the squares distinctly with the maximum possible magnifying power?
$(b)$ What is the magnification in this case?
$(c)$ Is the magnification equal to the magnifying power in this case? Explain.

The focal lengths of the objective and the eyepiece of a compound microscope are $1 \, cm$ and $5 \, cm$ respectively. An object is placed at a distance of $1.1 \, cm$ from the objective. If the final image is formed at infinity,the magnifying power of the microscope is: