In a compound microscope,the focal length of the objective and eyepiece lens is $4\,cm$ and $8\,cm$ respectively. If the length of the tube is $30\,cm$,then the magnifying power for normal adjustment is:

If in a compound microscope, the objective has a focal length of $1.0 \text{ cm}$, the eyepiece has a focal length of $2.0 \text{ cm}$, the tube length is $20 \text{ cm}$, and the near point for an observer is $25 \text{ cm}$, then the value of the magnification of the compound microscope will be . . . . . . .

What is the magnifying power of a simple microscope of focal length $5 \ cm$,if the image is formed at the distance of distinct vision?

$A$ simple microscope is used to see an object first in blue light and then in red light. Due to the change from blue to red light, its magnifying power

Magnification of a compound microscope is $30$. The focal length of the eyepiece is $5 \, cm$ and the image is formed at the near point (distance of distinct vision) of $25 \, cm$. The magnification of the objective lens is:

Obtain the magnification for the image formed at infinity for a simple microscope.