$A$ 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

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

An angular magnification (magnifying power) of $30X$ is desired using an objective of focal length $1.25 \, cm$ and an eyepiece of focal length $5 \, cm$. How will you set up the compound microscope?

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:

$A$ student measures the thickness of a human hair by looking at it through a microscope of magnification $100$. He makes $20$ observations and finds that the average width of the hair in the field of view of the microscope is $3.5 \; mm$. What is the estimate on the thickness (in $mm$) of hair?

Obtain the equation of magnification for a compound microscope.