Fingerprints are observed by the use of

$A$ compound microscope consists of an objective lens of focal length $1 \, cm$ and an eyepiece of focal length $5 \, cm$ with a separation of $10 \, cm$. The distance between an object and the objective lens,at which the strain on the eye is minimum,is $\frac{n}{40} \, cm$. The value of $n$ is $....$

The focal length of the objective lens of a compound microscope is

The focal lengths of the objective and the eye-piece of a compound microscope are $2.0 \, cm$ and $3.0 \, cm$ respectively. The distance between the objective and the eye-piece is $15.0 \, cm$. The final image formed by the eye-piece is at infinity. The two lenses are thin. The distances in $cm$ of the object and the image produced by the objective measured from the objective lens are respectively:

$A$ microscope has an objective of focal length $2 \ cm$,an eyepiece of focal length $4 \ cm$,and a tube length of $40 \ cm$. If the distance of distinct vision is $25 \ cm$,the magnification of the microscope is:

$A$ compound microscope has a magnifying power of $30$. The focal length of its eyepiece is $5 \ cm$. Assuming the final image is at the least distance of distinct vision $(25 \ cm)$,the magnification produced by the objective is: