$A$ microscope has an objective of focal length $1 \ cm$ and an eyepiece of focal length $6 \ cm$. If the tube length is $30 \ cm$ and the image is formed at the least distance of distinct vision,what is the magnification produced by the microscope? Take $D = 25 \ cm$.

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

In a compound microscope,the focal length of the objective lens is $1.2 \, cm$ and the focal length of the eyepiece is $3.0 \, cm$. When the object is kept at $1.25 \, cm$ in front of the objective,the final image is formed at infinity. The magnifying power of the compound microscope is:

$A$ 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 $....$

$A$ wire mesh consisting of very small squares is viewed at a distance of $8 \, cm$ through a magnifying converging lens of focal length $10 \, cm$,kept close to the eye. The magnification produced by the lens is

The angular magnification of a simple microscope can be increased by increasing