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:

The focal lengths of the objective and the eyepiece of a compound microscope are $2 \,cm$ and $3 \,cm$ respectively, and the distance between them is $15 \,cm$. The final image formed by the eyepiece is at infinity. The distances of the object and the image produced by the objective lens from the objective lens are respectively:

$A$ person using a lens as a simple microscope sees an:

$A$ compound microscope is designed with two symmetric biconvex lenses. The objective lens is cut vertically, creating two identical plano-convex lenses. One of them is used in place of the original objective lens. To retain the same magnification while keeping the object distance unchanged, the tube length has to be

$A$ 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?

What are the objective and the eye-piece in an optical instrument?