Physics - Geometrical Optics Question with Solution | TestHub

In a compound microscope, the objective lens is placed very close to the object.

To achieve high magnification, the focal length of the objective lens must be very small, since the magnification produced by the objective is inversely proportional to its focal length.

The aperture of the objective lens is also kept small to minimize spherical and chromatic aberrations, and because the object is very small and placed close to the lens, a large aperture is not required to gather sufficient light.

Thus, both the focal length and the aperture of the objective lens are small.

Answer: small and small.