Question

A compound microscope consists of two converging lenses. One of them, of smaller aperture and smaller focal length, is called objective and the other of slightly larger aperture and slightly larger focal length is called eye-piece. Both lenses are fitted in a tube with an arrangement to vary the distance between them. A tiny object is placed in front of the objective at a distance slightly greater than its focal length. The objective produces the image of the object which acts as an object for the eye-piece. The eye-piece, in turn, produces the final magnified image.

Which of the following is not correct in the context of a compound microscope?

Options

• Both lenses are of short focal lengths.

• The magnifying power increases by decreasing the focal lengths of the two lenses.

• The distance between the two lenses is more than (f_o + f_e)·

• The microscope can be used as a telescope by interchanging the two lenses.

Answer 1

The microscope can be used as a telescope by interchanging the two lenses.

Explanation:

Because both of the microscope's lenses have short focal lengths, the microscope cannot be utilised as a telescope by swapping the two lenses. The telescope's objective has a long focal length.