Watch repairers use a magnifying glass. Give reason

Explanation

(1) When an object is placed within the focal length of a magnifying glass or simple microscope (convex leps ), its larger and erect image is obtained on the same side of the lens as that of the object.
(2) By adjusting the distance between the object and the lens, the image can be obtained at the minimum distance of distinct vision. Thus, a watch repairer can see the minute parts of a watch more clearly with the aid of a magnifying glass (a simple microscope) than with the naked eye, without any stress on the eye. Hence, watch repairers use a magnifying glass (a simple microscope) while repairing the watches.