Which type of lens is most commonly seen and is used in magnifying glasses?

A convex lens is the type most commonly seen in magnifying glasses. This lens is thicker in the center than at the edges, which allows it to converge light rays that pass through it. When an object is positioned close to a convex lens, the lens causes the light rays to diverge in such a way that they appear to be coming from a larger virtual image of the object. This characteristic of bending light is what enables magnifying glasses to enlarge the appearance of objects.

Convex lenses are widely used in various optical devices, not just magnifying glasses, because they effectively gather and focus light. This property makes them essential in applications ranging from eyeglasses to cameras to telescopes, where the magnification of images is important. The other types of lenses listed serve different purposes and do not provide the same magnifying effect as convex lenses.