Lenses are used in cameras, telescopes, binoculars, microscopes and corrective glasses. A lens can be convex or concave .

Unit 6 Segment L: Spherical Mirrors The properties of spherical mirrors are discussed.

Convex and concave lenses can both be used to correct defects of vision. The most commonly occurring defects of vision are ‘short sightedness’ and ‘long sightedness’. People who are ...

Source: NOVA: "Galileo's Battle for the Heavens" This resource was adapted from NOVA: "Galileo's Battle for the Heavens." The first telescopes, invented in 1608, consisted of two simple concave ...

The properties of concave and convex lenses were first described around the year 1000, although magnifiers in the form of lens-shaped crystals or glass may have been used much earlier.