Question

what do you mean by spherical lens and where it used?

Answer 1

spherical lens are two types lene concave lens or convex lens these are used in hospitals,colleges,schools etc.

Answer 2

If you are a vertebrate with eyes, then you have lenses. The same goes for octopus, squid, and cuttlefish (which are all cephalopods). Common optical devices that use lenses include eyeglasses, contact lenses, magnifying glasses, cameras, projectors, telescopes, binoculars, and microscopes. All sorts of things will act like lenses, even things that aren't normally thought of as lenses. As long as they're transparent and curved, they satisfy the definition and will behave in a manner similar to the devices commonly thought of as lenses. Car headlights and taillights are covered with lenses. (They're even called lenses in auto parts catalogs.) A drop of water is a lens. So are fishbowls, light bulbs, and drinking glasses. In general, a lens is any piece of transparent material with at least one curved surface.

The origins of the word lens can be traced back to the Seventeenth Century. Scientists at the time wanted a word to describe the shape of the glass pieces used in microscopes, telescopes, magnifying glasses, and reading glasses. For some unknown reason they decided against the strictly descriptive term "biconvex" (curved outward on two sides) and instead chose to name them for the small, flat beans they resemble — lentils. Lens lentis is the Latin word for lentil. It's good word for English speakers since few of us associate lenses with lentils and not all lenses are lentil shaped.