The ability to see is called vision. It is also called eyesight. Sometimes the eye of a person cannot focus the image of an object on the re...

An eye can focus the images of the distant objects as well as the nearby objects on its retina by changing the focal length ( or converging ...

There are similar rules for constructive ray-diagrams for obtaining image with concave lenses. Rule 1. A ray of light which is parallel to t...

The image is formed at that point where at least two refracted light rays meet ( or appear to meet ) . Rules for convex lens :  1. Light ray...

The working of a lens is based on the refraction of light rays when they pass through it . A lens is a piece of transparent glass bound by t...