Grade 7 | Science | Lens, Light, Olympiad, CBSE, ICSE, SOF, ITO
A lens is a curved piece of glass or plastic designed to refract light in a specific way. Lenses are used in glasses and contacts to help correct vision.
Basic terms related to lens
The focal point of a lens is generally noted by the capital letter "F." This is the point in space where the light rays will converge to after passing through a converging lens. A diverging lens will have a negative focal point where the rays originate from before diverging through the lens.
The focal length is the distance from the center of the lens to the focal point.
The principal axis is a horizontal imaginary line drawn through the center of the lens. In a perfect lens the focal point will reside on the principal axis at a distance of the focal length from the center of the lens.