Lenses

A lens is a transparent medium

A lens is a transparent medium bound by two surfaces. A convex lens is thicker at the centre than at the edges and acts as a converging lens. A concav

The optical centre is the point

The optical centre is the point through which light passes without changing direction. The principal axis is the imaginary line passing through both c

A ray parallel to the principal

A ray parallel to the principal axis passes through the principal focus after refraction. A ray passing through the principal focus becomes parallel t

A convex lens can form real

A convex lens can form real or virtual images depending on the object position. If the object is beyond 2F1, the image forms between F2 and 2F2 and is

A concave lens always forms

A concave lens always forms a virtual, erect, and smaller image. For an object at infinity, the image forms at the focus. For an object anywhere betwe