Study the diagram below. Complete the diagram to form the image of the object AB.

A diverging lens is a concave lens. The refraction of light rays as they pass through the lens determines how well the lens works. When light rays enter a concave lens, they diverge, causing the lens to behave like a diverging lens. Concave lenses create only virtual images.

Study the diagram given below. State the three characteristics of the image.

The convex lens is comparably thick in the middle and narrow at the bottom and upper borders, and converges light rays that move parallel to its principal axis (i.e. converges incident rays towards the principal axis). The edges curve outward instead of bending within. The image is always virtual. The image is always erect. The image is always diminished in size.

Study the diagram given below. Name a device in which this action of lens is used.

This action of lens is used in a magnifying glass. Convex lenses converge parallel rays going in and, convex lenses diverge rays. A convex lens is useful as a magnifying glass as it will produce a virtual enlarged image if the object is brought within the focal length.

Study the diagram below. Name the lens LL’

LL' is concave lens. Concave lenses always form virtual images, so magnification produced by a concave lens is always positive. A concave lens always forms the image smaller than the object.

LL' is concave lens. what are the points O, O’ called?

The points O and O' are called second and first focal points respectively. The distance between the convex lens or a concave mirror and the focal point of a lens or mirror is called the focal length. It is the point where parallel rays of light meet or converge. The focal length varies with the sign (positive or negative) depending upon the nature of the lens and mirror(concave or convex).