Show by drawing a ray-diagram that the image of an object formed by a concave lens is virtual, erect and diminished.

Things always look small on viewing through a lens. What is the nature of the lens?

An object lies at a distance of 2f from a concave lens of focal length f. Draw a ray-diagram to illustrate the image formation.

Give the position, size and nature of image formed by a concave lens when the object is placed:

(a) Anywhere between optical center and infinity.

(b) At infinity.

Which type of lens is?

(a) A converging lens, and which is

(b) A diverging lens? Explain your answer with diagrams.