 # In which of the following, the image of an object placed at infinity will be highly diminished and point sized? (a) Concave mirror only (b) Convex mirror only (c) Convex lens only (d) Concave mirror, convex mirror, concave lens and convex lens

Answer: (d) Concave mirror, convex mirror, concave lens and convex lens

A highly diminished picture is generated at the focus when rays of light from infinity hit a concave mirror, convex mirror, concave lens, or convex lens.

## Convex lens

• A convex lens is a lens with an outward curve.
• The thickness at the centre of a convex lens is more than the thickness at the edges of the lens.
• Convex lenses are converging lenses. They have the ability to converge a parallel beam of light into a point.
• The lens found in the human eye is a prime example of a convex lens.
• Another common example of a convex lens is the magnifying glass that is used to correct Hypermetropia or long-sightedness.

## Concave lens

• A concave lens is a type of lens with at least one side curved inwards.
• A concave lens with both sides curved inward is known as a biconcave lens.
• Concave lenses are diverging lenses, that is, they spread out light rays that have been refracted through them.
• They have the ability to diverge a parallel beam of light.
• For a concave lens, the edges are wider than the centre or the centre is thinner than the edges.
• Concave lenses are used in spectacles in order to overcome myopia or short-sightedness.

### Concave mirror

In the case of a concave mirror, an image may be real or virtual, inverted or erect and magnified or diminished depending upon the position of the object.

### Convex mirror

In the case of a convex mirror, an image formed will always be virtual, erect and diminished in spite of the position of the object. (1) (0)