In the figure shown below, AB is a linear object and A'B' is its image formed by the lens. What type of lens it is?

Which of the following statement is true ?

The image of an object formed by a convex lens of focal length 5 cm is virtual, erect and magnified. What is the range of object distance from the lens?

The focal length of 4 lenses P, Q, R and S are 10 cm, 20 cm, 30 cm and 40 cm. The lens which has maximum power is

Radius of curvature of a concave mirror is 40 cm. Where should an object be placed from the mirror so that its image is formed at infinity ?

Refractive index of glass is maximum for which of the following colors of light?

Radius of curvature of a concave mirror is 40 cm. What is the nature of the image formed if an object is placed at a distance of 19.9 cm from the mirror ?

The image formed by a concave mirror of focal length 24 cm is real and of magnification -1. The distance between the object and its image is

A point object is placed on the principal axis of a concave mirror at a distance of 50 cm from its pole. Its image is formed at the point of the object itself. What is the focal length of the mirror?

The ratio of size of the image to the size of the object is known as