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

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

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

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

Which of the following statement is true ?

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 ?

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?

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?