An object is placed 20 cm in front of a plane mirror. The mirror is moved 2 cm towards the object. The distance between the positions of the original and final images seen in the mirror is:

A concave mirror produces a magnification of +4. The object is placed:

A ray of light passes from a medium X to another medium Y. No refraction of light occurs if the ray of light hits the boundary of medium Y at an angle of:

A student does the experiment on tracing the path of a ray of light passing through a rectangular glass slab for different angles of incidence. He can get a correct measure of the angle of incidence and the angle of emergence by following the labelling indicated in figure:

Focal length of plane mirror is

In optics an object which has higher refractive index is called

The number of images observable between two parallel mirrors is :

Total internal reflection of light is possible when light enters from :

A man runs towards the plane mirror at 2 m/s. The relative speed of his image with respect to him will be:

Refractive index: