A ray is incident at an angle of 20^o to a plane mirror as shown in figure. If mirror is rotated by 10^o in ACW direction and incident ray is rotated by 10^o in CW direction then the reflected ray will be rotated by

In the figure shown, a thick plano convex lens is silvered at both the surfaces. A point source of light 'S' is inside the lens. The radius of curvature of the spherical curved surface is (8/3) cm and the distance 'S' from the curved surface is 2 cm. If the images formed due to direct reflections from the plane and curved surface coincide, then find the thickness of the lens in cm.

There is a convex mirror of radius 50 cm. The image of a point at a distance 50 cm from the pole of mirror on its axis will be formed at:

A girl stands at a distance 50 cm from the mirror. She is able to see her erect image but of 1/5 height of actual height. The mirror will be 

Two plane mirrors are inclined to each other ray of light incident on one face at 30^∘ after reflection from the second retraces the path. What is the angle between the mirrors?

A dentist wants a small mirror that when placed 2 cm from a tooth, will produce 3 × upright image. What kind of mirror must be used and what must its focal length be?

The plane of a mirror makes an angle of 30^∘ with horizontal. If a vertical ray is incident on a mirror, then what is the angle between mirror and reflected ray?

The focal length of a concave mirror is 30 cm. Find the position of the object in front of the mirror, so that the image is three times the size of the object.

Two plane mirrors of length L are separated by distance L and a man M₂​ is standing at distance L from the connecting line of mirrors as shown in figure. A man M1​ is walking in a straight line at distance 2L parallel to mirrors at speed u, then man M₂​ at O will be able to see image of M1​ for time :

A mobile phone of width 5 cm and length 10 cm, is placed parallel to its lengths, such that one of its lengths is along the principal axis of a concave mirror of focal length 30 cm. The far point of its length is at the centre of curvature of the mirror. The width of the image will be