A convergent beam of light converges to a point `20 cm` behind the convex mirrorr on the principal axis.An inverted image of the same size is formed coincident with the virtual object. Then, the focal length of the convex mirrorr is

Two point objects A and B are kept on the principal axis of a convex lens as shown. Image of both the objects is formed at same position. Find the focal length of the lens.

A point object is placed at a distance of 12 cm from a convex lens of focal length 10 cm. On the other side of the lens, a convex mirror is placed at a distance of 10 cm from the lens such that the image formed by the combination coincides with the object itself. The focal length of the convex mirror is

A beam of light converges towards a point O ,behind a convex mirror of focal length 20 cm.Find the nature and position of image if the point O is- (1) 10 cm behind the mirror, (2) 30 cm behind the mirror

A beam of light converges at a point P. Now a convex lens of focal length 30 cm placed in the path of the convergent beam 12 cm from P. The point at which the beam converges now is