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A convex lens is placed in contact with a plane mirror. An axial point object at a distance of 20 cm from this combination, has its image coinciding with itself. What is the focal length of the convex lens ?

A convex lens is placed in contact with a plane mirror. An axial point object at a distance of 20 cm from this combination, has its image coinciding with itself. What is the focal length of the convex lens ?

A convex lens is placed in contact with a plane mirror.A point object at a distance of 20 cm on the axis f this combinatin has its image coinciding with itself.What is the focal length of the lens?

A convex lens is placed in contact with with a plane mirror . A point object at a distance of 20cm on the axis of this combination has its image coinciding with itself. What is the focal length of the lens?

An object at a distance of 30 cm from a concave mirror gets its image at the same point. The focal length of the mirror is

A convex lens and a convex mirror of radius of curvature 20 cm are placed co-axially with the convex mirror placed at a distance of 30 cm from the lens. For a point object at a distance of 25 cm from the lens, the final image due to this combination coincides with the object itself. What is the focal length of convex lens ?