A convex lens of focal length 20cm and another plano convex lens of focal length 40cm are placed co-axially . The plano convex lens is silvered on plane surface. What should be the distance (in cm) so that final image of the object 'O' is formed on O itself.

A convex lens of focal length 20 cm and another planocovex lens of foal length 40 cm are placed co-axially. The plane surface of the plano convex lens is silvered. An object O is kept on the principal axis at a distance of 10 cm from the convex lens (see Figure). Find the distance d between the two lenses so that final image is formed on the object itself.

A convex lens of focal length 40cm is in contact with a concave lens of focal length 25cm. The power of the combination is

A convex lens of Focal length of 40cm is in contact with a concave lens of focal length 25cm. The power of the combination is.

A convex lens of focal length 20 cm and a concave lens of focal length 10 cm are placed 20 cm apart. In between them an object placed at distance x from the convex lens. What is the value of x (in cm ) so that images from by both the lenses coincides ?

A convex lens of focal length 20 cm and a convex mirror of focal length 10 cm are placed co-axially 50 cm apart from each other. An incident on the convex lens. Locate the position of final image formed due to the combination. (NCERT Solved Example)

A convex lens of focal length 10.0 cm is placed in contact with a convex lens of 15.0 cm focal length. What is the focal length of the combination ?

A convex lens of focal length 20 cm and a convex mirror of focal length 10 cm are placed co-axially 50 cm apart from each other. An incident beam parallel to its principal axis is incideent on the convex lens. Locate the position of final image formed due to the combination.