A concave lens is kept in contact with a convex lens of focal length 20 cm. The combination behaves as a convex lens of focal length 50 cm . Find the power of concave lens.

A concave lens is kept in contact with convex lens of focal length 20 cm. The combination works as a convex lens of focal length 50 cm. Find the power of concave lens.

A concave lens is kept in contact with a convex lens of focal length 20 cm.The combbination works as a convex lens of focal length 50 cm.Find the power of the concave lens.

A concave lens is kept in contact with convex lens of focal length 20 cm.The combination works as convex lens of focal length 50 cm. Find the power of concave lens.

A concave lens is kept in contact with a convex lens of focal length 20 cm . The combination works as a converging lens of focal length 100 cm . Calculate power of concave lens.

a concave lens of focal length 20cm is placed in contact with a convex lens of focal length 40cm. Find the power of the combination.

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

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

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 power +2.5 D is in contact with a concave lens of focal length 25 cm. The power of combination is