Two concave lenses each of focal length `30 cm` are placed in contact. What is focal of the compound lens ?

Two concave lenses, eacb of focal length 30 cm are placed in contact with each other. Find the power of the combination.

A convex lens of focal length A and a concave lens of focal length B are placed in contact. The focal length of the combination is

A convex lens of focal length x and a concave lens of focal length y are placed in contact. The focal length of the combination is

A convex lens of focal length A and a concave lens of focal length B are placed in contact. The focal length of the combination is

A convex lens of focal lenth 30 cm and a concave lens of focal length 60 cm are placed in contact.Find the power of the combination.

Two convex lenses of focal length 10 cm each are combined. What will be the focal length of the combined lens ?

Find the effective power and focal length of two lenses of focal lengths 50 cm and -200 cm when put in contact. What is the nature of the combined lens?

Two thin concave lenses of focal lengths 10 cm and 30 cm and a thin convex lens of focal length 30 cm are kept in contact. What will be the power of lens combination ?