A concave lens of focal length 20 cm placed in contact with ah plane mirror acts as a convex mirror of focal length

A concave lens of focal length 20 cm placed in contact with a plane mirror acts as a

A concave lens of focal length 20 cm placed in contact with a plane mirror acts as a

A convex lens of focal length 10 cm is placed in contact with a concave lens of focal length 20 cm. The focal length of this combination of lenses will be:

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 thin convex lens of focal length 10 cm is placed in contact with a concave lens of same material and of same focal length. The focal length of combination will be

A convex lens of focal length 20 cm is placed in contact with a concave lens of focal length 10 cm. What is the focal length and power of the combination ?

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 ?