A converging lens of focal length `5.0cm` is placed in contact
with a diverging lens of focal length `10.0cm.` Find the combined focal length of
the system.

A converging lens of focal length 40 cm is kept in contact with a diverging lens of focal length 30 cm. Find the focal length of the combination.

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

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 ?

A converging lens of focal length 30 cm is placed in contact with another converging lens of unknown focal length, then possible value for focal length of combination is

A converging lens of focal length 30 cm is placed in contact with another converging lens of unknown focal length, then possible value for focal length of combination is

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

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: