From the ray diagram shown in Fig. calculte the focal length of concave lens.
.

From the ray diagram shown below, calculate the focal length of the other convex lens.

Ray coming from an object situated at infinity, fall on a convex lens and an image is formed at a distance of 16 cm from the lens. When a concave lens is kept in contact with the convex lens, the image is formed at a distance of 20 cm from the lens combination. Calculate the focal length of the concave lens.

In the diagram shows below rays are coming from infinity and after passing through both the lenses meet on a screen placed at a distance of 30 cm from the concave lens. Calculate the focal length of the concave lens.

Use the following ray diagram, Fig. to calculate focal length of lens L_2 . .

An arrangement of a concave and a convex lens is shown below. The focal length of the convex lens is 30 cm. Parallel rays coming from a distant source are focused on the screen after passing through the lenses. Calculate the focal length of the concave lens.

Use the following ray diagram, Fig. 6(b).56 to calculate focal length of lens L_(2) .

A concave lens is placed in contact with a convex lens of focal length 25 cm . The combination produces a real image at a distance of 80 cm , when an object is at a distance of 40 cm . What is the focal length of concave lens ?

Find the focal length of the lens shown in Fig.