FOCAL POINT AND FOCAL LENGTH OF CONCAVE AND CONVEX LENS

Finding Focal Length Of A Convex Lens

The focal length of a convex lens is

We combined a convex lens of focal length f_(1) and concave lens of focal lengths f_(2) and their combined focal length was F . The combination of these lenses will behave like a concave lens, if

(a) Can you measure rough focal length of a convex lens? If yes, why? (b) Can you measure rough focal length of a concave lens ? If not, why not?

Match the items given in A, B, C and D against. their corresponding description given in 1, 2, 3, 4 and 5. A. Astronomical telescope B. Galilean Telescope C. Simple Microscope D. Compound Microscope 1. contains one convex lens 2. contains one concave lens 3. contains a convex lens of large focal length in the objective and a convex lens of small focal length in the eye-piece 4. contains a convex lens of small focal length in the objective and a convex lens of large focal length in the eye-piece 5. contains a convex lens of large focal length in the objective and a concave lens of small focal length in the eye-piece

A convex lens of focal length 30 cm , a concave lens of focal length 120 cm , and a plane mirror are arranged as shown . For an object kept at a distance of 60 cm from the convex lens, the final image, formed by the combination , is a real image , at a distance of : |"Focal length" | = |"Focal length"| = 30 cm " " =120 cm

A convex lens of focal length f cut into parts first horizontally and then vertically. Find the focal length of part A of the lens, as shown: