Question

How do you find the rough focal length of a convex lens? Is the same method applicable to a concave lens? Which factors determine the focal length of a lens?

Answer 1

Answer:

The rough focal length of a convex lens is obtained by forming sharp image of a very distant object on a screen. The distance of the screen from the lens gives us the rough focal length of the lens.

Answer 2

Answer:

The rough focal length of a convex lens is obtained by forming sharp image of a very distant object on a screen. The distance of the screen from the lens gives us the rough focal length of the lens.