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

Asked by Topperlearning User | 6th Dec, 2013, 08:52: AM

Expert 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.

This method is not applicable to a concave lens, as image formed by a concave lens is virtual and it cannot be taken on a screen.

Answered by  | 6th Dec, 2013, 10:52: AM