Question

In an experiment to determine the focal length of a convex lens, a student obtained a sharp inverted image of a distant tree on the screen behind the lens. She then removed the screen and looked through the lens in the direction of the object. What will she observe?

Answer 1

The screen is just a device to observe the real image formed by a convex lens. The image of a distant object continues to get formed at focus of the convex lens even when no screen is being used to show its formation.