Question

Sudha finds out that the sharp image of the widow pane of her science laboratory is formed on a screen kept at a distance of 15 cm from the lens. She now tries to focus the building visible to her outside the window instead of the window pane without disturbing the lens. In which direction will she move the screen to obtain a sharp image of the building?

Answer 1

As the image formed is real, therefore, the lens in use is a convex lens. The distance of the real image formed by a convex lens from the lens decreases as the object distance from the lens increases. As the object distance becomes infinity, the real image is formed on the focus.

Hence, the screen has to be moved towards the lens to obtain the sharp image of the building.