Q26 of 38 Page 83

Sudha finds out that the sharp image of the window pane of her science laboratory is formed 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? What is the approximate focal length of this lens?

To get a sharp image of the object, Sudha should move the screen towards the lens and keeping the lens fixed because the object is now placed at beyond 2f and the lens will form the image towards on opposite side between F and 2F.


Since the actual distance between the window pane and the mirror is 15 cm. So, the approximate focal length of the lens will be approximately 15 cm.


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