Question
A student obtained a sharp image of the grills of a window on a screen using a concave mirror. His teacher remarked that for getting better results a well-lit distant object (preferably the sun) should be focused on the screen. What should be done for this purpose?
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Move the screen slightly away from the mirror
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Move the mirror slightly towards the screen
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Move the screen and the mirror away from the object
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Move the screen and the mirror towards the object
Solution
B.
Move the mirror slightly towards the screen
When the image distance increases, object distance decreases. Thus, distance between the mirror and screen will decrease. So, the mirror should be moved towards the screen.
